Calibrating 4x5; gray card Zones don't match still life Zones

[Richie]

I have been getting a lot of inconsistent, unpredictable densities as I have been trying to calibrate my 4x5 camera. I will describe a problem I saw yesterday with idea that somebody might have a hint as to what might be going on. I am a newbie. I am calibrating camera and film and development time and print for an intro to zone class. The teachers have not been able to figure out what is going with me and my camera.

I am calibrating a 4x5 camera (Linhof Master Technika with Fujinon 5.6/150mm lens) , using HP5+400, HC-110 developer, N+1 (development time for this batch was 11'15"), ISO 125. I shot 6 frames and developed them together using tanks and hangers. I shot a gray card with lens cap on for Zone 0, then exposed for Zone I, Zone II, Zone III, Zone VI (1/15, f/64; 1/15, f/45; 1/15, f/32; 1/15, f/11 respectively.) My densities were an absolute 0.09, and net densities of 0.37, 0.63, 0.81, 0.135, the target net densities are 0.10, 0.30, 0.45, 1.05.

The fifth shot was an indoor still life. I placed my shadow detail in Zone III (125 ISO, 1/15, f/14), my highlight detail (Zone VI) was a measured 3 stops greater than my shadow detail. Zone III area on the negative measured 0.24 and the highlight detail measured 0.94. On close inspection of the negative, it looks like I have good detail where I placed Zone III even though I only have 0.24 net density, not the target 0.45.

I don't think the lens magnification factor is an issue. I shot with the lens about two feet the gray card so that I could only have only the gray card on the negative. My 150mm lens was about 150mm from the film plane. Maybe this is called the bellows extension.

In summary, the problem is the gray card densities are 2 or 3 stops higher than I expect them to be AND they are 2 or 3 stops higher than my still light, even though all negatives used the same studio halogen lights and were developed together in the same batch. Does anyone have an idea what might be going on?

[Ken Lee]

You may find this article helpful: http://www.kennethleegallery.com/html/tech/testing.php

[Neal Chaves]

I have explained my HP5+ exposure and development testing procedure below. You don't specify what your dilution of HC110 was or what the temp was. I can tell you that if I rated HP5+ at 125 and then developed for 11:15 in HC110B @68*, my negative would be so dense as to be unprintable.



Years ago I learned the method to find the correct developing time and EI for any film. I source was an article by William Mortensen. Mortensen wrote some excellent books and articles about basic sensitometry. The last time I did this test was when I abandoned Tri-X and switched to HP5+ due to cost about five years ago. I proceed as follows.

I set up my trays with my favorite developer HC110B (1:31). I pull out a sheet from the package in the dark. and then when the package is sealed again I turn on the room lights. This part of the test is done under the lights. I cut the sheet into five strips and mark them 1-5 by punching holes with a paper punch. Lets say the recommended time is 5:00. I want to see 3:00, 4:00, 5:00, 6:00 and 7:00, so I throw all the strips into the developer and agitate as usual until 3:00 when I move the No.1 strip over to the stop bath. Then I pull No.2 at 4:00, No.3 at 5:00, etc. I fix, wash and dry the strips as usual. What we are looking for is the best usable film DMax value. Obviously the film has been fully exposed! When strips dry lay down a page of news print on a table in good light. Find the strip through which the news print is barely visible. That's your developing time. Now to find the film speed.

Go outside in unchanging light conditions and expose five sheets and expose one at the manufacturers rating and then the other four at one half a stop and one stop less and one half a stop and one stop more. In the dark, develop them all together for your newly derived time. Contact print them together exposing and developing the paper for maximum usable paper DMax value. Pick out the best-looking contact print and you have your film speed.

Because my 7:00 negative looked the best on the first test, I did the test again with 7:00 as the central developing time and found that 8:00 was indeed too dense. This HP5+ time was the same as the as the developing time I had been using for Tri-X and film speed was also the same, EI400.

