PDA

View Full Version : Film speed testing



macandal
19-Nov-2012, 12:26
Okay, I'm trying to do a film speed testing, but the two sources I have, do it in increments/decreases of 1/2 or 1/3 stops. Now, I'm a newbie. 1/2 and 1/3 stops may not be complicated to you more experienced fellows, but they are to me, a beginner soul. Can someone please give me the easy version of the film speed test? In whole stops? None of this half or third business? These are my requirements:

I'm testing my large format Sinar F2 (obviously sheet film)
I have access to a densitometer
I have a gray card (I know there are ways of doing this test without one, but I want to do it with a card)

I think that's it. I can't think of anything else. Can someone give me the easy version of the film speed test? Thanks.

SpeedGraphicMan
19-Nov-2012, 12:28
Give this a read through...

http://www.earthscenics.com/manuals/zoneman_8_11_05.pdf

ic-racer
19-Nov-2012, 13:08
Guess at an exposure index, set that on the meter, expose the card putting it at zone 1, process the film and check that it is 0.1 log d. Repeat as needed to find the proper exposure index.

polyglot
19-Nov-2012, 21:08
I would recommend acquiring a copy of Beyond The Zone System by Davis. It lays it all out fairly neatly, though you will need to buy a (not very expensive) step wedge.

Bill Burk
19-Nov-2012, 22:53
Get a ride to Pacifica and bring about 10 sheets of film...

I need a guinea pig to practice the material for my class... "Calling your shots, the timeless appeal of popular sensitometry". So you'll be helping me and in the end you'll either be totally confused, or you'll know every way to test film...

Bill, 70's military B&W
20-Nov-2012, 18:50
Re: Film speed testing
Give this a read through...

http://www.earthscenics.com/manuals/zoneman_8_11_05.pdf

I'm just getting started in LF myself, and am about ready to start doing some testing on my own, hopefully this weekend. I have several lenses and cameras.

I read the above and I wonder if it means that you would have to do the calibration for each camera/lens combination you have??? A different ISO for this camera with that lens...etc?
Or does the camera have very much to do with it? All my lenses are attached to shutters, so would I have to do this test for ISO determination just for each lens?

That is very complicated, how does everyone else handle having more than 1 lens and used on more than 1 camera? I have a speed chart for each lens I have and I keep it with me, I trust the aperture settings.

Thanks, Bill

macandal
20-Nov-2012, 22:25
Re: Film speed testing
Give this a read through...

http://www.earthscenics.com/manuals/zoneman_8_11_05.pdf

I'm just getting started in LF myself, and am about ready to start doing some testing on my own, hopefully this weekend. I have several lenses and cameras.

I read the above and I wonder if it means that you would have to do the calibration for each camera/lens combination you have??? A different ISO for this camera with that lens...etc?
Or does the camera have very much to do with it? All my lenses are attached to shutters, so would I have to do this test for ISO determination just for each lens?

That is very complicated, how does everyone else handle having more than 1 lens and used on more than 1 camera? I have a speed chart for each lens I have and I keep it with me, I trust the aperture settings.

Thanks, BillI'm afraid your worst fears are about to materialize. My understanding is that the combination camera, lens, film is what determines the appropriate film speed. So, depending on how many lenses you use on a given camera, and hoping--for your sake--that you only use one kind of film, that's how many combinations you have of film speed. So, one camera, three lenses, and assuming just one kind of film, will have up to three different results.

Luckily for me, for my 4x5, I only have one lens and one kind of film I use. So my testing becomes very easy.

Bill Burk
20-Nov-2012, 22:46
No it's really not all that bad!

I recommend undertaking this as a journey to understand film exposure and processing - rather than a precision endeavor.

So pick your "normal" setup and follow the Zone System tests that make the most sense to you. It's learning to give enough exposure and developing to suit your needs that's important.

Time and temperature and the massive dev chart and everyone's advice work too because you really have a lot of leeway.

But you get a lot of satisfaction knowing you picked the Exposure Index and development time because they are right for you. You will feel proud of yourself that for once you didn't just follow somebody else's charts without understanding how the charts were created.

Bill, 70's military B&W
21-Nov-2012, 06:01
I appreciate everyones input, and I WILL take the advice.

But thinking of it logically...
The way I see it, the film is a constant, regardless of what camera or lens...
Shutter speed is something that you can test to see what you are actually getting...so that becomes a pretty reliable factor.

The unknown, untested, take on faith factor is the aperture.

Logic would dictate that it is the aperture that has variables in it. f/8 on this lens lets in more light than f/8 on that lens, therefore I have to change the ISO to compensate.
I do not see any other way to compensate except by varying the ISO, but aperture is where I see the problem originating.

I'm a newbie just looking at this and trying to understand it. I'm sure it's been studied/tested, is there any other explanation?

Brian Ellis
21-Nov-2012, 07:03
Re: Film speed testing
Give this a read through...

http://www.earthscenics.com/manuals/zoneman_8_11_05.pdf

I'm just getting started in LF myself, and am about ready to start doing some testing on my own, hopefully this weekend. I have several lenses and cameras.

I read the above and I wonder if it means that you would have to do the calibration for each camera/lens combination you have??? A different ISO for this camera with that lens...etc?
Or does the camera have very much to do with it? All my lenses are attached to shutters, so would I have to do this test for ISO determination just for each lens?

That is very complicated, how does everyone else handle having more than 1 lens and used on more than 1 camera? I have a speed chart for each lens I have and I keep it with me, I trust the aperture settings.

Thanks, Bill

With a shutter that's in the lens (as opposed to being in the camera) as is the case with most lenses used for LF photography the camera has nothing to do with it, only the apertures and shutter speeds of your lenses are relevant in testing to determine your film speed.

You wouldn't normally use different film speeds with different lenses. Many people do test the shutter speeds of all their lenses whether they've made made film speed tests or not just because it's a good idea to know whether there's a significant difference between one or more speeds marked on the shutter and the actual speeds. And if that's done and differences are found they'd adjust the exposures to take that difference into account when they used that shutter speed to make a photograph. While the exposure change could be made by adjusting the film speed it's much simpler to do so by adjusting the shutter speed or aperture rather than trying to figure out what new film speed would give you the desired change in exposure.

But again, testing shutter speeds is something that's often done completely apart from any film speed testing you've done. The film speed you determine after testing for film speed normally remains constant.

Mark MacKenzie
21-Nov-2012, 07:25
No, aperture is a mathematical constant. It is the ratio between the focal length and the diameter of the lens or opening. It is as reliable as any other variable. That said, sure some manufacturers may mis-mark the aperture but I would think its very rare. The film testing is to match your darkroom variables to whatever paper you use to whatever enlarger you use to whatever timer you use, ph of water and so on, etc.

f/8 on a 48" telescope mirror is the same as f/8 on a 50mm Minolta lens. It is a mathematical certainty. You can argue transmission factors but they are miniscule.

For me the beauty of film testing is the expansion or contraction of contrast. This is of paramount importance in the darkroom, perhaps not in Photoshop.


Reading above... I think the danger in anything is not keeping proper prospective as far as to what extent do you need to exert yourself. Sure, you may have a lens that shoots 1/25 and the other shoots 1/27th of a second, but we are just getting into the ballpark, we don't need to know the speed of the fastball unless we are gluttons for punishment.

Seriously, if you are doing scientific studies of light output of the star Sirius, then you should be concerned with fractions of degrees on your thermometer or millisecond differences or how accurate the aperture markings are. For me, I am just wanting to get a good range of light on a piece of paper, sometimes more, sometimes less, but always in my control. I don't want accidental success. I don't mind it, but I don't rely on it.

Read those Ansel books. Honestly, they will tell you all you could ever want to know to make fine photos.

Sorry, one more point. You have to standardize before you can ever know what you are doing. One film, one paper, one developer, etc. Once you know how, say, HC-110 works, then you can play with D-23 or Pyro. It gets easier that way. Its a far shorter path then trying this then that then this then that and wondering why your prints always look like grey fog.

Maybe I've opened my mouth. They say its better to be thought a fool than to open your mouth and remove all doubt...

AJ Edmondson
21-Nov-2012, 08:04
Bill Burk's advice is pretty sound and is worth executing because it is a good learning experience. I realize that we are all different and have different approaches/goals but, having been down about every path proposed over the last 50+ years using field and view cameras I can vouch for the frustration which comes from trying to control - to the nth degree - all of the variables of the photographic process! If you consider, beginning with the light meter, the method of metering, the shutter and diaphragm, the lens transmission factor, the film speed, the amount of lens flare/internal flare, thermometer, agitation.... you get the picture (no pun intended). The list of variables is phenomenal and it is easy to become so enamored of "the perfect negative" that the pure joy of photography is lost amidst the noise. I recall being at some seminar back when Phil Davis first produced the "Beyond the Zone System" series that a fairly well-respected photographer was queried (with regard to the methodology) and his reply was pretty astounding... "get the book, work with it until you understand the approach, and then forget about it" ... (shock).
The truth is - again, my opinion only, the photographic process is pretty tolerant of errors. I also recall being at a seminar with John Sexton and seeing "straight prints" from Ansel Adams "Clearing Winter Storm" (the negative appeared almost bulletproof) and realizing that the art of printing, which is far more controllable, was the better approach for me. At that point I decided to test my equipment only to the extent necessary to prevent gross errors... an annual check of shutter speeds, light meter validation, thermometers. I suppose the approach should be governed by the objective - sensitometry or photography. This is not meant to be derisive of those who choose to pursue the alternatives. (I had to really fight the "test-it-to-death" approach because my profession was metrology conducted under what was then the National Bureau of Standards - now the National Institute of Standards and Technology.)

Bill Burk
21-Nov-2012, 08:12
But thinking of it logically...
The way I see it, the film is a constant, regardless of what camera or lens...
Shutter speed is something that you can test to see what you are actually getting...so that becomes a pretty reliable factor.

The unknown, untested, take on faith factor is the aperture.

Logic would dictate that it is the aperture that has variables in it. f/8 on this lens lets in more light than f/8 on that lens, therefore I have to change the ISO to compensate.
I do not see any other way to compensate except by varying the ISO, but aperture is where I see the problem originating.

People like Stephen Benskin say it's always best to break down to individual variables.

If you were striving for a complete device-independent system, you would separate everything:

-Film speed: test with sensitometer and note the effective film speed for your development technique and quality demands
-Shutter speed: test with shutter tester and mark the shutter with a cheat sheet with the real times
-Aperture: test on optical bench and mark T-Stops (transmission stops) on your lenses like they do for movie cameras.
-Light meter: I've heard of all our devices, the light meter is the most accurate (there is a K factor, which has its own urban legend qualities, the proof is ugly but seems correct to me).
-Flare: Beyond the Zone System describes a test for flare, I like to lay down a costume "top hat" in the picture.

Classic Zone System testing includes all these variables and bunches them together so the test is only valid for your setup at the shutter speed you picked...

I don't say I know how bad each of these variables is, but I can start to name them.

For discussion purposes, I don't think f/stops are that bad. Here's my logic:

Motion picture camera operators need to have very accurate lens markings. They get their lenses bench tested and rated for transmission... T-stops. Still Film Photographers have de-facto accepted f/stops as "good enough". I believe the reason is purely cost - but I wouldn't rule out brainwashing.

So I don't think aperture is that big of a variable. You can send your lenses off to S.K. Grimes and they can engrave an accurate scale for you. Never mind, you say? That's OK.

I hate to read forum posts when people say "don't worry about it, it doesn't matter". So I hope that's not how I'm coming across. I mean... of course it matters and it is important to get your head around it. I am happiest when I use my understanding of a concept to solve a problem. But I also am happy to put my long discussions to rest when I am out taking pictures and shoot at f/4.7 even though if the meter and my calculations indicate f/4.

I think you could test aperture by shooting a test series with Flash! Setup a gray card, terrycloth towel, etc. Then with flash on Manual, shoot at all the different apertures. Measure the result with a densitometer and graph next to a sensitometry test. The difference on the Log-E axis will tell you the real T-stop!

