View Full Version : Exposing a gray scale for Zone System calibration
Hello, all!
I just got access to a darkroom so I am going to start doing my first round of zone system calibrations. As one of the final steps, Brian Lav suggests making a gray scale using your process for future reference. Rather than blow through 10 sheets of film would it be safe to do the following:
Set up a gray card and meter for a zone 1 exposure. Pull my dark slide out 1/10th of the way and expose. Pull it out 1/10th more of the way and expose again. Continue until you have (in theory) a 10-step grayscale. Does that work how I think it will? Because the first step got exposed to a zone 1 exposure ten times, does that make it Zone X?
Thanks, y'all!
Christopher Barrett
9-Jul-2017, 19:18
Not really. Your first increment will have a one stop difference but all of the subsequent steps will have smaller and smaller separations. With a base exposure of 1 second your strip would look like this...
1s / 2s / 3s / 4s / 5s / 6s / 7s / 8s / 9s / 10s
But to have 1 stop increments you would want something more like...
1s / 2s / 4s / 8s / 16s / 32s / 64s / 128s / 256s / 512s Now this isn't precisely correct because exposures shift logarithmically, but it should be fairly close. You can see how this changes things pretty dramatically. Also, just to get at these exposures requires even more math to figure out the cumulative final exposure times per step. Oh my head...
I'm assuming your greyscale strip should have 1 stop increments, yeah? Someone please correct me, if my logic is faulty.
-CB
I believe the saying is "duh!". Thanks for pointing that out. I guess 10 sheets of film is cheaper than buying a broadcast chip chart of a gray scale. I'm glad someone stopped me before I was standing with a print in my hands shouting "do'oh!"
neil poulsen
9-Jul-2017, 22:00
How people do calibrations vary. (O course.) So, I can offer come comments based on my own approach.
Let's assume that you've completed your calibrations and know the following:
1] Tested film speed. (Usually about half the manufacturer stated speed.)
2] Determine paper maximum black for the paper of choice. (In my case, Ilford Warmtone fiber.) That is, determine the minimum exposure that maximizes black at whatever enlarger height, enlarger lens aperture setting, and light intensity, when exposed through a film-base plus fog negative. (I develop a negative that hasn't been exposed to light at mfg. recommended development time and temperature.) For maximum black, I determine that minimum exposure time that maximizes paper black through that negative. (But no greater.)
3] Normal "N" development time.
Knowing these, to get my Zone System gray scale, I would expose negatives respectively to light at Zones I, II, III, IV, V, VI, VII, VIII, and IX, develop each at Normal development, and print each of these negatives on nine sheets of about 4x5" paper at maximum black. This give one an idea of how each zone will print in the final print, when the negative is exposed normally
To construct the actual scale, I would trim each paper to about 1"x1.5" and mount these rectangles in order (Zone I through Zone IX) side by side on a strip of museum rag, four-ply mounting board with dimensions 9"x1.5".
As a caveat, I hear people say t hat a Zone V exposure should be about 68% gray. (Or, whatever.) It doesn't work out that way for me, and it doesn't really matter if it doesn't.
I agree -- you can't expose film in a vacuum. You need to determine what comes AFTER the film exposure FIRST.
167034
Check out: http://www.subclub.org/darkroom/henry1.htm
Doremus Scudder
10-Jul-2017, 11:52
Early on, I made Zone Rulers (Minor White's moniker for what you're doing) for all my different development schemes. It helped a lot in learning visualization of tones, especially for the expansions and contractions where Zone V is usually not anywhere close to 18% grey. Each development scheme has its own "scale" of greys and different intervals between the patches.
I expose two sheets of film divided into fifths or sixths (depending on how many stripes I need). Here's my method for nine stripes plus a strip of fb+fog.