Many of the last generation of B&W gurus favored a development time of 5:00 for Tri-X and suggested an EI of 64-100. You can do the above test backwards, developing for 5:00 minutes and finding the film speed. I like 100. The difference between negatives exposed at 100 and developed for 5:00 is quite subtle. Both could be considered "normal" or N negatives. The 100 negative has slightly greater shadow and highlight detail that only a careful, knowledgeable viewer could detect. This slight improvement might not be worthwhile trading for two stops in the field. I do routinely rate HP5+ at 100 under powerful strobe light in the studio and it produces beautiful skin tones.

From here, if you are still with me, you can derive expansion and contraction schemes for both the 100 and 400 "normal negs". I do this by changing dilution rather than time. Make sure you have at least 1 oz. of the concentrated sauce for each 8X10 sheet or equivalent. For contraction I found that 3/4 oz. concentrate to 31 1/4 ozs. H20 yields an N-1 neg at a one stop loss in film speed and 1/2 oz. concentrate to 31 1/2 ozs. H20 yields an N-2 neg at a two stop loss in film speed. For expansions, 1 1/4 oz. of concentrate to 30 3/4 ozs. H20 yields an N+1 neg at a one stop gain in speed and 1 1/2 ozs. concentrate to 30 1/2 ozs. H20 produces an N+2 negative with a two stop gain in speed.

If you look at the chart of Tri-X film speed in Phil Davis' BTZS book you can easily pick out the film speed in HC110B 5:00 as EI 64.

Don't apply reciprosity exposure and development corrections for long exposures (1/2 sec. +) based on published data. Test for yourself and you may be surprised. I wasted a lot of time and effort producing long exposure negatives that were thick and flat. When I finally tested, I found no compensation was required for TXP out to one minute.

If you are curious about the density of very low values, don't expose with the lens cap on. All lenses, even the latest multicoated ones exhibit some flare which will affect low values. Instead, make a target box at least a foot deep and cover the back wall with black velvet. Then expose normally for the surrounding scene and later measure the density of the black target area.

[Richie]

You may find this article helpful: http://www.kennethleegallery.com/html/tech/testing.php

Thanks Ken. I did find your article helpful. If I can't find out why I am getting different gray card densities than scene densities on this thread, I will abandon shooting the gray card and try to calibrate using scenes. I found your recommendations about how to shoot scenes for calibrating very helpful. I also plan on scanning as well as darkroom printing of my negatives so I am eager to study your recommendations for scanning film.

[Richie]

Neal, my dilution was E (1:47) and my temperature was 68 degrees Fahrenheit.

[Neal Chaves]

HC110 is so economical that I see no need to dilute it more than 1:31 (B) except for the N-1 and N-2 above to give a longer working time. One must use at least 1 ounce of the concentrate per 80 sq. inches of film to ensure complete one-shot development with a 100% safety factor. When you use very dilute mixtures, you need a lot of water in large trays. You can't do it in small tanks. I got away from tanks and hangers for development years ago and learned to shuffle the 4X5s and 8X10s in trays. Now when I do 8X10s I usually develop only one sheet at a time face up in an 8X10 tray. Now I am using Ilford Ilfotech HC at the exact same times and dilutions as HC110 and notice no difference. Most dealers will not ship HC110 and the Iford is less expensive as well.

[faberryman]

I'm curious; why are you using HP5 Plus at ISO 125? That would be almost two stops overexposed. That may explain why you find that your "densities are 2 or 3 stops higher than I expect them to be".

[ic-racer]

I don't know of any useful film/paper testing method whereby one matches scene density values to print values 1 to 1 outside of copy work.

[Andrew O'Neill]

EI 125 is pretty low for that film and developer combo. You have done an EI test, correct? Almost everyday conventional and staining developer that I have used requires an EI anywhere from 200 to 250. You need to lock that in first before you proceed.

[Bill Burk]

I agree with faberryman and Andrew O'Neill,

You are getting results that look like they came from a 400 speed film. You did a series of Zone System exposures at 125, but the film is a 400 speed film. It's responding like a 400 speed film to the increased exposure that you gave it, so you are getting higher densities than the target. Your densities look good for a 400 speed film.

When you took your photograph of the still life, it seems you gave it an exposure appropriate for a 400 speed film.

[Leigh]

Getting accurate spot readings of a real subject is quite a skill, requiring years of practice to achieve with consistency.

The reflectance characteristics of real materials and surfaces can vary all over the map.