Bill Burk
21-Nov-2012, 08:28
I recall being at some seminar back when Phil Davis first produced the "Beyond the Zone System" series that a fairly well-respected photographer was queried (with regard to the methodology) and his reply was pretty astounding... "get the book, work with it until you understand the approach, and then forget about it" ... (shock)

Thanks AJ Edmondson,

Exactly what I was trying to say... The understanding you gain is what makes the Zone System seminars and books and threads so valuable. Once you internalize it, you are free. And freedom is precious.

Lenny Eiger
21-Nov-2012, 10:44
I think this is very simple. Sure there are a lot of variables, but the differences between lenses isn't going to make that much of an effect - not a whole stop for instance. In addition, this would only affect the shadows. The first thing you would want to do is look at a negative that was perfect.... the one that printed itself. You had to do no burning and dodging and the print came out exactly the way you want it. The very black part of the shadows should be almost clear and the highlights shouldn't blow out. If you don't have an example of this, find someone who does and look hard at their negative. I used to do all the densitometry, taught classes in it at colleges, and now I just look and see if I like what's on the light table. Then I see if it prints... It's only rocket science if you are doing science, comparing two films equally for a review, etc. Making a great negative is about getting the print you want, not necessarily what anyone else wants.

I think Bill Burk's offer is quite generous, he can obviously help, and you should call him on the phone and arrange it. There is nothing like being shown "the ropes" even if you ultimately decide to "improve" on the process for your own purposes.


Lenny

Chuck P.
22-Nov-2012, 10:10
I'm afraid your worst fears are about to materialize. My understanding is that the combination camera, lens, film is what determines the appropriate film speed. So, depending on how many lenses you use on a given camera, and hoping--for your sake--that you only use one kind of film, that's how many combinations you have of film speed. So, one camera, three lenses, and assuming just one kind of film, will have up to three different results.

Luckily for me, for my 4x5, I only have one lens and one kind of film I use. So my testing becomes very easy.

If one believes that this guy (http://www.google.com/search?hl=en&sugexp=les%3B&cp=5&gs_id=i&xhr=t&q=ansel+adams&bpcl=38897761&biw=1440&bih=792&bav=on.2,or.r_gc.r_pw.r_qf.&wrapid=tlif135360395491410&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=mFuuUL-5Mef5ygHk_4GgCA) knew what he was talking about, one would know that he abslolutley did not recommend what you are suggesting here to the OP.

Doremus Scudder
22-Nov-2012, 12:09
Okay, I'm trying to do a film speed testing, ... Can someone give me the easy version of the film speed test? Thanks.

I think we are making things a bit too difficult here. The OP is a beginner and wanted to find a personal film speed. He is daunted by working in fractions of a stop.

Plus, finding a personal E.I. that you can use and get good results from is not all that difficult. Sure, there is a whole lot of science and lots of variables in lenses, cameras, flare, etc. that we can figure in, but I never worried about that when I was starting out.

I recommend to the OP to do a simple test with his grey card, the camera and lens he uses most often and the film he wants to test. This assumes a fairly modern, correctly working shutter. Testing it would be nice, but if 1 second and 1/2 second sound good, that should be fine.

Set the film speed on the meter to half of the box speed of the film (one stop overexposure; e.g., if you are testing 400 speed film, set the meter to 200). Meter the card and place it in Zone 1. Pull the darkslide halfway and shoot (use a slow shutter speed, they are more accurate). Do the same a 1/3 stop slower than box speed (i.e., the next film speed slower than box speed, for 400 speed film that would be 320).

Develop these negatives and read them with the densitometer. Find the Zone I density that is the closest to 0.01 above FB+F without being under that value. Use that for starters. If it looks like the intermediate speed (the one that wasn't tested) is better, e.g., if the 1/3-stop under was just a bit under 0.01 above FB+F, and the one-stop over neg is way over, then use that instead.

Or, you can ditch the densitometer completely and make proper proofs. Find minimum time for maximum black on your printing paper for the clear area of the neg. Print your negs at that time and lighting. Find the strip that just starts to show grey. That's your Zone I and your film speed.

Then do a test for N development and expansions and contractions if you like and go out and shoot. Make adjustments to your system based on your shooting in the field.

That's more than enough to get started and get good results.

Best,

Doremus

Bill Burk
22-Nov-2012, 12:56
I think we are making things a bit too difficult here. The OP is a beginner and wanted to find a personal film speed.

Doremus,

You gave the simplest film test idea, and I endorse it.

As to the other answers being too difficult, sure I went off the deep end. But I believe OP is about to embark on a journey searching for a deeper understanding (so he can soak in the gritty details)... He's asked for books... This is the kind of hunger for knowledge that gets accelerated faster than any learning in schools can deliver (I think I just read an Edward Abbey passage to that effect).

I would say the high level view is... For black and white it's all about "expose for the shadows, develop for the highlights". For color (OP has indicated interest in color), since there are three layers of carefully balanced film, you cannot control contrast by development because it will throw off the balance, so the film gets developed "a standard amount."

I don't know color that well so correct me if I'm wrong: Color balance can be compensated easily with filters. Contrast control is done with masking if necessary. If possible... deal with contrast in advance by altering the light ratio when shooting.

macandal
22-Nov-2012, 14:31
Thanks for all the suggestions folks. I have a question. This may be totally irrelevant, but here goes, why when doing the film speed test, you are asked to go up/down a half stop or a third stop? Why not a full stop? Is there something about half and third stops that I'm not seeing? Thanks.

DennisD
22-Nov-2012, 16:43
Mario,
1/2 or 1/3 stop increments should allow you to hone in on (or come very close to) a densitometer reading of 0.1 above FB + F as described by Doremus. This is better than trying to interpolate. Going in one stop increments might be ok if you're lucky but could easily result in your making an estimate that will lead to determination of a film speed that's not as accurate as you might otherwise achieve.

You really want to the correlate the 0.1 above FB + F densitometer reading as closely as possible with as possible with specific readings - not estimates.

macandal
22-Nov-2012, 16:48
Mario,
1/2 or 1/3 stop increments should allow you to hone in on (or come very close to) a densitometer reading of .01 above FB + F as described by Doremus. This is better than trying to interpolate. Going in one stop increments might be ok but could result in your making an estimate that will lead to your determination of a film speed that's not as accurate as you might otherwise achieve.Ok. I understand that. Half, third, fractions of a stop are more accurate than a full stop.

So, how do I set a half or third stop on my lens? My lens only moves in full stops.

Thank you.

Chuck P.
22-Nov-2012, 16:55
It's actually 0.1 above fb+f..........

DennisD
22-Nov-2012, 17:02
Does your lens have a linear scale, I.e. equal distance between f stop markings ?

If so, you can carefully position the f stop in between f11 & f16, for example, to get a half stop difference. Some lenses actually have click stops at f stops and at intervals in-between f stops.

If the f stop scale is non linear, it's a bit of guesswork to find the proper mid point.

DennisD
22-Nov-2012, 17:07
It's actually 0.1 above fb+f..........

Thanks Chuck. You are very correct. I copied and pasted blindly and should have caught that.

macandal, please take note !

Correction made to original post which was still editable

Brian Ellis
22-Nov-2012, 17:32
I think we are making things a bit too difficult here. The OP is a beginner and wanted to find a personal film speed. He is daunted by working in fractions of a stop. . . .

I agree that some of the answers here go way beyond anything he's likely to understand. But while he asked about ways to find a personal film speed, he also asked some specific questions that indicated some confusion on his part, to wit:

"I read the above and I wonder if it means that you would have to do the calibration for each camera/lens combination you have??? A different ISO for this camera with that lens...etc?
Or does the camera have very much to do with it? All my lenses are attached to shutters, so would I have to do this test for ISO determination just for each lens?"

macandal
22-Nov-2012, 17:41
I agree that some of the answers here go way beyond anything he's likely to understand. But while he asked about ways to find a personal film speed, he also asked some specific questions that indicated some confusion on his part, to wit:

"I read the above and I wonder if it means that you would have to do the calibration for each camera/lens combination you have??? A different ISO for this camera with that lens...etc?
Or does the camera have very much to do with it? All my lenses are attached to shutters, so would I have to do this test for ISO determination just for each lens?"Brian, that wasn't me. I, macandal or Mario, am the OP. That question was asked by someone else reading this thread.

Brian Ellis
22-Nov-2012, 17:47
Brian, that wasn't me. I, macandal or Mario, am the OP. That question was asked by someone else reading this thread.

Oh, O.K., thanks. I didn't notice that. Hopefully I helped him if not you.

Pawlowski6132
22-Nov-2012, 18:41
Why do you want to do film testing???????

Chuck P.
22-Nov-2012, 19:24
Why do you want to do film testing???????

We should take that to be facetious, I suppose.............

Pawlowski6132
22-Nov-2012, 19:56
We should take that to be facetious, I suppose.............

Nope, that's a legit question.

Are you implying that it's so necessary that the answer is obvious?

Bill Burk
22-Nov-2012, 20:42
By the way, half stop and third stop are common increments on the step wedges that are used for contact testing.

Cameras and light meters typically have marks or steps at 1/3 stop increments. My old Pentax lenses had detents at 1/2 stop increments.

In Minor White's 1963 Zone System manual he recommends a test using four sheets... Rated speed, +1/3 stop, -1/3 stop and + 1 stop. It's as if he just wants to make sure you hit one that works.

Doremus Scudder
23-Nov-2012, 02:54
Correction first: 0.1 above film-base+fog is the accepted value in the Zone System for Zone I and film speed. Sorry for any confusion, I simply mistyped (or had the number in my head wrong). Thanks to Chuck for pointing out my error.

About third-stop increments: ISO numbers are in one-third stop increments. A doubling of the ISO number gets you one stop difference. Examples: 200 to 400 ISO is a one-stop difference in film speed; 200 to 250 ISO is a one-third stop difference. Also, many densitometers and step wedges are also in one-third stop increments.

Commonly, shutter speeds are only in one-stop intervals (except for some fancy electronic shutters). Many lenses have aperture scales that are marked in one-third stop increments (most of mine are). If yours are not, estimating the distance between printed f-stops is almost always close enough.

A one-third stop exposure error is really small, although it does make some difference in color transparency work. For black-and-white, it's practically negligible. That is the reason I advocated doing just two film-speed tests; one at one stop slower than box speed and one at 1/3 stop slower than box speed. After reading with the densitometer, you can just pick the best one of those two, or extrapolate to the ones you didn't take (i.e., 2/3 stop slower than box speed and box speed itself). Rarely will a personal E.I. be outside this range. I also advocate erring on the side of overexposure with black-and-white, especially if you shoot large-format, since the shadow detail is much more important than the extra third-stop of shutter speed or any miniscule increase in grain you might get by overexposing 1/3 stop.

Speaking of Minor White: I learned Zone System calibration from his and Richard Zakia's "The New Zone System Manual." It demonstrates a way to do all the tests without a densitometer. I made Zone Rulers (strips with actual prints of all the different Zones) for all my films and development schemes. These really helped with visualization, which I believe is the major advantage of using the Zone System in the first place.

I still think that testing to take lens flare, differences in aperture calibration, etc. into account is meaningless. If your shutters are not accurate, get them cleaned and adjusted and make a note of the actual shutter speeds at each setting. The other errors are too small to worry about when just setting out to establish a personal E.I. If you are really worried about that stuff, expose an extra third of a stop.

Flare is actually more of an issue with contrast in the lower values than a film-speed issue anyway. One can always print through a bit denser negative. What overall flare does, however, is give a general exposure to the entire film, much like a pre-flash. This can raise the lowest values while at the same time reducing separation in the shadow values, thus changing the curve shape. Older, uncoated lenses will exhibit this characteristic quite a bit; more modern single and multi-coated lenses very little. At any rate, we shouldn't be worrying about that in film speed testing unless we shoot lots of uncoated lenses. I don't, and I'll bet the OP doesn't either.