First, I insert the darkslide 1/5th of the way (for the unexposed stripe) and make an exposure at Zone I. Then the slide is pushed in another 1/5th and I repeat that Zone I exposure (results in Zone II on the film). Insert the slide another 5th of the way and open one stop for the next exposure (Zone III on the film). Repeat that last step for the next stripe, i.e., insert slide, open one stop and expose (Zone IV on the film). That uses the first sheet for five stripes: Fb+fog and Zones I-IV.
For the next sheet, pull the darkslide completely and expose for Zone V. Insert the darkslide 1/5th of the way and repeat that same exposure (results in Zone VI on the film). Next, insert the darkslide, open one stop and expose (for Zone VII). Repeat this last step (insert and open one stop) for the next two stripes (Zones VIII and IX). The second sheet has five stripes, Zones V-IX.
The developed sheets get printed (I enlarge them to take enlarger flare into account because I enlarge; if you contact print, then contact print your negs) at "proper proof" exposure, i.e., minimum exposure to reach acceptable max-black from the fb+fog stripe. Then you can easily see where all the Zones fall and tweak your development scheme(s) as needed to get Zones III and whatever target Zone you're using for highlights in the place you want them.
Keep in mind, that this test doesn't reproduce a scene with many different luminances exactly, but it'll get you in the ballpark. Keep good field notes and adjust as needed.
And, as xkaes points out, you really need to kind of standardize on paper and paper development before making your Zone Rulers. Plus, film speed will change ever so slightly with different developing times, so you may want to repeat a particular ruler at a different E.I. if you need to refine the shadow values.
Best,
Doremus
faberryman
10-Jul-2017, 12:02
Dare I mention reciprocity failure in calculating the exposures?
Jac@stafford.net
10-Jul-2017, 15:50
Permit dissent. The Zone System today is a wasteful distraction
Can elaborate.
.
If you are interested in the Zone System, I'd suggest 2 books:
Photography: CONTROL & CREATIVITY by TL Bollman & GE DeWolfe
handbook for Contemporary Photography by Arnold Gassan
If you are really interested in the Zone System in depth:
Beyond the Zone System by Phil Davis
If you are historically interested in the Zone System
ZONE SYSTEM MANUAL by Minor White
Personally have been shooting B&W film, processing it in Diafine, and making digital negatives to contact print from with Platinum/Palladium, Salt, or Fiber base "conventional" paper. Really only now use the Zone System for determine exposure, but having done the complete Zone Testing several times over the years, what I learned still greatly effects my photography. If for any other reason, learning the Zone system allows photographers to converse with each other using a common language of tonalities.
just my 2 cents....
Permit dissent. The Zone System today is a wasteful distraction
Can elaborate.
.
Please do....
Dare I mention reciprocity failure in calculating the exposures?
Apparently not. The quicksand doesn't need more water!
Permit dissent. The Zone System today is a wasteful distraction
Can elaborate.
.
Do you mean, somehow, it WASN'T yesterday?
Peter De Smidt
10-Jul-2017, 16:55
For the most current and comprehensive book on BW photography, see: https://www.amazon.com/Way-Beyond-Monochrome-Traditional-Photography/dp/0240816250
For the most current and comprehensive book on BW photography, see: https://www.amazon.com/Way-Beyond-Monochrome-Traditional-Photography/dp/0240816250
No offense, but why not add IMHO?
Peter De Smidt
10-Jul-2017, 17:06
No offense, but why not add IMHO?
That would be redundant.
That would be redundant.
Superfluous, perhaps, but certainly not redundant.
Bill Burk
11-Jul-2017, 15:30
167123
Here is my data card from such a test series. I mounted a 35mm body to front of lens to get "quartz" controlled shutter speeds. That wasn't a totally bad idea but it caused vignetting that led me to conclude my EI should be 64 for TMY-2.
It was a lot of work and got me Tungsten test results.
I included reciprocity failure information.
One valuable takeaway from this test. You sure learn the logarithmic nature of exposure after making several runs of this.
A seven-dollar Stouffer scale is so much easier.