You need to build a still-life subject with fixed lighting, not flash.

Take an incident reading with the dome facing the camera lens.
Then work with a spot meter until you get exactly the same reading from an 18% gray card.

That's the way the system is calibrated by definition.
If your results vary, your technique is wrong.

- Leigh

[John Layton]

Keep in mind that all gray cards are not created equal. I was teaching a class on the Zone System many years back...during which I supplied each student with his/her own gray card, then shared out my Zone-VI modified Pentax spot meter - and results were inconsistent. The problem? The gray cards were basically "el-cheapos," manufactured using a rather shiny card stock - thus exhibiting a high degree of specularity, even in relatively flat light. I then purchased a much better gray card - made of a plastic material and finished with a good matte surface. Ideally, a gray card would exhibit no specularity at all. This is why I often trust an incident reading over a gray card reading. Not saying to ignore specularity...just that the specularity exhibited by a cheap gray card would likely not relate to that of a given subject.

[djdister]

From what I can tell, you overexposed and overdeveloped your film. For a film test, why not start using the rated film ISO (400) and Normal development?

Secondly, why are you surprised that a gray card exposure was different from an exposure based on a real life object? It is quite possible that your zone placement of the still life object was an artificial or inappropriate setting (i.e. such as deciding to place a deep shadow tone higher up the zone scale than it should be naturally). For your still life, if the lighting and everything else was the same, you could/should have used the gray card indicated exposure for the still life. Or at least, compared the zone settings you were getting from the still life with your gray card zone settings to see how the placement of tones would compare.

Lastly, your film test with the gray card should really just be to determine your effective film speed and optimum development combination, and that's all.

[Bill Burk]

Here is a graph

I show what your teacher had you aiming for in dotted line and you can see the exposure and aim are for ASA 125 normal (I think it is pretty cool your teacher had you aim at ASA target. Anyway you can call that N+1).

Your line is the solid line above that.

Since you used 400 speed film, your film is more sensitive to light and you got higher densities for each test point. You can see the two graphed lines parallel each other.

That means you got the development time right.

Then when you did your still-life, you used appropriate exposure, and got appropriate results for 400 speed film.

157295

[Leigh]

If your teacher told you to expose an ASA 400 film at ASA 125 on a normal subject, he screwed up.

Modification of film speed is used to accommodate extreme variations in the subject or lighting conditions.

We usually consider the "detail" range of a subject to be 7 zones, being II through VIII on the negative.

So the first step is to assess the detailed areas of the subject and determine its "natural" range.

If it differs significantly from the expected 7 zones, you modify exposure and/or development to compensate.
Exposure changes affect the shadow detail and highlights. Development changes affect the highlights.

- Leigh

[Richie]

thank you all so much. I don't understand most of the feedback. Perhaps because I am a newbie.
I chose an EI of 125 because previous tests of a gray card Zone I where I found appropriate densities with ISO 125 and one of my teachers after looking at many of my tests of gray card said he thought it was 125. However, yesterday after getting the feedback that ISO 125 with HP5+400 was unlikely. I did more tests of varying ISOs. I have been getting more consistent densities using a still life scene with flood lights than with the gray card so I have switched to using still-life scenes to calibrate. Here are the results of yesterday's test of N+1. All densities except Zone 0 are net densities. DT HC-110, 1:47, 11’30”, 68 degrees Fahrenheit. I am using a Saunders Enlarger. My target densities for Zone III and Zone VI (pushed to VII) are 0.45 and 1.20

ISO, Zone, Camera Settings, Density
NA 0 NA 0.10
250 III, VI 1/15, f/20 0.32, 0.97
200 III, VI 1/15, f/18 0.37, 0.97
160 III, VI 1/15, f/16 0.42, 1.04
125 III, VI 1/15, f/14 0.49, 1.09
100 III, VI 1/15, f/13 0.57, 1.10

As you can see, at least from this test, ISO 125 doesn't seem so far off, although 160 is a little closer to the target. (I know Bruce Barnbaum thinks measuring densities is useless, but from what he says about shadow detail a little farther out of the toe towards Zone IV might be even better.) My plan today, unless one of you says something that might change my mind, is to stick with an EI of 125 and increase my development time by 30" to 12' in order to pull Zone VI up to 1.20.