One wants to do film-speed testing to be sure one is not underexposing and losing shadow detail. Errors in overexposure with B&W film are not so serious, but we don't want to be grossly overexposing either. We need to hit the exposure somewhere between the goalposts of lost shadow detail and blocked highlights. For smaller film formats, issues of grain make us want to be close to the minimum exposure necessary to get adequate shadow detail. Keeping the shutter speed as fast as possible for whatever reason (action photography, etc.) makes us want to do the same. For those of us who shoot large film and are not trying so hard to optimize shutter speeds, there is more wiggle room between the goalposts, and overexposing a bit as a safety factor is an acceptable method.

This means that, yes, test for a personal film speed, but don't get bogged down in unnecessary accuracy; there are a lot a variables in equipment and processing that introduce a lot more error than one-third of a stop. I know I'm not going to get all the apertures on my lenses calibrated, nor am I going to control my processing temperatures to a fraction of a degree Celsius. I'm going to find a personal E.I. that gives enough of a cushion for the variables in my system.

Much more important than film-speed testing are the development tests for different contrasts. The OP should find a usable film speed, erring on the side of overexposure since he is shooting LF and move on to those. I'm sure he'll find lots of advice for doing those here as well :-)

Best,

Doremus

Bill, 70's military B&W
23-Nov-2012, 09:35
Doremus, you have helped me in the past and I appreciate it, I'm trying to understand what you recom here. I think I'm missing something very basis and fundamental, you said to pull the dark slide out half way and make the exposure. Why half way? What happens to the rest of the negative? I'll bet I am missing some very important part of the logic, obviously I am, there has to be a good reason to only pull it out half way.

Also, I have a MacBeth densitometer that was essentially given to me, but I do not know anything about it. Again I know I am missing the fundamentals. Everyone who gives me advice an the densitometer assumes I know more than I do. They always tell me that with a densitometer I can do this and it will show me that, except I can not figure out how to use it. I can not see the forest because of the trees, and I know it. I've read some about it but even there I am quickly left in the dust. I need Basic Densitometry for Dummies. Never have seen a densitometer in use, do I have to calibrate it? It has a zero function, is that enough?

I have a densitometer, I have calibrated 21 step strips both transmission and reflected. How do I use them? I know I do not understand the language of FB+F, it means film base plus fog. Somehow the clear part of the negative around the edges is important, could that be the film base? What is fog?

I still can not go with my densitometer into my DR, with a negative and use it to help me make a better print. I still run a test strip, print a working print, change the contrast, rerun a test strip, then another working print, then work on burning/dodging, possibly selenium toning. This gives me a final print. The densitometer was unused, so was the calibrated test strips.

I'm just beginning and I'm trying to understand the process. I definitely want to try and produce negatives that print themselves. What would help would be a demonstration, actually see one in use. I live 2 hours SW of Atlanta, are there any talks/lectures/classes that address it?

Bill, 70's military B&W
23-Nov-2012, 09:43
Mario, I hope you don't mind me jumping in and asking questions on your thread. It's just that I am having a lot of questions that run parallel to your original questions.
I thought it was easier to ask them here rather than starting another thread on exactly the same topic.
Bill

Bill Burk
23-Nov-2012, 10:05
Doremus, Your post is brilliant. Worth re-reading.

I often say film testing's greatest value is the understanding. Same when it comes to flare. Shoot a top-hat and imagine that the negative image of the hat should be absolutely clear. Then find out (by densitometer or just looking) there is density in the hat. That's how much flare you have. It's meaningless in the sense it only pertains to a picture like that. But you get an understanding.


I have a densitometer, I have calibrated 21 step strips both transmission and reflected. How do I use them? I know I do not understand the language of FB+F, it means film base plus fog. Somehow the clear part of the negative around the edges is important, could that be the film base? What is fog?

Base+Fog is general grayness on the negative that you measure after you develop film that has not been exposed at all. Base is the film plastic material alone. You get Base by fixing film without developing it. Fog is the difference. Base (should) has no grain. Doesn't matter if it is 0.04 or 0.35, it is only clear. Fog will have grain so it is nice to minimize it or wish for less of it. The longer you develop the more you will have.

If you "read" the calibrated step wedges and get the same numbers as written on the calibration sheet (or within 0.02) then you are getting good readings from your densitometer.

Stephen Benskin
23-Nov-2012, 13:19
I basically agree with Doremus that it's more important to understand your processing. Once that is done, pick an EI that works with your approach. Unless you're interested in theory, I wouldn't bother with film speed.

I do disagree with Doremus concerning flare and film speed. Without average flare, film speeds would be one stop slower, but flare is built into the ISO film speed so this is something you usually don't have to worry about. The flare that causes the contrast reduction Doremus describes is also responsible for the effective speed increase. Veiling flare adds proportionally more exposure to the shadows.

Also, Flare doesn't technically change the shape of the film curve. What it does change is the relationship of the subject tones in the optical image, and consequently where the individual subject exposures will fall on the film curve.

Bill, 70's military B&W
23-Nov-2012, 19:18
Bill, thanks, I understand what you wrote about base and fog. I can go and "read" my calibrated wedge test strips to see if my densitometer is in adjustment. Then I can develop unexposed film, and fix undeveloped film. That will give me base and base+fog. I will have a number.

Doremus says to meter a gray card for 1 stop overexposure, another for 1/3 stop overexposure, place both of them on Zone #1, develop normally, and use the densitometer to determine which is closest to 0.01 above base+ fog without being under it. This will be my personal ISO for that film.

Is that right, did I finally get it?
Thanks everyone,
Bill

Chuck P.
23-Nov-2012, 19:21
Nope, that's a legit question.

Are you implying that it's so necessary that the answer is obvious?

I'm implying that the answer is obvious, but not really necessary.......just kidding.

Bill Burk
23-Nov-2012, 20:22
Bill, thanks, I understand what you wrote about base and fog. I can go and "read" my calibrated wedge test strips to see if my densitometer is in adjustment. Then I can develop unexposed film, and fix undeveloped film. That will give me base and base+fog. I will have a number.

Doremus says to meter a gray card for 1 stop overexposure, another for 1/3 stop overexposure, place both of them on Zone #1, develop normally, and use the densitometer to determine which is closest to 0.01 above base+ fog without being under it. This will be my personal ISO for that film.

Is that right, did I finally get it?
Thanks everyone,
Bill

Yes. That's it. You'll have a personal EI compatible with the "Zone System".

Chuck P.
23-Nov-2012, 20:34
I do disagree with Doremus concerning flare and film speed. Without average flare, film speeds would be one stop slower, but flare is built into the ISO film speed so this is something you usually don't have to worry about. The flare that causes the contrast reduction Doremus describes is also responsible for the effective speed increase. Veiling flare adds proportionally more exposure to the shadows.

Stephen, you've said many times that average flare reduces the log H range by 1 to 1 1/3 stops, but I'm curious what that average is in terms of average flare density on top of fb+f, would that be .02, .03, .04?

When you say that flare is built into the ISO film speed, does that mean that a no flare film test (as in what I do when contacting the tablet to the sheet in the holder) could easily render an effective film speed that equals the ISO rating? In no instance have I had the effective film speed for "N" dev differ than the box speed, of course with "plus" and "minus" times increasing and decreasing fog do change the effective speed. You've also said that flare should be factored in post film testing, if flare is already factored into the ISO speed, then how do you mean by that, adding to the effective speed?

Bill Burk
23-Nov-2012, 20:48
p.s. Unless the densitometer is grossly out of calibration, I'd recommend not attempting to calibrate the densitometer.

Bill, 70's military B&W
23-Nov-2012, 21:07
YEAH!!!!!!!! finally, a light comes on, it's a weak candle flame, but I'll do my best to keep it burning,
Thanks to everyone, and I'll be working on it this weekend.
Bill

Stephen Benskin
23-Nov-2012, 23:17
Chuck, lot's of good questions. The answers will require getting into theory which is more advanced than the OP is looking for. So, I'll keep it brief. For more thorough explanations, you can check out a number of other threads. The "What is the relationship between film speed and camera exposure" thread on Apug explains most of your questions and "Is K factor relevant to me or should I factor it out" thread covers a complete explanation of exposure for average illuminance to log-H. The "Hiding in plain sight" thread has a bit of everything.

The value of flare is calculated using the minimum exposure. One stop of flare is simply a doubling of the minimum exposure. To determine what density the addition of flare will produce, just check the density 0.30 log-H units to the right of where the minimum exposure falls. What that density is depends on a number of factors including the shape of the toe. Under average conditions and if you use the ISO film speed, the exposure will fall around 0.10 over Fb+f. Most likely it will generally fall slightly over it.

84163

The non-flare curve shows where the exposure will fall if no flare exists. Flare shifts the shadow exposure in the camera image which places it further up the film curve.

And shown in a slightly different way.

84164

These examples should also explain how a non-flare test can factor in flare (basically without most people noticing). The relationship between the metered camera exposure and the shadow exposure is 4 1/3 stops. The relationship between the metered camera exposure and the speed point is 3 1/3 stops. The difference is one stop which is attributable to flare. The ISO standard basically measures the curve at the point where the shadow exposure plus flare will fall and not where the shadow exposure alone will fall. Now, this isn't definite proof, but the full answer has to do with the same elements such as luminance range, shadow exposure, camera exposure, and flare. The scientific paper that defines it is Safety Factors in Camera Exposure which you can find in a number of my APUG posts (which appears to allow larger file uploads).

Flare will increase and decrease with changes in the luminance range and this does change the effective film speed, but unless it's something like a back-lit situation, the difference is easily offset by variations in metering and other factors. Other film testing methods may not factor in flare, such as the Zone System. In these instances, it should be factored in separately. Also flare needs to be factored in when determining film processing.

Doremus Scudder
24-Nov-2012, 03:19
Stephen,

Thanks for your usual clarity and organization when presenting the more complicated aspects of sensitometry (at least to me). I enjoy reading your posts and have followed them here and on APUG with interest. Despite my recommending a simple approach, I really find the complexities of our craft fascinating, if often not so practical. The first graphic you posted above, with the effects of no flare and flare shows what I was referring to as a "change in curve shape," which was the change in the Camera Image curve bottom right when flare is introduced. Sorry if I confused things by misnaming; I do know that the film response doesn't change when flare is introduced.

My point about ignoring flare for practical film testing was simply that 1) there is already a flare factor built in to film speed anyway, 2) an in-camera test automatically takes flare into consideration and 3) the amount of flare introduced by typical view camera systems using modern single or multi-coated lenses is close enough to the same as to be within our practical exposure tolerances, especially if we leave a bit of a safety factor for underexposure.

@Bill

I recommended pulling the darkslide halfway so as to leave half the sheet unexposed, thus giving a larger area of film-base+fog for densitometer reading or printing.

As I mentioned in my post above, I determine film speed using a visual printing method instead of a densitometer. I print a negative with a clear area and a number of different Zone I exposures. I position the neg in the carrier leaving an empty slit for the light to pass beside one edge of the negative. I first make a test strip of the clear area of the negative and this exposure to light without negative to determine my choice for maximum black, i.e., where I can tell no difference between film-base+fog exposure and the exposure to white light (max black is another topic altogether, since lighting and visual acuity play a huge role here as well. At any rate, I choose what looks maximum black to my eyes under typical display lighting). I then print the whole neg at that exposure and see which Zone I stripe has the desired separation from maximum black (again, I'm being less quantifying here than a scientist would be). This is my film speed. I then make a series of Zone Ruler negatives on two sheets of film that contain from Zone 0 (unexposed film) to Zone X. These I develop at different times. I print these as above and see which matches N, N+1, N-1, etc. The advantage of this method is that you have prints of your own personal Zone System when you are finished.

As you see, quantification is missing from my calibration system entirely. What I do have is a tool for visualizing exposure, which is what I think the Zone System is best for anyway. I know, approximately anyway, what a particular value will look like in the final print when I meter it. I can place things where I want, change them if I want, and say "forget it" if it is apparent the shot will not deliver what I want.