Who disturbs the peace as a pebble disturbs a pond? Ed Gruberman? The Zone System is a journey towards the horizon not for beating people up.
167123
A seven-dollar Stouffer scale is so much easier.
Who disturbs the peace as a pebble disturbs a pond? Ed Gruberman? The Zone System is a journey towards the horizon not for beating people up.
I've saved a lot of time -- and learned a lot -- from using Stouffer and Kodak scales. I still will -- time is money.
He who moves a grain of sand in the desert changes the world.
Kevin J. Kolosky
11-Jul-2017, 20:13
See if you can get ahold of a Kodak Professional Photoguide with the gray scale and gray card in it. It has 8 different tones. But remember, there are a couple of stops between shade and sunlight as well, so expose the scale in the shade and in the sun. Develop for the recommended time and temp and make a few contact prints with your chosen paper to get the information you are looking for. 1. Your negs were exposed for too long or too little, and/or 2. your negs were processed too long or too little.
Harold_4074
14-Jul-2017, 10:59
The Zone System today is a wasteful distraction
Possibly, once you fully understand it and have practiced it enough to be sure of that. As a step up from taking a light meter reading and exposing at box speed, however, it has served generations of self- and professionally-taught photographers. Sure, eventually it starts to look like applied sensitometry with hard lessons about process control, but there are reasons why it was introduced so long ago and is still around today.
Thank you for your constructive and helpful comments! I did not know about the existence of Stouffer scales existed! I think I'll try that route just for economy and not blowing through so many sheets of film just to build a zone system ruler. I know to calibrate my film speed and normal development time first, I just wanted to have a very clear sense of every step because I need to plan this all around trips to the darkroom, which is close to an hour drive away! I am going to do my calibration process based off of "Zone System: Step by step guide" by Brian Lav. I find the way he lays out the calibration processes themselves to be the easiest and most straightforward.
As of now, I have it down to four darkroom visits (hopefully). The hopefully part is that because the darkroom is not near me some of the "try it and see" type steps wont work. Most of that is the normal development test.I want to develop all the film at home (where I will be normally) so that the water temperature and quality is the same. If anyone wouldn't mind looking over my "zone system itinerary", I would very much appreciate it!
Step 1) Expose 8 sheets of film. Bracket in half stop increments from zone 0 to zone II. Leave one she Develop normally.
Step 2) Go to darkroom. Determine SCT by printing a gray scale through the blank sheet of film.
Step 3) Contact print my bracketed exposures at SCT and determine which one is the proper zone I
Step 4) Go home and shoot a gray card, expose at zone V. Develop one at box time, one 20% longer, one 20% less time.
Step 5) Go back to darkroom and contact print at SCT and see which one matches a gray card. Thats normal development time. Hopefully one of them is right, or at least close!
Step 6) Go home, shoot a fancy stouffer chart, develop normally, go to darkroom and contact print that shot.
Then I have achieved my personal zone system ruler, ya?
Any wisdom is appreciated!
Kevin J. Kolosky
14-Jul-2017, 18:56
I own and have read Mr. Lav's book. Looks like a good way to go.
But you could save yourself some time and film but taking a black card, setting it up on the shady side of a building, metering it for zone 1 at the indicated ISO of your film, shooting it, developing it for the recommended time and temp for your developer, and then reading it on a densitometer to see how close it comes to .10 density over film base plus fog. That way you will know whether you need to either give more exposure or less by altering your ISO. Once you get that on the money you can use the corrected ISO to meter and shoot a gray card in that same shade. Develop it and read it. Should be close to about .65 or so. If not, alter the development either way until you get there.
Kevin, thank you for your reply! That does sound like it would save on my shotgun approach but I do not own a densitometer. I wouldn't know where to start with obtaining or using one either!
Bill Burk
14-Jul-2017, 22:08
Sounds like 1-5 are right from the book, a good deal of work, but you will probably get a good understanding from following a book you trust.