I just re-read this. The way I wrote it may lead to a misunderstanding. These densities are from negatives, not prints. I mentioned the Saunders Enlarger in order to explain why my target Zone VI target density was 1.20.

[Ted R]

I have been making prints using 35mm, 120 and large format film for thirty years and never felt the need for a density reading. Instead I follow the film maker's instructions for film speed and development. I make sure I follow the instructions carefully. I make prints using variable contrast paper. I get high quality results. I am able to make a print of a gray scale that matches the original when placed next to it.

While you are learning I urge you to step back and adjust your choices of materials and methods to be exactly "by the book". Once you have established the normal performance of your chosen materials and processes there will be opportunity for experimentation when the necessity arises, however it seems to be inviting trouble to begin by deviating from normal exposure and development of film material. Relying upon density readings seems to add fuel to the fire.

Why not make a nominal exposure, give nominal development and print the result on a selection of paper contrasts and inspect the results. Calibrating a camera lens film and developer is a fine tuning process for the advanced user who has established competence with normal materials.

[Richie]

Thanks Ted for your thoughtful and kind response. I appreciate you taking the time to write, particularly from your thirty years of experience. My response may not be adequate but it is simple: I am taking a Photography Class, Introduction to Zone. I am completing the assignments for the course. In this moment, I am trusting the wisdom of my teachers. I posted here to see if someone could help me understand the results I have been getting. Something that my teachers and I haven't been able to figure out.

[Ken Lee]

I posted here to see if someone could help me understand the results I have been getting. Something that my teachers and I haven't been able to figure out.

It may not be too much of a mystery. Given that HP5+ is basically ISO 250 for N development *, if you're getting 125 you are off by 1 f/stop. If your lens is focused closer than infinity, that can cost you a fraction of an f/stop. If your shutter speed is off - or your thermometer - or your water - or your agitation...etc. those can cost a few more fractions. Those fractions can easily add up to 1 f/stop.

* You might find it helpful to search this forum for discussions about film speed and why manufacturers provide the ISO numbers as they do.

One of the principal benefits of working with the Zone system is to get you to see in B&W. It's a bit like learning scales and intervals in western music, or ragas in Indian music. In the end it's inspiration which matters, but it manifests through a command of the grammar.

[Jim Noel]

thank you all so much. I don't understand most of the feedback. Perhaps because I am a newbie.
I chose an EI of 125 because previous tests of a gray card Zone I where I found appropriate densities with ISO 125 and one of my teachers after looking at many of my tests of gray card said he thought it was 125. However, yesterday after getting the feedback that ISO 125 with HP5+400 was unlikely. I did more tests of varying ISOs. I have been getting more consistent densities using a still life scene with flood lights than with the gray card so I have switched to using still-life scenes to calibrate. Here are the results of yesterday's test of N+1. All densities except Zone 0 are net densities. DT HC-110, 1:47, 11’30”, 68 degrees Fahrenheit. I am using a Saunders Enlarger. My target densities for Zone III and Zone VI (pushed to VII) are 0.45 and 1.20

ISO, Zone, Camera Settings, Density
NA 0 NA 0.10
250 III, VI 1/15, f/20 0.32, 0.97
200 III, VI 1/15, f/18 0.37, 0.97
160 III, VI 1/15, f/16 0.42, 1.04
125 III, VI 1/15, f/14 0.49, 1.09
100 III, VI 1/15, f/13 0.57, 1.10

As you can see, at least from this test, ISO 125 doesn't seem so far off, although 160 is a little closer to the target. (I know Bruce Barnbaum thinks measuring densities is useless, but from what he says about shadow detail a little farther out of the toe towards Zone IV might be even better.) My plan today, unless one of you says something that might change my mind, is to stick with an EI of 125 and increase my development time by 30" to 12' in order to pull Zone VI up to 1.20.

I just re-read this. The way I wrote it may lead to a misunderstanding. These densities are from negatives, not prints. I mentioned the Saunders Enlarger in order to explain why my target Zone VI target density was 1.20.