Best,

Doremus

Chuck P.
24-Nov-2012, 05:27
Stephen, you've said many times that average flare reduces the log H range by 1 to 1 1/3 stops, but I'm curious what that average is in terms of average flare density on top of fb+f, would that be .02, .03, .04?

When you say that flare is built into the ISO film speed, does that mean that a no flare film test (as in what I do when contacting the tablet to the sheet in the holder) could easily render an effective film speed that equals the ISO rating? In no instance have I had the effective film speed for "N" dev differ than the box speed, of course with "plus" and "minus" times increasing and decreasing fog do change the effective speed. You've also said that flare should be factored in post film testing, if flare is already factored into the ISO speed, then how do you mean by that, adding to the effective speed?

Stephen,

Thanks for the info and I see what you mean about finding the value of flare. Perhaps a lot of the theory is getting in my way, but I'm having a difficult time pulling the answer out for the statements in blue text. I guess it's the factoring in part. Do I have it right that to factor in for flare, means that one should bump the effective speed rating up by some amount? Or, have I totally missed it?

Stephen Benskin
24-Nov-2012, 06:49
My point about ignoring flare for practical film testing was simply that 1) there is already a flare factor built in to film speed anyway, 2) an in-camera test automatically takes flare into consideration and 3) the amount of flare introduced by typical view camera systems using modern single or multi-coated lenses is close enough to the same as to be within our practical exposure tolerances, especially if we leave a bit of a safety factor for underexposure.


Doremus, I agree that for most people's testing should be kept simple to non-existent. Those who shoot large format usually wish to know more about the process. Unfortunately, most tend to overemphasis the importance of film speed and underemphasis contrast.

1. Flare is factored in only with the ISO standard or any contacted, graphed approach using either the fractional gradient method or the 0.10 fixed density method. Most personal testing is done using the Zone System which does not factor it in. This is why there's usually a 1/2 to 1 stop discrepancy between Zone System EIs and ISO speeds. This is why I tend to discourage most people testing for film speed. General purpose developers generally produce speeds at the ISO speed and for most, testing will produce inaccurate results. How flare affects film speed is a complex subject, especially for beginners, so why not just skip speed testing and work on processing first. Then see what EI setting works best for your personal shooting style.

Flare also reduces the apparent luminance range. One stop of flare will reduce a 7 stop luminance range to a 6 stop illuminace range in camera. This needs to be factored into processing determination. Flare is the reason for the discrepancy between the ISO's LER for a grade 2 paper using a diffusion enlarger being 1.05 and the Zone System's being 1.25 even though if you calculate the film's slope based on their parameters, they will produce almost identical results - approximately 0.58.

2. In camera testing of a single target produces almost zero flare. Flare is caused by the light from higher luminances scattering around the camera affecting the lower exposure values. A target with a single tone doesn't have any range to distort. Even if there were flare , if using a gray or white card, the test is based on the metered exposure and then stopped down. This does not make the card's luminance value a shadow. it's simply a mid-tone or highlight exposure stopped down, and there is little influence of flare at the mid-tone and less in the highlights. As the value of flare in any given situation is near impossible to calculate, it's preferable to test in non flare conditions. So while in camera testing can be used effectively, flare has to be factored in to produce meaningful results.

3. From my understanding lens coating has reduced flare by half. Jones found uncoated lenses to average around 2 stops of flare. Nelson in Safety Factors in Camera Exposure also drew the same conclusion. Currently it's about a stop. Kodak uses 1 1/3 stops in their calculations for recommended CIs. They used to use 1 1/4 stops but changed it because of the preponderance of 35mm cameras. That's why their recommended normal CI went from 0.56 to 0.58. And the ISO film speed standard uses around a stop. When adhering to the ISO contrast parameters, the speed point is one stop above the minimum useful gradient point, which means that even in a theoretically impossible situation of an average luminance range without flare, there will still be adequate exposure to produce a print of excellent quality.

Stephen Benskin
24-Nov-2012, 07:00
Stephen,

Thanks for the info and I see what you mean about finding the value of flare. Perhaps a lot of the theory is getting in my way, but I'm having a difficult time pulling the answer out for the statements in blue text. I guess it's the factoring in part. Do I have it right that to factor in for flare, means that one should bump the effective speed rating up by some amount? Or, have I totally missed it?

Yes, flare is factored into the contacted, ISO, sensitometric approach to determining film speed, and without flare, film speeds would be slower. Take a look at the 2 quad example. The non flare example has the shadow exposure falling a stop below the speed point. With flare, it falls around the speed point. That would effectively be a stop difference in speed. As the standard already incorporates flare, there's no need to make further adjustments to the testing results. On the other hand, flare must be factored into contrast determination.

Bill, 70's military B&W
24-Nov-2012, 07:13
Doremus, again thanks for your help. I understand why you only expose 1/2 the negative.
You wrote:

Set the film speed on the meter to half of the box speed of the film (one stop overexposure; e.g., if you are testing 400 speed film, set the meter to 200). Meter the card and place it in Zone 1. Pull the darkslide halfway and shoot (use a slow shutter speed, they are more accurate). Do the same a 1/3 stop slower than box speed (i.e., the next film speed slower than box speed, for 400 speed film that would be 320).

Develop these negatives and read them with the densitometer. Find the Zone I density that is the closest to 0.01 above FB+F without being under that value. Use that for starters. If it looks like the intermediate speed (the one that wasn't tested) is better, e.g., if the 1/3-stop under was just a bit under 0.01 above FB+F, and the one-stop over neg is way over, then use that instead."

I'll be doing that test later today, and again THANK YOU to Everyone!!!
Bill

Chuck P.
24-Nov-2012, 10:21
In camera testing of a single target produces almost zero flare. Flare is caused by the light from higher luminances scattering around the camera affecting the lower exposure values. A target with a single tone doesn't have any range to distort. Even if there were flare , if using a gray or white card, the test is based on the metered exposure and then stopped down.

All good stuff :), but....

Doing the test as described in The Negative does not involve stopping down an "in-camera" exposure of a step tablet. A uniform target is metered in diffuse light and then several sheets are exposed at Zone I at different speed ratings and a sheet is developed for fb+f, then they are read with a densitometer to find the EI that yields a 0.1D. But I don't think anyone does that anymore, way too costly in materials and time. This test, it seems, does involve a bit of flare, to whatever extent it may be.

Under Schaeffer/Ross, the test is flare free with the tablet exposed in camera to a uniformly lighted (diffuse) target-----exposed at +4 or +5 stops to arrive, with a single exposure, at the EI. Doing AA's way would take 7 or 8 sheets and lots more chemistry, and who needs that in this economy!-----well, any economy really.

Probably does not change anything but for the record, ZS testing done today should not be referrence by indicating that a step tablet is metered in-camera and then given a -4 exposure.

But back in the day, it appears to me that any veiling flare, whatever that is or is not with a diffusely lit uniform target, was somewhat accounted for in the EI if present to any significance. This is indeed what AA described, be he right or be he wrong-----but his work speaks for itself in either case.

Bill Burk
24-Nov-2012, 10:25
Find the Zone I density that is the closest to 0.01 above FB+F without being under that value.

Yes but look for 0.10

Stephen Benskin
24-Nov-2012, 11:35
Doing the test as described in The Negative does not involve stopping down an "in-camera" exposure of a step tablet. A uniform target is metered in diffuse light and then several sheets are exposed at Zone I at different speed ratings and a sheet is developed for fb+f, then they are read with a densitometer to find the EI that yields a 0.1D. But I don't think anyone does that anymore, way too costly in materials and time. This test, it seems, does involve a bit of flare, to whatever extent it may be.

The impression I get is that most people who do testing still use something that is similar to the method described in The Negative. I've covered how there is a limited to zero amount of flare in traditional Zone System / in camera testing. Here's another example. It has a shorter luminance range. As you can see the amount of flare in the shadow region is smaller than in the standard model, and flare at the metered camera exposure is extremely small (it probably appears larger than it is because of the way the program displays it). Now assume a luminance range of a single tone. Even it we had an average luminance range with average flare, because the target is from the mid-tone or highlight area, it will only reflect the flare from that area, which is small for the mid-tone and almost non-existent for the highlight. In no way would it be representative of the effect of shadow flare.

And veiling flare is the term for overall flare, as opposed to ghost image flare which is the streaky type that produces images of the aperture.


84179

Bill Burk
24-Nov-2012, 15:40
Hi Chuck,

To solve the riddle why a traditional Zone System camera test is no-flare: Imagine a gray target with a small black spot in the corner. The gray target meters Zone V (naturally) and imagine the black spot meters Zone II. Shoot that target as-is with metering recommended for Zone V, and you would expect (and get) Zone V for Zone V. But one stop flare will bring up the Zone II spot as if it got Zone III. Flare hardly affects the Zone V.

Now do a stop-down speed test from the same target: The Zone V, you stop down 4 stops to place it on Zone I. Effectively you have also stopped down the black spot to Zone "minus II" (if minus Zones existed). The same amount of flare exists and would bring that black spot up to Zone "minus I" which is still effectively nothing.

In this example you have ruled out flare from the test.

Now a step target shot in camera, that's a different story. I think it would have flare.

Chuck P.
24-Nov-2012, 15:47
The impression I get is that most people who do testing still use something that is similar to the method described in The Negative.

I guess, but I can't imagine it. It would take at least 7 sheets alone just to find the EI, that is, exposing sheets in 1/3 stop increments one full stop either side of box speed as described in The Negative. Then there are the dev times for N, +1, +2, -1, -2. This is a lot of sheets and a lot of chemistry. No step tablet involved the way he did it.



I've covered how there is a limited to zero amount of flare in traditional Zone System / in camera testing.

When you say "in camera" I take that to mean you are referring to the step tablet that is contacted to the film in the holder.......if that is what you are saying, that is certainly not "traditional" ZS testing.

Stephen Benskin
24-Nov-2012, 18:28
When you say "in camera" I take that to mean you are referring to the step tablet that is contacted to the film in the holder.

No, I consider that a form of contacting. The camera is only being used as a light source. The test subject is the step tablet. For me, an in camera test is one done using the camera and an exterior (outside the camera) target.

Chuck P.
24-Nov-2012, 20:09
No, I consider that a form of contacting. The camera is only being used as a light source. The test subject is the step tablet. For me, an in camera test is one done using the camera and an exterior (outside the camera) target.

Ok, I see, thanks for clearing that up for me. But there has been in, what seems, plenty of threads, discussion of reducing exposure 4 stops while contacting a step tablet to the film, that just does not make sense, but perhaps I'm remembering poorly, IDK. Exposing a sheet of film to Zone I makes sense if only the film is in the holder, not the tablet and the film. Thanks.

Chuck P.
24-Nov-2012, 21:29
Can someone please give me the easy version of the film speed test?

IMO, that would be here (http://www.amazon.com/The-Ansel-Adams-Guide-Photography/dp/0821219561). Well worth your time, you can avoid any 1/3 stop exposure increments-----remember, the resulting curves are flare free.

Bill Burk
24-Nov-2012, 21:42
Now a step target shot in camera, that's a different story. I think it would have flare.

How soon I forget. Of course a camera shot where the subject is a step wedge taped to glass will have flare.

I had to back out the flare to get a sane curve fit on a family of curves shot this way.

But if the step wedge were placed in contact with the film, there wouldn't be flare.

I don't recall advice to stop down a step wedge exposure by 4 stops. That is what you do when shooting a gray or textured card and placing it on Zone I.

Chuck P.
25-Nov-2012, 05:25
I don't recall advice to stop down a step wedge exposure by 4 stops.

I think, Bill, I was connecting Stephen's referrences to "in camera" to specifically mean a referrence to the step tablet being "in camera", but he clearly states that was not the case now. Then, when discussion of stopping down 4 stops was occurring, I mistakingly linked those together and it always confused me.

macandal
25-Nov-2012, 11:20
IMO, that would be here (http://www.amazon.com/The-Ansel-Adams-Guide-Photography/dp/0821219561). Well worth your time, you can avoid any 1/3 stop exposure increments-----remember, the resulting curves are flare free.Well, in "The Negative," he, Ansel Adams, does the film speed test using third stops. He changes his way of doing it for this book? In this one he's full stops? This one's at my library. I'll check it out.