The T2115 21 step Stouffer scale would be used for a test series to replace all those steps, not something to follow-up with.
But for seven bucks, you should get one anyway and place it next to your negatives when you make contact prints. A Stouffer scale can work like a densitometer. You look for grays in the print that match the number... and since each number is a certain density... that part of your negative would be "that" density.
Pere Casals
15-Jul-2017, 05:33
The Zone System today is a wasteful distraction
Possibly, once you fully understand it and have practiced it enough to be sure of that. As a step up from taking a light meter reading and exposing at box speed, however, it has served generations of self- and professionally-taught photographers. Sure, eventually it starts to look like applied sensitometry with hard lessons about process control, but there are reasons why it was introduced so long ago and is still around today.
I Fully agree. At the end film photography is exactly explained by sensitometry graphs, and IMHO, Zone System is a sound way to predict results, or to select an exposure and a development.
By viewing AA prints... no one can say ZS has a flaw !!!
But it is also true that there are advanced concepts to manipulate tonality with CRM/SCIM etc masks, for example. Also split grade printing allows to burn with a different contrast grade...
IMHO ZS is an excellent way to get he core concepts, then IMHO its is useful to read books like Beyond The Zone System and Way Beyond Monochrome.
esearing
15-Jul-2017, 06:11
One thing ZS doesn't seem to teach (or perhaps I have missed it) is how to treat scenes of mostly bright tones or mostly dark tones. Example: Meter some light rocks and a bit of bright southern sky at EV 11-16. Now where do we place this on the Zone System?
Traditionally I would place EV 11 on Zone III and let the sky fall on Zone VIII. This would give me a decent print but might be a bit darker than what my eyes actually saw. I would have to resort to some split grade printing to reduce contrast and print a bit brighter.
These days I want the light areas to be lighter when printed so I would set the EV 11 at Zone VI and EV 16 will fall at zone XI, which would require me to compress the negative so that my highlights fall back to zone VIII without moving the mid tones much. So I end up with a negative that is now zones 4.5-5 through Zone 8-8.5 (+or-), a little flatter, but can still be expanded with MG filters as needed.
Where I'm still struggling is scenes with many dark tones such as heavily forested areas surrounding a sunlit waterfall. I want texture/branch details in the shadows but still want them dark and do not want to blowout the light on the water. Usually only 6-7 stops EV but placement requires some guessing and experimentation for arriving at the right compression (or not).
Trying different papers is making me work harder to find my "perfect negative" too. Ilford MGFB Art is much different than MGFBClassic and MGFBWT in tone, texture, and contrast. Not to mention it responds differently to filters and exposure time in the enlarger.
But the Zone system does give me a method to think about tonalities of scene, negatives, and paper that help me make adjustments. The Nerd side of me wants a densiometer.
Bill, Chapter 8 of Mr. Lav's book suggested that you produce your own gray scale as a final test of your process. I ordered a scale and then by shooting it and developing it my print of the scale should match the scale. I would like the final confirmation that I did everything right!
esearing, have you read "The Art Of Photography" by Bruce Barnbaum? He goes much in depth of maintaining detail in your dark scenes while maintaining highlights. He shot a lot of English Cathedrals which is a lot like your dark forest with a sunlit waterfall as far as dynamic range. Bruce suggests placing shadows higher on the scale since your negative will maintain detail well past zone X. He uses a special compensated developing as well to compress the negative. Then you can always print down and employ Dodging/burning to fine tune your tonalities.
What Bruce tries to convey is that the 10-stop range of the "the zone system" is print based. Your NEGATIVE, however, has a much MUCH larger range to maintain detail. Its just a matter of getting that to end up on paper.
Pere Casals
15-Jul-2017, 08:37
One thing ZS doesn't seem to teach (or perhaps I have missed it) is how to treat scenes of mostly bright tones or mostly dark tones.