If you are following Barnbaum's boook, throw it away. His methods work for him but not many others. Step 1 - determine your EI Step 2 determine your normal development time Step 3 use this info on rea subjects, still life or other, and make the minor adjustment needed.

[Ted R]

Thanks Ted for your thoughtful and kind response. I appreciate you taking the time to write, particularly from your thirty years of experience. My response may not be adequate but it is simple: I am taking a Photography Class, Introduction to Zone. I am completing the assignments for the course. In this moment, I am trusting the wisdom of my teachers. I posted here to see if someone could help me understand the results I have been getting. Something that my teachers and I haven't been able to figure out.

I may be missing something but the Kodak data sheet for HC110 gives times for dilutions A and B but not for other dilutions. What is your development time based on?

How about using dilution A or B and using the recommended development time from the data sheet? Use the film at 400. Do everything exactly by the book to obtain a reference situation. From this you may evaluate the results and arrive at an individual calibration for your system, if needed. We have to walk before we can run, calibrating zone system is running.

Photography is a creative skill, densitometry is the measurement and control of image quality for the image processing industry where they handle other people's images and don't make images, I urge you to throw away the density meter.

[faberryman]

How are you determining what area of the negative is Zone I to measure with your densitometer if you are shooting scenes instead of an evenly lit card?

[Ted R]

PS

Ilford film data sheet for HP5+ gives development times for Kodak HC110 in dilutions A and B for 400, 800 and 1600 speeds but not for slower speeds which you used. What are you basing your film speed+developer combination on?

If you want to shoot HP5+ at 125 there is no recommended developer.

When we are trying to calibrate a system we have to start with the original specifications and test the results they give, that is the starting point, the reference. If on the other hand we start by experimenting with uncharted variables we should expect the unexpected.

Perhaps it would be a good idea to reshoot using 400 and dilution A or B for the recommended time and evaluating the results.

[Richie]

I may be missing something but the Kodak data sheet for HC110 gives times for dilutions A and B but not for other dilutions. What is your development time based on?

How about using dilution A or B and using the recommended development time from the data sheet? Use the film at 400. Do everything exactly by the book to obtain a reference situation. From this you may evaluate the results and arrive at an individual calibration for your system, if needed. We have to walk before we can run, calibrating zone system is running.

Photography is a creative skill, densitometry is the measurement and control of image quality for the image processing industry where they handle other people's images and don't make images, I urge you to throw away the density meter.

Hi Ted, thanks for trying to help me. The website Digital Truth gives development times for HC110E, 1:47, matched with HP5+.

[Ted R]

The chart seems to show 7.5 minutes for 400. Using 11.5 minutes might be appropriate if you had shot at higher speed (>400) however you shot at 125 and developed for 11.5, something is wrong here, over exposure and over development.

Kodak publish the recommended data for HC110, they are the source of authoritative information on dilution and time. When we are trying to calibrate something it is a good idea to eliminate uncertainty by only using authoritative data, use someone else's data at your own peril, it is an uncontrolled variable. Only use dilution A or B, for which Kodak gives data that can be trusted.

Ilford gives no recommendation for HP5+ at speed 125, why are you shooting at 125? You are introducing unquantified variables into a calibration procedure. Decide what you want to do, either experiment or calibrate? Don't try do both at the same time.

When we calibrate something only one variable is allowed. In your system there are four, the lens glass light transmission, camera flare, the shutter times and the aperture calibration. To have any chance of accuracy the film speed and processing need to be the nominal values, that is 400 and normal development.

[Leigh]

The website Digital Truth gives development times for HC110E, 1:47, matched with HP5+.
Based on what?

If we believe everything we find on the web, the world will be in very dire straits indeed.

For testing any photographic process, start with the recommendations from the manufacturers ONLY.
If your results don't match, the problem is at your end.

Fine-tune your process until you get results that match the documented results.

Then you can play with times, dilutions, etc to gain more insight into how the materials and chemicals behave.
But only then.

Understand that the problems you're reporting go against 100+ years of industry experience.
Are we to believe you, or several million previous reports and results?

BTW... Regarding your test exposures:
How did you set the intermediate apertures? Only f/16 is calibrated on your shutter.