Bill Burk
25-Nov-2012, 13:03
Well, in "The Negative," he, Ansel Adams, does the film speed test using third stops. He changes his way of doing it for this book? In this one he's full stops? This one's at my library. I'll check it out.

I think the advice from Doremus Scudder (make only a few test sheets - some 1/3 stop, some full stop) is wise. I don't believe Ansel Adams changed his advice book to book, but let us know when you check it. I think Chuck's suggesting something like Doremus... just make a few tests at full stop increments.

I am intrigued that there are at least three possible "in-camera" tests, with or without flare for different reasons: 1) Subject is a test wedge taped to glass lit from behind [flare included] 2) Subject is a test wedge taped to film but using the camera to control the light [no flare, contacted] 3) Subject is a monotonous textured surface [no flare, stopping-down 4 stops makes flare insignificant - Ansel Adams' way].

Easy to get confused, but so simple when you lay it out.

mandoman7
25-Nov-2012, 14:21
I use the board that Gordon Hutchings describes in his pyro book with good results. The advantage being that all 10 zones are exposed on one sheet. Since the board is narrow, I like to expose a half sheet with the board and the other half with an outdoor scene using a splitter. That way the measured values can be compared to a actual image. The irony is that the indexes almost always came out to 64 for the 100 Asa films and160 for the 400 Asa films.

Chuck P.
25-Nov-2012, 16:34
I think the advice from Doremus Scudder (make only a few test sheets - some 1/3 stop, some full stop) is wise. I don't believe Ansel Adams changed his advice book to book, but let us know when you check it. I think Chuck's suggesting something like Doremus... just make a few tests at full stop increments.

I am intrigued that there are at least three possible "in-camera" tests, with or without flare for different reasons: 1) Subject is a test wedge taped to glass lit from behind [flare included] 2) Subject is a test wedge taped to film but using the camera to control the light [no flare, contacted] 3) Subject is a monotonous textured surface [no flare, stopping-down 4 stops makes flare insignificant - Ansel Adams' way].

Easy to get confused, but so simple when you lay it out.

How I do it is by your #2 (sliding a 4x5 tablet on top of a 4x5 film in the film holder), but the actual "subject" is a uniform test target (not textured) such as a mat board taped to an outside wall (in open shade or uniform overcast day light), with the camera at inifinity (no bellows draw) and close enough to the target to fully cover the GG---it's essentially photographing an extremely blurred image of the mat board through the step tablet. So, the way I see it, the subject is not the step tablet, but the recording of a uniform exposure through the tablet to the film.

Or, it can be described like #3, monotone target (again, no textured surface) but not stopping down 4 stops, rather exposing the tablet at +5, a Zone X exposure that is stepped down by 21 steps to generate the curve---it's the method in Schaeffer's book.

Bill Burk
25-Nov-2012, 18:06
How I do it is by your #2 (sliding a 4x5 tablet on top of a 4x5 film in the film holder), but the actual "subject" is a uniform test target (not textured) such as a mat board taped to an outside wall (in open shade or uniform overcast day light), with the camera at inifinity (no bellows draw) and close enough to the target to fully cover the GG---it's essentially photographing an extremely blurred image of the mat board through the step tablet. So, the way I see it, the subject is not the step tablet, but the recording of a uniform exposure through the tablet to the film.

Or, it can be described like #3, monotone target (again, no textured surface) but not stopping down 4 stops, rather exposing the tablet at +5, a Zone X exposure that is stepped down by 21 steps to generate the curve---it's the method in Schaeffer's book.

Yours is purely my example 2) A no flare test because with the step wedge in contact with the film, there is no way for "light pollution" from the bright patches to sneak past the darkest patches of the step wedge.

You do the right thing, an even source of controlled light... give enough exposure to hit Zone X... Step wedge gives you 21 steps down from Zone X, at half stop per step, takes you down to Zone 0.

But if the step wedge is on glass outside the camera, light pollution is going to mess with your Zone 0 and Zone I. It will be like the whole sheet got Zone I exposure.

Chuck P.
26-Nov-2012, 06:25
But if the step wedge is on glass outside the camera, light pollution is going to mess with your Zone 0 and Zone I. It will be like the whole sheet got Zone I exposure.

Exactly, but I can recall Ralph L. suggesting taping it to a window, always thought that was kind of odd.

Doremus Scudder
26-Nov-2012, 06:47
Here's my method, which takes flare into account:

I find a dark subject, or use a black card. This is placed in a scene with other values, but takes up at least 25-30% of the area of the negative. Always some Zone VIII or IX whites in the scene as well. this gives me a rather average amount of flare.

I, too, focus the camera at infinity, even though much of the scene is much closer. I try to have the dark subject run vertically along one side of the negative (or horizontally longwise along an edge).

For a film test, I have a method with which I can make 5 stripes (4 exposures and one unexposed stripe) on one sheet of film in 1/3 or 2/3-stop increments. This, of course, requires multiple exposures and pulling the darkslide a bit between each (I have a darkslide with marks on it for just this purpose), which does introduce the intermittency effect. This, however, I ignore; another thing I consider inconsequential for this kind of down-and-dirty testing.

I make my 4 exposures at between box speed and one stop overexposed in 1/3-stop increments for films I am already familiar enough with (or am retesting) to know my E.I. will fall in that range. Otherwise, I make exposures between 1 1/3 stop under to 1/3 stop over relative to box speed in 2/3 stop intervals.

I develop the negative for N or for an extrapolated N. These I print in my enlarger as described above. I find max black and then note the stripe that gives me a Zone I exposure. This becomes my working film speed for contrast testing.

For contrast testing, I make two sheets with five stripes each from Zone 0 through Zone IX using a similar target to that described above. It's easy to make a several sets of these at once. One set gets developed at N and printed. If it is not a good N, I make a change in developer time and repeat till I get my N. The same for N+1, N-1 (-2, -3, -4). I don't like to expand more than N+1. I use SLIMT techniques for achieving up to N-4. I haven't ever had reason to contract more than that; usually, N-2 plus a bit of soft print developer or flashing is all I really want to use for contrasty outdoor scenes.

Note that my tests use no densitometer. They take in camera flare into considerations as well as flare from the enlarger. I used to do the test by contact printing, but enlarger flare is a significant enough factor to have made me change to enlarging my test negs. Also note that I don't shoot boxes of film to make the tests. From zero through film speed test to N, N+1, N-1 and N-2 would only take 16 sheets total in the worst case. Often, it takes much less film. I tested out T-Max 400 recently with 8 sheets and have a usable N, N+1, N-1 and N-2.

For me, the contrast testing is most important. Nevertheless, I do not hesitate to use higher contrast paper or VC paper at a high contrast filtration for many images. In fact, I often designate N development and grade 3 paper, since I like the look of this combination (more local contrast, more highlight separation).

My method is empirical, but gives me information about what to expect with my system from metering through enlarging. It uses only equipment that I actually use to make photographs. Best for me, it is strictly visual and helps me have a mental image of what tonality will appear on my final print when my meter says "X" and I decide to develop "Y."

Best,

Doremus

macandal
26-Nov-2012, 14:32
I was getting ready to do the test, and it just occurred to me ... how do you focus to infinity on LF? Thanks.

Andrew O'Neill
26-Nov-2012, 15:24
I use the board that Gordon Hutchings describes in his pyro book with good results.

I've used this method for many years. All zones on one sheet of film. Cuts way back on film waste. Very easy to construct/set up.
Macandal, do your test in 1/3 stop increments. To focus at infinity, just point your camera at something far, far away and focus on it. Then swing the camera back to your test target. Good luck!

Chuck P.
26-Nov-2012, 16:32
I was getting ready to do the test, and it just occurred to me ... how do you focus to infinity on LF? Thanks.

A LF lens is focused at infinity, good enough, when the lens board (technically the rear nodal point of the lens, I believe) is one focal length from the film plane----ex: for a 210mm lens, infinity focus is when the lens board is 210 mm from the film plane.

macandal
26-Nov-2012, 16:44
A LF lens is focused at infinity, good enough, when the lens board (technically the rear nodal point of the lens, I believe) is one focal length from the film plane----ex: for a 210mm lens, infinity focus is when the lens board is 210 mm from the film plane.So, my 180mm lens should be 180 mm from the film plane, right?

Thanks, Chuck and Andrew.

Chuck P.
26-Nov-2012, 17:06
So, my 180mm lens should be 180 mm from the film plane, right?

Thanks, Chuck and Andrew.

Yep, one focal length from the film plane. Don't know what camera you have, but I think it's good to know what length between the front and the back is needed to quickly put the lens at infinity. I have a monorail that I use in the field, it has a mm scale on the rail---with the lens at infinity for my 120mm Nikon for example, I've determined that from the inside of the front standard to the inside of the back standard, there needs to be just 30mm showing on the rail, for my 210mm, it needs to be 126mm inside to inside. If bellows draw is a concern for determining exposure, I know by how much by seeing if the inside distance is farther than 30mm for the 120 and farther than 126mm for the 210. When the bellows extension is far enough to be at least a factor of 1.5x (or 2/3 stop), then I'll make the needed adjustment to the exposure.

But, of course, for the purpose of film testing, you don't want bellows draw to come into play, so know where infinity is with your camera/lens.

Rafal Lukawiecki
26-Nov-2012, 17:52
Exactly, but I can recall Ralph L. suggesting taping it to a window, always thought that was kind of odd.

I wouldn't advise taping the wedge to a window, flare will make the curves almost useless. See this recent thread (http://www.apug.org/forums/forum37/109334-film-testing-wbm-curves-320txp-xtol-1-1-too-contrasty-how-did-i-mess-up.html) for a detailed account of my film testing experience, plus help from Bill, Stephen, and others, in making sense out of it.

Stephen Benskin
26-Nov-2012, 19:31
Rafal, you beat me to it. I was going to reference that thread.

Whatever type of testing anyone wishes to do depends on what they want out of it. Doremus' approach is effective and it will produce good printable negatives, but it is difficult to communicate details and results to others. Other methods quantify the results allowing for precise exchange of information, but the methodology can be too abstract, time consuming, and difficult to learn. I personally follow the second approach but it took time to get to a comfortable level. As I worked toward understanding theory, I continued to get good negatives in most cases using something similar to the first approach. There is another approach that I do have a problem with and that is the one that claims precise and quantifiable results but is full of wrong assumptions and sloppy methodology.

Bill Burk
26-Nov-2012, 21:56
Whatever type of testing anyone wishes to do depends on what they want out of it. Doremus' approach is effective and it will produce good printable negatives.... Other methods quantify the results...

As Doremus implied, there is a certain elegance in using what you have on hand to test and taking to the enlarged print to prove end-to-end that it works. I have my comfort level with pre-press experience that makes me feel like I am hanging out with old friends when I use test strips and densitometers. I encourage anyone to take the journey, whatever approach.

Chuck P.
27-Nov-2012, 05:04
I encourage anyone to take the journey, whatever approach.

Like most, I took it with just a camera, a step tablet, and a densitometer. But the results in making negatives has been a giant, giant, giant leap from what I was doing before I learned to do EI and development time testing via The Negative first, then more economically via Schaeffer, also learning about factoring in flare has been really beneficial---I don't apply anything uniformly, but rather I take it one exposure at a time.

Rafal Lukawiecki
27-Nov-2012, 05:07
Having been on the film testing journey for a short time in comparison to how long I have been involved in B&W photography, I can already endorse, without hesitation, what I read from Stephen's, Bill's, and Doremus's posts, ie. that this testing experience is about discovering, and internalising, how the entire tone reproduction process works, from a scene, to the image on paper. Books on the subject, like BTZS by Davis, seem to arrive at the same conclusion.

