Zonesystem testing question

[Andrea Mrazkova]

Hi,

I have a question regarding the zonesystem testing. It is necessary to estimate especially the proper ASA and normal development time for the film in certain developer. But all these values seem too relative and dependent on each other, so what to choose as a starting point? Steve Simmons in his book recommends choosing a scene with normal contrast, place the dark area where we want detail on zone III and make 3-5 exposures, each with different ASA. O.K., but how can I find out now what the real ASA is when I don´t know the normal development time yet. I may develop it according to the manufacturers recommendation but as I could read the real normal development times for various films in the same developer vary widely. And I´m not talking about the proper estimating where zone III really is. What if I estimate it wrongly and put it by mistake on zone II or IV? In this case, isn´t for the tests more precise to take reading from the grey card? Chris Johnson in his book about zonesystem recommends: "Expose for the shadows, develop for the highlights". I think this is because in this way we can give the picture the contrast as we want, and we can make things darker or lighter according to our wish. So when he says "put shadow on zone III", does he mean I put it where I WANT to have it, not where it REALLY is? I suppose so. But for the tests, should it not be where it REALLY is?

[Louie Powell]

Adrea -

You are quite correct that EI and development are interrelated. But the good news is that EI controls mainly shadow detail, while development is more concerned about highlights. That means that there is a fairly simple process to determine these two variables.

Step 1: To determine EI, you need to determine the exposure required to achieve Zone I density. To do this, you photograph a neutral subject (a sheet of blank mat board, or a white wall, works just fine). Start the process with the assumption that the EI is the manufacturer's rated film speed, meter the subject, and then expose as though the subject were Zone I. That is, after metering the subject, give the film four stops less exposure than indictated by the meter. Then, give repeated expousures, decreasing exposure in convenient increments - half stops work well. Process the film, and then compare the density of these negatives with the density of a reference negative that is processed with no exposure. The density of this reference negative represents the natural density of the film base plus any fogging that accumulates during processing. When you compare this reference to your test negatives, you are looking for a negative that is 0.1 density units above the reference - the effective speed at which you exposed this negative then becomes your standard EI. Typically, it will be about half the manufacturer's rating.

The next step is to determine a standard development time. To to that, repeat the test exposure series, but this time expose as though the test subject is Zone VIII - that is, give three stops more exposure than the exposure metered at your new standard EI. Develop this negative. Now, make a test print of the unexposed but processed reference negative. Gradually increase the printing exposure until the black from the reference negative no longer increases density - that is the exposure that yields maximum black from film base plus fog. Then, print the test negative at this printing exposure, process and dry. You are looking for a test print that shows only perceptable detail above the base white of the printing paper. You may need to make several test negatives, developing each for different times (choose significant variations in time - say 30 seconds - for this round of testing). The negative development time that produces a negative that prints a barely perceptable shade darker than the base white of the paper is your standard development time.

Having done that testing - go out and make real pictures. There is a risk of becoming a Zoneie - someone who spends his life testing to determine the ideal EI and development time, but never uses that information to produce real images. You really don't want to go there!

[Leonard Evens]

There are two separate issues here. For both of them, I recommend Adams's original method as described in Appendix 1 of "The Negative".

First, you need to determine the film speed for your equipment. You start off with the manufacuter's recommended film speed. You set up a gray card, determine the exposure for that with your meter, which would correspond to Zone V. Now stop down four additional stops, which would put the gray card on Zone I. Make one exposure with that setting. Now make a series of exposures in increments of 1/3 stop in both directions: 1/3 less, 2/3 less, 1 stop less; 1/3 more; 2/3 more, 1 stop more. Next develop for normal development according to the manufacturer's recommendations for the film and developer. Ideally, you should examine the results with a densitometer. The proper exposure is that for which Zone I is aobut 0.1 above fog+base. Without a densitometer, it is harder, but the idea is that Zone I should be just above absolute black. Some of the references you describe will have ideas about what to do. You adjust the film speed accordingly. Each 1/3 stop corresponds a shift to the next lower/higher ISO film speed.

AFTER determining the film speed, you determine what for you is normal development. You use the same gray card method, but here you concentrate on Zone VIII. You make several identical exposures after opening up 3 stops more than the Zone V exposure on the gray card indicated by your meter. You then develop them for different times at a standard temperature and examine the results when done. Just what density you should get depends on what you do with the negative afterwards. Adams recommends 1.25-1.35 above base for a diffusion enlarger 1.15-1.25 for a condenser enlarger. Again, if you don't have a densitometer, there are other approaches described in these sources.

After you have determined what for you is normal development, you may want to iterate the process to check your results. Changing the development time should not make a large change in film speed, it may make some difference. I doubt if more than one iteration of this process will be necessary.

[Leonard Evens]

I should have added that placement on Zone III for shadows and development for highlights is what you do when taking pictures, AFTER you standardize your procedures for film spped and normal development. However, in actual practice, where you place any particular value depends on the specific scene. You may for example have important Zone iV and Zone VI values which you want to get right.

[KenM]

Another way of determining your film speed and development times can be done in one step with a step wedge. Place a 4x5 step wedge (Stouffer is a good place to get one) and a piece of film into a standard holder (it'll be snug), and expose the negative while pointing at a light surface (such as a mat board). Expose the negative at 5 stops more exposure than your meter reads, using the manufacturers ISO. This will give you zone 0 through zone 10 exposures in 1/2 stops on the negative. Develop the negative as per the manufacturer, and then read the step wedge with a densitometer. The first step that reads 0.1 over fb+f gives you your speed.

Ideally, if the EI matched the ISO speed (doubtful, but can happen) the third step in would be 0.1 over fb+f; this is the zone 1 step, and determines your film speed. If you have to go further to the right (steps 4, 5, etc), each step is a 1/2 stop, and you adjust your speed accordingly. Likewise, if you have to move to the left (doubtful), you increase your film speed by 1/2 stop for each step.

Once you've determined your speed, you can then look at the corresponding zone VIII step (14 steps/7 stops to the right of the zone I step), and determine if that step is 'dense enough' to give you the whites you want - you can do this by either reading the step with a densitometer (you want about 1.35 for diffusion, 1.25 for condensor, but this is based on your materials and preferences), or by enlarging the negative and doing the 'minimum exposure for maximum black' on the zone I patch. Then look at the zone VIII patch, and see where it sits with respect to pure paper base white. Too gray, you need to increase development a bit; blown out, reduce development a bit. Stir until correct consistency :-) When printing, use Grade 2 constrast grade. This is the target that you're shooting for, at least to begin with.

Remember that you should, when testing a film for the first time, always start from the manufacturers *guidelines*. Then, adjust as needed.

Hope that helps!

[otzi]

If one can locate a 0.1 (1/3stop) neutral density filter of any sort, it can be used to give an idea of base + fog + 0.1 for your zone1 by laying it over a portion of clean base and eyeballing it. Not teribly high tech but in the ball park.

[Tom Westbrook]

I find that with Tmax films (at least with 100Tmax) that personal EI is fairly sensitive to development time. I've had to shorten Kodak's recommendation in order to get an reasonalble EI. For instance, Kodak's recommendation for rotary processsing 100Tmax in Tmax-RS 1:9 at 24C is 12 1/2 min (do they mean a Jobo or something else here?) . Most others seem to use times in the 7-8 min range. If I had believed my first test using Kodak's time I would have gotten an EI of around 200. So, don't be afraid to modify development times if you feel that's what's needed.

[pdwcolumbus]

Question: How many zones do you really think you can achieve in a good black and white photograph? And What size negitive whould it have to be? I always thought zone 2-8