250 III, VI 1/15, f/20 0.32, 0.97
200 III, VI 1/15, f/18 0.37, 0.97
160 III, VI 1/15, f/16 0.42, 1.04
125 III, VI 1/15, f/14 0.49, 1.09
100 III, VI 1/15, f/13 0.57, 1.10

- Leigh

[Ted R]

When I started in photography I learned a lot from books on a variety of topics including exposure.

I can recommend this one: Exposure Manual by Dunn and Wakefield, it is written for the photographer not the scientist and is profusely illustrated, it can be found among other places at amazon at a very low price: https://www.amazon.com/Exposure-Manual-Jack-Frederick-Dunn/dp/085242762X/ref=sr_1_2?s=books&ie=UTF8&qid=1478988154&sr=1-2&keywords=dunn+and+wakefield

Books are helpful in that to get a book published (a hardcopy book) the publisher choses an author who is respected for being knowledgeable and readable. Today the internet permits everyone to publish online but the quality of the author's knowledge and experience is invisible, unfortunately, so the content comes with some uncertainty.

[neil poulsen]

. . . When we are trying to calibrate a system we have to start with the original specifications and test the results they give, that is the starting point, the reference. If on the other hand we start by experimenting with uncharted variables we should expect the unexpected. . . .

This is for good reason. We begin by testing ASA, which is based on Zone 1 exposures. Zone 1 film densities vary relatively little with changing development times. So, one can begin with Mfg. recommended times and still have a successful calibration, even though the final "N" development time might be different.

[Andrew O'Neill]

Your density readings at EI 250 for zones III and VI are close to my own personal readings. Stick with EI 250 for "normal" contrast scenes. N+1 I use EI 320, N-1 EI 200. When you start printing your negatives you may find that an adjustment in EI and/or development times is in order. Just look at your results, and listen to what your images are saying to you. Keep good notes.

[Bill Burk]

In your first post you explained:

... "using HP5+400, HC-110 developer, N+1 (development time for this batch was 11'15"), ISO 125. I shot 6 frames and developed them together using tanks and hangers."...

In that test you achieved a contrast of 0.6

In my opinion, based on interpretation of the graphs, you got the development time right, because your graphed curve is parallel to the curve your teacher gave you to match, which is a curve that is similar to the standard ASA aims.

You do not need to develop any longer unless you want N+2

[Leigh]

Stick with EI 250 for "normal" contrast scenes. ...N-1 EI 200.
A half-stop (25% speed) change in EI yields a full stop change in negative density ? ? ?

How do you consistently achieve a 25% exposure change when the standard tolerance for shutter speed is +/- 30% ? ? ?

These are old shutters, not new computerized exposure controls.

- Leigh

[Bill Burk]

Originally Posted by Andrew O'Neill: "Stick with EI 250 for "normal" contrast scenes. ...N-1 EI 200."

Leigh asked: A half-stop (25% speed) change in EI yields a full stop change in negative density ? ? ?"

I believe Andrew O'Neill is recommending a sliding EI scale. He recommends different EI at different N +/- numbers to try to hold 0.10 density at the speed point for Zone I. The 0.1 speed point normally fluctuates with development time changes.

The "full stop of negative density change" when you specify N+/- whole numbers... occurs at the higher Zones like Zone IX moving down to Zone VIII with N-1...

This kind of film speed adjustment is a common Zone System (or Beyond the Zone System) practice.

(I personally look to "the Delta-X criterion" to justify using one EI for all my development times).

{Richie, sorry I think I stepped outside the scope of "beginning Zone"... I'll try to keep future comments in this thread more relevant to your questions.}

[Leigh]

The 0.1 speed point normally fluctuates with development time changes.
Hi Bill,

Development time has minimal impact on shadow densities (thin areas) of a negative.
It has a large impact on highlight densities (Dmax).

Perhaps the advocates of BTZS have invented new photographic chemistry.

- Leigh

[neil poulsen]

Hi Bill,

Development time has minimal impact on shadow densities (thin areas) of a negative.
It has a large impact on highlight densities (Dmax).

Perhaps the advocates of BTZS have invented new photographic chemistry.

- Leigh

Exactly!

This is what makes the Zone System as practiced by A.A. (et.al.) click. One can expose for the shadows, and then later, choose the developing time for the highlights, without compromising the original decision made for the shadows.