In my experience, I still do not have a 100% precise personal EI, and my negative development times are not 100% perfect either—but I am already in the 85% target range, 80% of the time, based on my selection of paper and burn grades. Above all, I have a good feeling for what the different curves mean, and I am applying this knowledge at the taking stage, when I am with my camera in the field. I expect it will take me a few more years, before it becomes a second nature, by which time I might find a precise EI, but I probably won't care for it as much. I understand what Michael meant, when he was referring to thinking about the curve, rather than specific CIs, gradients, and an EI.

One way, or another, my humble advice to the OP would be to do the testing by whatever feels comfortable whilst removing variables (such as flare) just to get started on this journey. Personally, I have found more comfort in testing for the development times and contrast first, then the EI, but I am sure the other way round would be as fruitful in the end, as attested by others.

Stephen Benskin
1-Dec-2012, 13:20
I ran across a quote that I thought was quite fitting, "In the matters of taste, there can be no disagreements." The quote is very appropriate for a personal choice of a developmental method. On the other hand, debating whether the elements of that method are scientifically sound, repeatable, logical, realistic, and other matters of proof are not only appropriate but essential. The point where many good threads fail is when the distinction between the two gets blurred.

Doremus Scudder
2-Dec-2012, 04:45
I ran across a quote that I thought was quite fitting, "In the matters of taste, there can be no disagreements." The quote is very appropriate for a personal choice of a developmental method. On the other hand, debating whether the elements of that method are scientifically sound, repeatable, logical, realistic, and other matters of proof are not only appropriate but essential. The point where many good threads fail is when the distinction between the two gets blurred.

Well said, Stephen!

Bill Burk
2-Dec-2012, 18:57
In my experience, I still do not have a 100% precise personal EI, and my negative development times are not 100% perfect either... I expect it will take me a few more years, before it becomes a second nature...

Thanks for the praise, but you're a student who'se surpassed the teacher...

A precise EI is only necessary when you want to get the absolute highest possible quality. Or if you want to have the absolute fastest shutter speed for a situation. Because when it comes to landscapes on LF, I've gotten good prints from negatives when I rated TMY-2 (nominally 400) at 64. (This was due to a gross error in testing. I vignetted my speed test.)

Doremus Scudder
3-Dec-2012, 04:07
Bill,

I might submit that slightly (or more) overexposed for some films can actually result in better overall quality. 320 Tri-X has a really long sloping toe. When I want to emphasize separation in the shadows, I'll add a stop (sometimes more) to the exposure to get the shadows farther up onto the straight-line portion of the film curve. I have a couple of negatives that proper-proof almost white, but yield great prints with lots of low-value detail. I use this technique especially with subjects that I plan to print on grade 3 or higher paper and are less-developed than they might be.

This is more optimizing subject brightnesses to the film curve, and not really film-speed testing, but does point out that a minimum exposure is not always the best.

Best,

Doremus

Rafal Lukawiecki
3-Dec-2012, 07:11
Thanks for the praise, but you're a student who'se surpassed the teacher...

A precise EI is only necessary when you want to get the absolute highest possible quality. Or if you want to have the absolute fastest shutter speed for a situation. Because when it comes to landscapes on LF, I've gotten good prints from negatives when I rated TMY-2 (nominally 400) at 64. (This was due to a gross error in testing. I vignetted my speed test.)

Bill, thank you for your kindness, though I am sure I have not deserved it. I look forward to making my own EI-related mistakes, and learning from them, as much as I look forward to learning from you, and from other experienced souls on LFPP and APUG. You have been very helpful guiding me through the matter of plotting curves, and Stephen has made sense out of them, and the flare. Altogether, I think you have saved me many months of frustration—I hope to pass the savings onto others who are at the beginning of this process.

macandal
21-Feb-2013, 09:40
So, it's taken me longer to do this film speed test. Life happens and you know how that is. Anyway, yesterday I was finally ready to do it. Loaded my film, set my camera to infinity, got my gray card ready, but then I couldn't get the whole card to fill my shot. Not even 80% of it. And to do so, I had to get really, really, close. Like 2 feet close (lens to card). That's when I stopped because I figured being that close could not be good (i.e., I may had been casting some shade on the card, etc), or that I was doing something wrong by not being able to get my camera to get the whole card. How do you guys do it? My card is 8x10, do I need a bigger card? Do they even exist? Can you guys help? Thanks.

premortho
24-Feb-2013, 18:08
Bill......is that a foot candle?
YEAH!!!!!!!! finally, a light comes on, it's a weak candle flame, but I'll do my best to keep it burning,
Thanks to everyone, and I'll be working on it this weekend.
Bill

Kevin J. Kolosky
24-Feb-2013, 19:11
So, it's taken me longer to do this film speed test. Life happens and you know how that is. Anyway, yesterday I was finally ready to do it. Loaded my film, set my camera to infinity, got my gray card ready, but then I couldn't get the whole card to fill my shot. Not even 80% of it. And to do so, I had to get really, really, close. Like 2 feet close (lens to card). That's when I stopped because I figured being that close could not be good (i.e., I may had been casting some shade on the card, etc), or that I was doing something wrong by not being able to get my camera to get the whole card. How do you guys do it? My card is 8x10, do I need a bigger card? Do they even exist? Can you guys help? Thanks.

First of all, you don't need to use a kodak gray card. You can use any larger card that is close. Remember, your reflective meter is telling you what exposure you need to make for the card to be 18 percent gray. It doesn't really care what you start out with - its still going to measure for 18 % gray.

but if you want to use your gray card and get closer you need to account for bellows draw in your exposure calculations. You need to account for the light loss that is measured by the inverse square law. you can take the square of the focal distance over the focal length and multiply the shutter speed by that figure.

So, for example. Your meter gives you a reading of f8 at 1 sec. and you are using an 8 inch lens and you have the bellows racked out to 11 inches.

11/8 squared is about 1.9. 1.9 x 1 equals 1.9 seconds, or about 1 stops more exposure.

Bill Burk
24-Feb-2013, 22:02
As Kevin said, it doesn't have to be 18% gray, since whatever it is... you will meter it.

You could get a sheet of matt paper that's about the same gray and then shoot it from several feet away, filling the frame.

Or you could shoot the graycard you have from several feet away. You will have a patch that your densitometer can read.

Rafal Lukawiecki
25-Feb-2013, 04:42
Having done several types of film tests recently, including some failed ones, I would suggest it may be easier to have a large, uniform sheet that fills the frame, rather than a smaller one, due to the risk of flare compressing your results. Flare can give you a whole f/stop of a difference. What matters is what would be behind, or around, the smaller sheet, especially if it was of a much different, or even changing luminance, compared to the smaller sheet, throughout your test. If this is of interest to you, I suggest looking up at a good few posts about the issues of flare affecting film testing, primarily impacting contrast/development time tests. It is quite fascinating. Nonetheless, you have a lot of good advice here.

Brian Ellis
25-Feb-2013, 09:44
So, it's taken me longer to do this film speed test. Life happens and you know how that is. Anyway, yesterday I was finally ready to do it. Loaded my film, set my camera to infinity, got my gray card ready, but then I couldn't get the whole card to fill my shot. Not even 80% of it. And to do so, I had to get really, really, close. Like 2 feet close (lens to card). That's when I stopped because I figured being that close could not be good (i.e., I may had been casting some shade on the card, etc), or that I was doing something wrong by not being able to get my camera to get the whole card. How do you guys do it? My card is 8x10, do I need a bigger card? Do they even exist? Can you guys help? Thanks.

When you say you couldn't get the card to fill the frame, keep in mind that for this purpose the card shouldn't be in focus. So it really shouldn't matter what lens you use or how big the card is, you should be able to fill the frame with almost any lens if you get close enough because you don't need (and in fact don't want) the card to be in focus.

However, your point about casting a shadow if you get too close is a valid point. To check it set the camera and card up in a manner such the frame is filled with the card, then meter the corners and center of the card with a spot meter to make sure you get the same readings all the way around. Actually that's a good practice to follow even if you're not concerned about being too close.

macandal
25-Feb-2013, 11:24
When you say you couldn't get the card to fill the frame, keep in mind that for this purpose the card shouldn't be in focus.It wasn't. I set it to infinity first. I focused at something some 50 feet in the distance, then I was trying to get the whole card in my shot.

macandal
25-Feb-2013, 11:29
First of all, you don't need to use a kodak gray card. You can use any larger card that is close. Remember, your reflective meter is telling you what exposure you need to make for the card to be 18 percent gray. It doesn't really care what you start out with - its still going to measure for 18 % gray.I was thinking of using the big blocks (columns) of concrete that one sees under freeways. Those are nice and gray and big enough to fill my whole shot.

Kevin J. Kolosky
25-Feb-2013, 11:54
By the way, I am kind of wondering why you would want to use a gray card anyway. Everytime I do film testing I use a black card. What I am looking for is .10 above film base plus fog.

Stephen Benskin
26-Feb-2013, 20:19
Depending on how precise the test needs to be, it can matter what the camera points at. Different materials reflect the various wavelengths differently. This graph is from the Kodak Cray Card. It's missing the infrared and ultraviolet response which can be important as they can unknowingly influence the test. Just something to keep in mind.

90267

Tim Meisburger
26-Feb-2013, 22:04
I used a flat wall. Just figure out the area your lens sees, and then use your spotmeter to check that every part of that area is evenly illuminated (i.e. reads the same).

Kevin J. Kolosky
2-Mar-2013, 07:10
If you want to do a "visual" film speed test rather than using a densitometer and graphs and all that goes with it you could try this.

Go to the corner of a large building on a sunny day. Make sure one side of the building is in shade, and one side is in direct sun.
Place something that is black in the shade.
Place something that is quite light but has texture in the sun.
Meter the dark object for zone 1 and shoot the photo.
Develop as recommded.
Using your paper, find its minimum time for max black by printing a blank negative.
print your negative for the same exposure. Look for the black to be just slightly lighter than the blank negative black. Make adjustments to exposure if necessary. (too black give more exposure, too light give less exposure) (i.e. change ISO)
At the same time, look at the very light object. If its blank white the neg is too dense and you need to develop less. If its too dark the neg isn't dense enough and you need to develop longer.

You can tinker around with this until you get it looking the way you want it to look. Just make sure you write down everything you did so you don't forget what you did because once you find the combination that looks right to you then you are going to want to do it the same way each time. (temp. for development, ISO of film, etc.) And you can think of changing the time or aperture when exposing film as changing the ISO.

Now you have calibrated your camera and your film to your paper based on your eyes in a situation that cannot have any more stops difference between light and dark.

Remember, in most cases the paper is the limiting factor, not the film.

macandal
2-Mar-2013, 14:04
Thanks. I shot it. Developed it. Now I'm trying to figure out how to use the densitometer. The instructions are crap and hard to follow because they omit steps. It's an X-Rite 810. First of all, I'm trying to calibrate it but, as I said, the instructions are pretty bad. People at the place where I'm using the densitometer (RayKo in San Francisco) are trying to help me but they can't figure it out either. So, if anyone can give me step by step instructions I would appreciate it. Thanks.

Kevin J. Kolosky
2-Mar-2013, 15:03
I don't know how an X-Rite works, but I would think it couldn't be too much different than any other densitometer.

First you would want to Zero it out. Then you would want to go to the black and white channel (on my McBeth its called the Visual channel) and measure a known test strip to see if the thing is working correctly.

After that you replace the test stip with the film and make your readings.

Take a look here.

http://www.largeformatphotography.info/forum/showthread.php?99047-X-Rite-810-Questions

If worse comes to worse, you can send your negs to me and I will read them for you.

macandal
2-Mar-2013, 19:20
I don't know how an X-Rite works, but I would think it couldn't be too much different than any other densitometer.

First you would want to Zero it out. Then you would want to go to the black and white channel (on my McBeth its called the Visual channel) and measure a known test strip to see if the thing is working correctly.

After that you replace the test stip with the film and make your readings.

Take a look here.

http://www.largeformatphotography.info/forum/showthread.php?99047-X-Rite-810-Questions

If worse comes to worse, you can send your negs to me and I will read them for you.Yes, I think I'm doing it right. By the way Kevin, that link, that was me asking how to use the densitometer.