Of course ZS is not to tell you in what Zone you should place an scene area, this is your decission.
What ZS tells is what will happen if you place an area of the scene in an exposure Zone. (... Z-IV you conserve detail, but absolutely no detail in Z-0.)
The other important thing ZS tells is that by underdeveloping or by overdeveloping you can get a suitable amount of contrast to print without great complications
At the end ZS is about spot metering, if one wants to meter in a different way (incident light metering...) then other practical rules have to be used.
Kevin J. Kolosky
15-Jul-2017, 08:43
Kevin, thank you for your reply! That does sound like it would save on my shotgun approach but I do not own a densitometer. I wouldn't know where to start with obtaining or using one either!
I own one. send the negs to me and I will read them for you.
And by the way, you don't need to call it the zone system. You can call it the find my correct ISO and development time and develop more or less depending on the contrast of the scene system.
Bill Burk
15-Jul-2017, 10:41
Sounds like you expect the scale to match the print... Don't expect that.
But don't sweat it. Just do the tests and come to your own understanding.
Sounds like you ordered a cameraman's gray scale. That scale only matches the scale of a print in a flat-copy scenario. It has about 5 stops of range, from black to white. A real picture has more like 7 stops of subject luminance range, there's 5 stops from black to white of everything in the sun, plus there's a couple more stops of darker subject in the shade... So when you print a full range 7 stop picture it will compress to 5 stops on the print. Black on the cameraman scale in sun will be a dark gray on the print (with some things darker still on the print) and 18% gray will rise in value a bit because of the "distortion" of tones necessary to fit your full scale negative on the print...
Bill,
I was ordering the WBZ9. It should yield all the tones I need for this test, or at least thats what Stouffer leads me to believe. Now I thought the goal was to get your process to be able to replicate the 10 steps of a scale?
You can call it the find my correct ISO and development time and develop more or less depending on the contrast of the scene system.
You nailed it, but we need to come up with a catchy name for it. How about the ENOZ system?
The Nerd side of me wants a densiometer.
You may have one and not know it. There are many hand-held meters, enlarging meters/analyzers, etc. that can be used under an enlarger -- or anywhere else -- to measure density.
OK, so they can't be used to determine how dense I am, but otherwise they work pretty good.
Bill Burk
15-Jul-2017, 14:31
That's not I V IX. They're a good company with great friendly people so I am conflicted about offering criticism. When you get it, meter the black and white in relation to Zone V. It's likely Zone III to Zone VI but it might be a fraction.
I'm sure you could meter the black and place it on Zone I, etc. But Zone V will fall somewhere else. Your meter will tell you where it fell. So you can use it, it's just not an eight stop spread. Reflection targets just can't be.
Bill Burk
15-Jul-2017, 14:40
OK, so they can't be used to determine how dense I am, but otherwise they work pretty good.
A bone densitometer can tell you that.
Kevin J. Kolosky
15-Jul-2017, 18:21
The main thing is to get yourself in the ballpark. Who cares what zone you call it. Start out with something that has worked for somebody else and then refine it to where you want it with your procedures and your equipment and your materials.
Bill Burk
15-Jul-2017, 19:24
Actually it looks like they put density values on the gray scale on the right-hand side and their Zone IX white might be the top / Zone I black might be the bottom. If so we can figure out what zones they really are.
Bill Burk
15-Jul-2017, 19:56
Here's where I would think Zones would be on a shooting target.
Your target might have a few of these values.
Zone VII+1/3 another 0.1 less = 0.04 (about as white as you can make paper)
Zone VII = 2 stops, another 0.3 less = 0.14
Zone VI = 1 stop, 0.3 less = 0.44
Zone V = 18% = 0.74
Zone IV = 1 stop, 0.3 more = 1.04
Zone III = 2 stops, another 0.3 = 1.34
Zone II = 3 stops, another 0.3 = 1.64
Zone I = 4 stops, another 0.3 = 1.94
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