Put another way, regardless of what development time is selected (N-2, N-1, etc.), the shadow areas will stay "pretty much" unaffected. That is, they'll come out "pretty much" as anticipated, when the photographer originally decided on the exposure. (At the time that the photograph was taken.)

There really is an elegance to how this all works out.

[Leigh]

OK.

That's how I've always used it.

"Expose for the shadows, develop for the highlights." (I didn't originate that.)

But that seems to contradict what Bill said:

I believe Andrew O'Neill is recommending a sliding EI scale. He recommends different EI at different N +/- numbers to try to hold 0.10 density at the speed point for Zone I. The 0.1 speed point normally fluctuates with development time changes.

- Leigh

[Doremus Scudder]

Exactly!

This is what makes the Zone System as practiced by A.A. (et.al.) click. One can expose for the shadows, and then later, choose the developing time for the highlights, without compromising the original decision made for the shadows.

Put another way, regardless of what development time is selected (N-2, N-1, etc.), the shadow areas will stay "pretty much" unaffected. That is, they'll come out "pretty much" as anticipated, when the photographer originally decided on the exposure. (At the time that the photograph was taken.)

There really is an elegance to how this all works out.

Well... to a certain extent this works, but as Bill points out (correctly), the Zone System speed point moves around a bit with different development. Film is a bit faster with expansions (N+X) and slower with contractions N-X). The slight overexposure with expansions won't affect printability of a neg much, but you can lose shadows with contractions if you're not careful.

I find I need at least 2/3-stop more exposure when solely using reduced development time for N-2; more compensation for greater contractions. So, if you're planning a larger contraction, be sure to support your shadows by increasing exposure. I have simply memorized exposure compensations for my different development schemes.

Best,

Doremus

[faberryman]

How are you guys getting 1/3 and 2/3 stop exposure changes? On my Schneider lenses, the shutter speeds are at fixed 1 stop intervals, and while the apertures are continuously variable, only full stops are marked. If you get an exposure reading of 1/8 at f18, do you move the aperture lever as smidge past f16? How confident are you about the accuracy of your smidges? Are the shutters on all of you lenses calibrated so you know if they are a 1/3 step over or under (or worse)?

[neil poulsen]

Well... to a certain extent this works . . .

I appreciate the input on this, which I will bear in mind.

As to my own practice, I rarely use N-2, mostly N-1, N, N+1, and once and a while greater expansions. For shadows, I may consider what I can expect for a Zone III area in a scene, but I like to expose for Zone II. Less change in speed that way. (Lower on the toe.) Not entirely sure about the wisdom of this; it's just what I do. :)

As for testing B&W film speed using the 0.1 fb+f methodology, perhaps one can think of this analogously as lowering color film speed somewhat from that recommended by the manufacturer, so as to make sure that there's sufficient detail in the shadows. This is a common practice in color negative photography.

I've always thought that "0.1" for B&W film was selected as the smallest value that minimizes the exposure needed to, none the less, provide sufficient detail in the shadows. In this regard, shooting B&W film at the mfg. recommended film speed just doesn't cut it. At least, not for me.

[Bill Burk]

{Richie, sorry about adding deeper concepts than you need in your beginners' thread.}

First off, I agree development time has minimal impact on the exposure needed for usable shadow densities of a negative.

The arcane point I am making is that it is a mistake to take your speeds from the 0.1 speed point "all the time". Because the 0.1 speed point moves around a lot. Just look at the little diamonds I drew on the toes of their curves where they cross 0.1... then look up at the associated film speed that you would find... if you always take the 0.1 speed point.

157502

http://beefalobill.com/images/tmxfamily.jpg

[Drew Bedo]

Not a strict Zone guy myself so please accept my remarks with the tolerance you would give to a 5 year old ("yes dear . . .that's nice".)

Bracketing? You are shooting bunch test films, why not shoot several sheets of the scene in thirds of a stop, or whatever interfal you think best? Not only will you get he technical info you are looking for, but some images may be worth printing.

Make sequential exposures on one sheet of film while drawing the slide 1/3 or 1/2 way. ADjust the shutter speed and aperature to get the exposure you want. The development will be identical for each increment of exposure.