Well, the problem I'm now having is that after doing all my readings (subtracting FBF from the density from each of my exposures to get the net density), getting my results, I get nothing, anywhere near 0.1 density. The closest I get is 0.02! Agggh...! What the hell is going on???

Kevin J. Kolosky
2-Mar-2013, 21:49
could you go over your exact shooting and developing procedure for those negs. what was your film base plus fog reading? what was the reading for each of your negs.

macandal
3-Mar-2013, 13:55
could you go over your exact shooting and developing procedure for those negs. what was your film base plus fog reading? what was the reading for each of your negs.I went to an art supply store and bought a large gray board. As close to a "gray card" as I could get it. Stuck it to a wall with a shade. I focused my camera (4x5) to a place some 50-70 feet in the distance, then I turned the camera in the direction of the gray board (a distance of about 2-3 feet). I took a reading of the card and it said f5.6/'60 (this, of course, is Zone V). Then the instructions said to begin a series of exposures with a Zone I starting point:


1. No exposure==0.08 density
2. Zone I==f22=='60==0.09 density==0.01 net density
3. 1/3 stop less from #2==f22 1/3=='60==0.09 density==0.01 net density
4. 2/3 stops less from #2==f22 2/3=='60==0.09 density==0.01 net density
5. 1 stop less from #2==f32=='60==0.08 density==0 net density
6. 1/3 stop more from #2==f16 2/3=='60==0.08 density==0 net density
7. 2/3 stops more from #2==f16 1/3=='60==0.09 density==0.01 net density
8. 1 stop more from #2==f16=='60==0.1 density==0.02 net density

This is the method that Ansel Adams describes in his book "The Negative" the closest net density value to 0.1 is the appropriate ASA for your film. As you can see, the closest I get to 0.1 was my last shot (#8) at 0.02--that's not even close.

Any ideas? Thanks.

Stephen Benskin
3-Mar-2013, 16:34
If you shot it like you say, my first response is the film was way under processed. Was there anything processed other than the "speed" test.

macandal
3-Mar-2013, 16:41
If you shot it like you say, my first response is the film was way under processed. Was there anything processed other than the "speed" test.No. Nothing. Just the 8 sheets you see above for the 7 minutes this particular film called for. By the way, I forgot to mention this was Arista Ultra EDU 100 ASA.

Corran
3-Mar-2013, 17:01
60 seconds?? For Zone I, that means your Zone V exposure would be 16 minutes! You are probably not getting anything due to reciprocity effects. Actually light your card so your exposure isn't more than 1 second so you can eliminate that issue.

macandal
3-Mar-2013, 17:09
60 seconds??'60 = 1/60th of a second.

Corran
3-Mar-2013, 17:12
Ah okay, never seen it written like that.
Either way it sounds like you have no exposure on that film.
I haven't read all 10 pages of this but I would not be shooting a test with 1/3 stop differences. When I've done speed tests I've shot like 5-6 shots each 1 stop away different.

Chuck P.
3-Mar-2013, 17:21
It's as if you developed 8 sheets with essentially no exposure recorded at all, save #8 with maybe just a bit of exposure, IDK.

Brian Ellis
3-Mar-2013, 18:02
There's no way I can think of that you could be getting the readings you got, assuming that you're correctly using the manufacturer's suggested speed and development time, unless the densitometer is malfunctioning or isn't being used correctly or the light was changing between your exposures. Maybe there are other ways but if so I can't offhand think of what they might be. When you develop each sheet of film you are using the same agitation method for each sheet and keeping the developer temperature constant for each sheet, right?

If you want to try another method, you could use this one, which I think is a little simpler than Adams' method.

After determining fb+fog as you did above, set the film speed on your meter to the manufacturer's stated speed. Take a reading of the card (your Zone V reading) using an aperture that will allow you to use a mid-range shutter speed (i.e. not the two fastest speeds and not the two slowest). Reduce that aperture reading by four stops (Zone 1) and make your first exposure. Then change the speed setting on the meter to double the manufacturer's stated speed, take a reading, reduce the aperture by four stops, and make a second Zone I exposure. Make a third Zone I exposure at about 75% of the stated speed and a fourth at half the stated speed. After development find the sheet that has a density of .08 to .10 above film base plus fog. That's your film speed.

You might try this method and compare the readings you get with it to the readings you got using Adams' method. If they're the same or close to the same then making the assumptions I made above one of the problems I mentioned above must exist.

At this point you will have gone through most of a 25-sheet box of film so things will be getting expensive and frustrating if you still aren't getting realistic readings. At that point I'd just forget doing the tests yourself and contact The View Camera Store - www.viewcamerastore.com - and let them send you the film that you'll develop per their instructions and from which they'll then give you more and probably better information about film speeds and development times than you can get yourself. The cost is about $30 and well worth it IMHO.

Brian Ellis
3-Mar-2013, 18:12
60 seconds?? For Zone I, that means your Zone V exposure would be 16 minutes! You are probably not getting anything due to reciprocity effects. . . .

No. He isn't getting his Zone I exposures by changing the shutter speed from his Zone V reading. He's leaving the shutter speed at the speed he used for Zone V and getting his Zone I exposures by changing the aperture, which is the correct way to do it.

Corran
3-Mar-2013, 18:19
The point is moot since he was talking about a 1/60th shutter speed, BUT - that's irrelevant. My point was that for a Z1 reading to be 60 seconds, that means a "correct" exposure for Z5 would be 16 minutes, which is way into reciprocity problem area, hence the low values like Z1 getting lost due to reciprocity failure. Or yes he could shoot with a wider aperture but I was thinking he did his exposures at 60 seconds, hence causing the problem.

Brian Ellis
3-Mar-2013, 19:09
The point is moot since he was talking about a 1/60th shutter speed, BUT - that's irrelevant. My point was that for a Z1 reading to be 60 seconds, that means a "correct" exposure for Z5 would be 16 minutes, which is way into reciprocity problem area, hence the low values like Z1 getting lost due to reciprocity failure. Or yes he could shoot with a wider aperture but I was thinking he did his exposures at 60 seconds, hence causing the problem.

His "correct exposure" for Zone V was never 16 minutes (or the equivalent if '60 means 1/60 as stated above). He stated his "correct exposure" as f/5.6 and 60 (or 1/60 if '60 means 1/60 as stated above) seconds. He gets from that correct Zone V exposure to his various Zone I exposures by changing the aperture and leaving the shutter speed constant at the shutter speed used for his "correct exposure." At no point is a 16 minute exposure (or the equivalent Zone V exposure if '60 means 1/60) relevant to anything.

Corran
3-Mar-2013, 19:28
There is no need to write a diatribe. I thought he meant 60 seconds was his exposure time, as I clearly wrote in my first/second post. I then corrected myself when he explained what he meant by '60.

That's all there was to it!

Brian Ellis
3-Mar-2013, 19:43
There is no need to write a diatribe. I thought he meant 60 seconds was his exposure time, as I clearly wrote in my first/second post. I then corrected myself when he explained what he meant by '60.

That's all there was to it!

Diatribe? Sorry, I certainly didn't mean it that way and if you took it that way my apologies. I too originally thought he meant 60 seconds. That apparent mistake on both our parts didn't seem to be the point of your messages but perhaps I misunderstood them.

Corran
3-Mar-2013, 19:49
Gotcha. I think I'm misunderstanding your misunderstanding of my misunderstanding :p

Kevin J. Kolosky
3-Mar-2013, 22:00
Well, of course not being there I can't say for sure where things went wrong, but I will say that I have never had a film with a film base plus fog of only .08. Maybe others have, but my readings have usually been higher than that. Which really makes it a puzzle because you had no exposure whatsoever on that negative.

Whenever you have a problem in photography you need to isolate each part of it or you'll never get anywhere.
So either your meter is bad, your film is bad, your development is bad, your shutter is bad, or the densitometer is bad.

1. Are you sure you put the proper ASA/ISO into your meter to start with.
2. I would use 1/2 stop increments
3. How did you decide on the development you gave. Is that a published formula. Was it fresh developer?
4. You should just measure your bellows for the focal length of your lens. Did the shutter speeds sound correct?
5. Have you ever had your meter calibrated before. What kind of meter is it.
6. Are you sure the densitometer is working correctly.
7. Was your development temperature correct. Is the thermometer you used calibrated?

In other words, start checking one thing at a time.

if you only had .01 density difference between F22 and F32 (a stop difference in exposure) either the light changed, you got the two negs mixed up, or something happend to your shutter.

Bill Burk
3-Mar-2013, 22:40
Hi Mario,

Many people who perform in-camera tests like this conclude their personal EI is half the rated speed.

It wouldn't be unusual for you to find a personal EI of 50.

Because this test failed with no useful information, you should run another test with greater differences in between. Maybe just a few sheets, full stop between. For example you could take shots that would equate to (12 optional), 25, 50, 100.

When I did my first camera test, I found EI 64 for TMY-2 which has an ISO of 400. It took me a long time to realize that I caused vignetting because I had placed an electronic-shutter in front of my old mechanical view camera lens. So I know the frustration of running tests and finding zero densities.

Stephen's first guess was underdeveloping. The Massive Dev Chart shows sheet developing times of 7 minutes for D-76 stock. Did you make an obvious mistake like taking a 35mm time? What developer/concentration did you use? Did it get cold? How did you develop? With trays and shuffling, I often find my developing times are longer than most charts. Most of the time I develop sheet film (TMY-2) in D-76 1:1 for 11.5 minutes even though Massive Dev chart says 9.5 minutes.

You can make a rough EI estimate first, do some developing times tests, and then when you have good developing times, repeat the 1/3 stop series closely surrounding the EI you roughed out.

macandal
4-Mar-2013, 10:39
Because this test failed with no useful information, you should run another test with greater differences in between. Maybe just a few sheets, full stop between. For example you could take shots that would equate to (12 optional), 25, 50, 100.So, using my actual test, above, as a starting point, you're suggesting I shoot:

If the actual reading of the card (Zone V) says f5.6 1/60, then:
1. No exposure
2. Zone I==f22=='60
3. 1 stop less from #2==f32=='60
4. 2 stops less from #2==f45=='60
5. 3 stops less from #2==f64=='60
6. 1 stop more from #2==f16=='60
7. 2 stops more from #2==f11=='60
8. 3 stops more from #2==f8=='60

Something like that? I realize that shots 4 and 5 may be a bit too much, but I just wanted to go up and down zone I an equal number of stops (my lens only goes down to 45 anyway).

Or maybe do I shot per zone? I don't know if this would be useful at all, but I'm willing to try anything that will yield an actual (conclusive) result.


Stephen's first guess was underdeveloping. The Massive Dev Chart shows sheet developing times of 7 minutes for D-76 stock. Did you make an obvious mistake like taking a 35mm time? What developer/concentration did you use? Did it get cold? How did you develop? With trays and shuffling, I often find my developing times are longer than most charts. Most of the time I develop sheet film (TMY-2) in D-76 1:1 for 11.5 minutes even though Massive Dev chart says 9.5 minutes.I was doing Arista EDU Ultra 100 with D-76 (stock). Both the massive dev chart and the film instructions say that with that combination, I should develop for 7 minutes, which is what I did. Hmmm...?

macandal
4-Mar-2013, 10:46
I want to throw this out to anyone reading this. Has anyone done the Ansel Adams film speed testing he recommends in his book "The Negative"? That's the test I'm trying to do here and getting nowhere fast with it. Has anyone done it successfully? Can you share your experiences? Thanks.

Kevin J. Kolosky
4-Mar-2013, 13:50
If you are talking about pages 240-241 I bet most everyone here has, including me, but I doubt many people do it exactly as he did it. Nowadays if and when I do it I only make 2 negatives, one as zone 1, and one with a half stop more exposure (meaning less ASA). If its not close (to fbpf +.10) I know what to do to make it close. I think 1/3 stops for the low ISO films is a bit too narrow, and if you want to get that close you can interpolate from your test.

As you have been advised, and as Ansel himself has said, "If none of the exposures yields approximately the anticipated .10 density, check all procedures and your exposure calculations, and then look for an equipment problem like a malfunctioning shutter, incorrectly calibrated apertures, or faulty meter, and repeat the test".

macandal
4-Mar-2013, 13:58
As you have been advised, and as Ansel himself has said, "If none of the exposures yields approximately the anticipated .10 density, check all procedures and your exposure calculations, and then look for an equipment problem like a malfunctioning shutter, incorrectly calibrated apertures, or faulty meter, and repeat the test".Thanks Kevin. I did read that particular statement and, in all honesty, I can say that my equipment is functioning perfectly well, my process was right on, and I followed the instructions to the letter, which is why I'm at a loss as to what to do next? Do you think this is due to the ASA of the film I'm using? If I were using ASA 400 or something else the test would have worked out just fine and yielded actual working results? Thanks.

And yes, I was talking about the pages you mentioned.

Kevin J. Kolosky
4-Mar-2013, 15:32
Mario

If it were me, what I would do next,( if I wanted to continue to use that film and the exact same developer combination and temperature and developing time) (and because I am cheap) I would take the same card, go to the shady side of a building in mid day, put my lens at focal length focus, meter for zone 1, and give 2 stops more exposure to one negative. It doesn't make a whole lot of sense to try 1 stop more because you already did that and it didn't do anything for you. Process the film exactly the same as before, read it on the densitometer, and see where you are at. If you get the same results as before, then there will be no doubt (IMO) that something is wrong somewhere.

Second, if there are published curves for that film and developer combination I would look at them and see what the slope of the curve is. Useful to know. That film may have an unusually long toe that slopes very gradually upwards.

macandal
4-Mar-2013, 15:37
Second, if there are published curves for that film and developer combination I would look at them and see what the slope of the curve is. Useful to know. That film may have an unusually long toe that slopes very gradually upwards.Where do I find this?

Thanks for your help.

Bill Burk
4-Mar-2013, 16:27
Hi Mario,

Yes your proposed series is a good idea. It will give you effectively a test that goes down to EI 25, which is a possible result due to development. But it's best to change one thing at a time.

Kevin J. Kolosky
4-Mar-2013, 16:31
Refer to page 247 in your Adams book for an example. for your particular film and developer combination you might go to the website of either the film manufacturer or the developer manufacturer.

Chuck P.
4-Mar-2013, 19:05
I want to throw this out to anyone reading this. Has anyone done the Ansel Adams film speed testing he recommends in his book "The Negative"? That's the test I'm trying to do here and getting nowhere fast with it. Has anyone done it successfully? Can you share your experiences? Thanks.

I did this test successfully one time, performing it precisely as instructed in The Negative, no problems for me. Sorry you're having trouble with it.

But I never performed that method of film testing again because it consumes a lot of chemicals and film for my budget. I'm a big proponent of testing film for each combo that I use, but I want to maximize the film I have for photographing and use the least amount of film for determining EI and "N" development times. That said, you can achieve the same results much quicker here (http://www.amazon.com/The-Ansel-Adams-Guide-Photography/dp/0821219561) and since you have densitometer, you only need a 21 or 31 step wedge. You'll be able to determine your EI and development times from +2 to -2 with 5 to 8 sheets of film.

Stephen Benskin
5-Mar-2013, 09:22
Because there was density above film base, the exposure couldn't have been way off, but as it really didn't change over a stop of exposure, that would indicate the development was insufficient. Of course if could also mean drift with the densitometer. The range of testing exposure needs to be larger. Make it at least 2 stops. And just because the development time was correct doesn't mean something else went wrong.

I maybe be biased, but this wouldn't be a problem using a step tablet.

macandal
19-Apr-2013, 14:25
In case there's still anyone out there following my trials and tribulations, and, more importantly, who still cares about what happens, I did the Film Speed Test again and I think this time it worked. This is what happened.

After trying to figure out what could have gone wrong and arriving at the conclusion (by me) that I had followed all the steps accordingly, I suggested a new set of shots (I think I said this in post #113 (http://www.largeformatphotography.info/forum/showthread.php?97016-Film-speed-testing&p=998080&viewfull=1#post998080)). These shots would take me one more zone in either direction (it didn't much matter in the lower zone as the previous test had already taken me to zone 0; I went ahead and closed my aperture one full stop more anyway just because I'm obsessive about this sort of thing and I wanted to be damn sure about this). The previous test started at Zone I and stopped at Zones 0 and II. Well, this time I went to Zone III. My shot list and results looked like this:

My Zone V was f/5.6 @ 1/125. I kept the shutter speed constant (i.e., I didn't change it for any of the shots), only changing the f stop.


Shot 1: not exposed; just developed (my base) = 0.09 density (d)
Shot 2: f/22 = 0.1 d = 0.01 net density (nd)
Shot 3: f/16 2/3 = 0.1 d = 0.01 nd
Shot 4: f/16 1/3 = 0.11 d = 0.02 nd
Shot 5: f/16 = 0.12 d = 0.03 nd
Shot 6: f/11 2/3 = 0.14 d = 0.05 nd
Shot 7: f/11 1/3 = 0.16 d = 0.07 nd
Shot 8: f/11 = 0.09 d = 0 nd
Shot 9: f/22 1/3 = 0.09 d = 0 nd
Shot 10: f/22 2/3 = 0.09 d = 0 nd
Shot 11: f/32 = 0.09 d = 0 nd
Shot 12: f/45 = 0.09 d = 0 nd

The results I had shot before (shots 1-5 and 9-11) are pretty comparable. Shot 12 was to be expected and so I didn't shoot in thirds of an aperture stop after shot 11 (again, I wanted to be damn sure). As someone pointed out, though, the fun happens in shots 6 and 7, where my density starts going up and gets much closer to 0.1. The head scratcher is shot 8. Why, all of a sudden, did the density go down here? From (shots) 3 to 7, the density was climbing, then, on 8, it dropped. There was nothing different done while shooting this. They were shot in the number I described above, so I expected the number to be higher and therefore, much closer to 0.1. I really don't know what happened there. Maybe shot 7 shows this particular film at its highest density? I don't know. In any case, shot 7 brings me to an ASA of 32. Rounding this number to the closest lower ASA number (if I understood Ansel Adams correctly), this means that with this particular film-lens-film combo, I have to shoot as though it were a 25 ASA film. Is my assumption correct?

What do you guys think?

Thanks.

md99
19-Apr-2013, 18:58
I would recommend acquiring a copy of Beyond The Zone System by Davis. It lays it all out fairly neatly, though you will need to buy a (not very expensive) step wedge.
+1
Don't bother with Adams' method. Davis method is much superior.
You do not need to test for each lens or each aperture. Film speed is determined by 1. film type and 2. development (developer type, time).
Cheers!

Bill Burk
19-Apr-2013, 19:27
In case there's still anyone out there following my trials and tribulations, and, more importantly, who still cares about what happens, I did the Film Speed Test again and I think this time it worked. This is what happened.

After trying to figure out what could have gone wrong and arriving at the conclusion (by me) that I had followed all the steps accordingly, I suggested a new set of shots (I think I said this in post #113 (http://www.largeformatphotography.info/forum/showthread.php?97016-Film-speed-testing&p=998080&viewfull=1#post998080)). These shots would take me one more zone in either direction (it didn't much matter in the lower zone as the previous test had already taken me to zone 0; I went ahead and closed my aperture one full stop more anyway just because I'm obsessive about this sort of thing and I wanted to be damn sure about this). The previous test started at Zone I and stopped at Zones 0 and II. Well, this time I went to Zone III. My shot list and results looked like this:

My Zone V was f/5.6 @ 1/125. I kept the shutter speed constant (i.e., I didn't change it for any of the shots), only changing the f stop.


Shot 1: not exposed; just developed (my base) = 0.09 density (d)
Shot 2: f/22 = 0.1 d = 0.01 net density (nd)
Shot 3: f/16 2/3 = 0.1 d = 0.01 nd
Shot 4: f/16 1/3 = 0.11 d = 0.02 nd
Shot 5: f/16 = 0.12 d = 0.03 nd
Shot 6: f/11 2/3 = 0.14 d = 0.05 nd
Shot 7: f/11 1/3 = 0.16 d = 0.07 nd
Shot 8: f/11 = 0.09 d = 0 nd
Shot 9: f/22 1/3 = 0.09 d = 0 nd
Shot 10: f/22 2/3 = 0.09 d = 0 nd
Shot 11: f/32 = 0.09 d = 0 nd
Shot 12: f/45 = 0.09 d = 0 nd

The results I had shot before (shots 1-5 and 9-11) are pretty comparable. Shot 12 was to be expected and so I didn't shoot in thirds of an aperture stop after shot 11 (again, I wanted to be damn sure). As someone pointed out, though, the fun happens in shots 6 and 7, where my density starts going up and gets much closer to 0.1. The head scratcher is shot 8. Why, all of a sudden, did the density go down here? From (shots) 3 to 7, the density was climbing, then, on 8, it dropped. There was nothing different done while shooting this. They were shot in the number I described above, so I expected the number to be higher and therefore, much closer to 0.1. I really don't know what happened there. Maybe shot 7 shows this particular film at its highest density? I don't know. In any case, shot 7 brings me to an ASA of 32. Rounding this number to the closest lower ASA number (if I understood Ansel Adams correctly), this means that with this particular film-lens-film combo, I have to shoot as though it were a 25 ASA film. Is my assumption correct?

What do you guys think?

Thanks.

Hi Mario,

Exactly what it means. You may proceed under the assumption that your speed is 25 or 32, for 7 minutes in D-76 stock for Arista EDU 100.

You can see a trend supporting that conclusion. Whether you want to give the extra 1/3 stop based on trend and call it 25 (ignore 8 but believe it would have been 0.1 nd if correctly tested). Or if you want to take 32 as the speed (7 is the closest you had to correct, but since it is a real test result, you know what you would get). Is up to you.

Bill Burk
20-Apr-2013, 08:43
Maybe you can call it 50 or 64. I am re-thinking how the finding of the 0.1 net density should relate to your chosen EI speed. I may soon recommend making adjustment when you perform a test without flare.

I believe your camera test was without flare.

The clearest explanation of the reason you can choose a higher speed than your tests results suggest comes from Ansel Adams himself...

Francesco Fragomeni shared a video of Ansel Adams, narrated by Beaumont Newhall.

Listen at 8 minutes, 11 seconds in... "Shadow densities exactly on the right Zone. A little camera flare helped the shadow as expected."

Early-ansel-adams-footage (http://francescofragomeni.tumblr.com/post/43868348233/early-ansel-adams-footage-showing-the-photographer)

Chuck P.
25-Apr-2013, 05:09
Maybe you can call it 50 or 64. I am re-thinking how the finding of the 0.1 net density should relate to your chosen EI speed. I may soon recommend making adjustment when you perform a test without flare.

The adjustment can also be made on a per exposure basis, using an educated guess as to how much flare may be possible given the subject, I don't like the idea of considering flare to be some mathematical statistical average always to be considered as some constant----I've got too many negatives without any consideration for flare at all that are inarguable in terms of the quality of the exposure and processing and resulting densities-----but! that's not at all to mean that they are equally as good in terms of "art". This is what I do anyway while keeping the EI constant as determined by my own flare-free film test (as found in Schaefer). I'll make a small adjustment with the aperture or shutter (depending) just like you have suggested with assigning a higher EI to adjust for flare, the effect is the same either way, I don't fiddle with the speed rating while in the field. We can't control the subject flare, but we can combat it's effect on the toe of the curve, IMO.

This is, IMO, what AA did by making such a low shadow placement (Zone I) in the video you referenced. That was a high contrast lighting situation (bright sun with distinct, strong shadows) with the shadows placed on Zone I, with the full intention of flare helping to bring the shadow densities back up to a preferred amount. Did he control flare from the scene, no----but he did control it's impact on the toe of the film curve by intentionally providing less exposure to the shadows than what may normally have been given if flare was not a concern for that exposure. Anyway, that's my take on it.