A more elegant solution for making two exposures on one piece of film would be a sliding back.

Cheers

[Doremus Scudder]

How are you guys getting 1/3 and 2/3 stop exposure changes? On my Schneider lenses, the shutter speeds are at fixed 1 stop intervals, and while the apertures are continuously variable, only full stops are marked. If you get an exposure reading of 1/8 at f18, do you move the aperture lever as smidge past f16? How confident are you about the accuracy of your smidges? Are the shutters on all of you lenses calibrated so you know if they are a 1/3 step over or under (or worse)?

Simple: If I need 2/3-stop more exposure, I'll set the shutter speed to the next lower setting (e.g., from 1/15 to 1/8 second) and then adjust the aperture smaller 1/3-stop from it's original position. Sure, there are no intermediate apertures marked on many shutters, but that's not an insurmountable problem; just eyeball the proper position. If you miss, it's likely to be only by a much smaller fraction of a stop, say 1/6 stop or less, which will have virtually no impact on a B&W negative.

By the way, I use third-stops for all my testing, therefore the adjustments in the same increments. I test my shutters regularly and mark the actual speeds to the nearest third-stop. Estimating third-stop increments by eye with the aperture setting is fairly accurate too. That said, I'm well aware that the margin of error in exposure likely sometimes exceeds my attempts at third-stop accuracy. Nevertheless, trying to be as accurate as practical helps keep the margin of error as small as possible. I use third-stop increments because film speed and most curve charts, etc. use third-stop increments.

If you don't want to go to the trouble of estimating between-stops, just use what's convenient for you. As long as you err on the side of overexposure, a third, half or even a full stop overexposure won't hurt anything. I wouldn't hesitate to use a full stop extra instead of 2/3-stop, since that's only 1/3-stop more, and will have no practical effect on the printability of the negative. However, I'm usually trying to squeeze out a bit more DoF and even a 1/3-stop smaller aperture makes me feel better.

Best,

Doremus

[Doremus Scudder]

I appreciate the input on this, which I will bear in mind.

As to my own practice, I rarely use N-2, mostly N-1, N, N+1, and once and a while greater expansions. For shadows, I may consider what I can expect for a Zone III area in a scene, but I like to expose for Zone II. Less change in speed that way. (Lower on the toe.) Not entirely sure about the wisdom of this; it's just what I do. :)

As for testing B&W film speed using the 0.1 fb+f methodology, perhaps one can think of this analogously as lowering color film speed somewhat from that recommended by the manufacturer, so as to make sure that there's sufficient detail in the shadows. This is a common practice in color negative photography.

I've always thought that "0.1" for B&W film was selected as the smallest value that minimizes the exposure needed to, none the less, provide sufficient detail in the shadows. In this regard, shooting B&W film at the mfg. recommended film speed just doesn't cut it. At least, not for me.

Neil,

The Zone System is primarily a system for visualizing tones in the final print and then making sure the negative contains the info one needs (exposure) and is developed so that it is the easiest possible to print (development). Placing a shadow on Zone III, or II or I, or even IV or V is an interpretive decision. I like shaded snow on Zone V a lot of times. Dark shaded doorways often get Zone II placement from me. If I need something really black, I'll place it in Zone I or even 0, depending on where everything else falls. The main thing is to know that whatever placement you use will get you the information in the negative in the right place in relation to the other luminances in the scene. Choosing development is similar; we want the easiest neg to print with the tonal separation on the neg that we desire, even if it requires significant printing manipulations (note, often this latter makes for what many ZS users would call overdevelopment).

When I make exposure adjustments for expansions and contractions, they are based less on the ZS speed point and more on keeping shadow information and separation. Additionally, I often indicate N- developments in conjunction with an expected printing with a grade 3 or 4 contrast grade; this latter to maximize tonal separation in adjacent tones (micro-contrast if you will). These negs, then, are developed even less than a contraction neg designed for grade 2 or 2.5 and need more exposure support for the shadow separation.

BTW, the 0.1 above fb-fog for B&W ZS use is the Zone I speed point, and should print close to max. black. Zone III density is quite a bit higher than this.

Best,

Doremus