How do you TEST film?
I read over and over that a poster is testing a certain film. Obviously, that means different things to different people. To me it means establishing a range of E.I.'s and development times to deal with a variety of scenes using a single developer. If that is what testing means to you I would be grateful to know how you go about pinning down those two variables.
I do a series of practical zone system tests usually using 35mm film initially, finding my optimal dev times & EI to print on Gd2 Ilford Multigrade. I then interpolate this by experience for the same film emulsion in 120 & LF. The first time you do the tests is the hardest. Usually it's unnecessary to do a full set of tests for every new film/developer combination.
I follow a testing scheme along the lines of that described by AA in his book The Negative.
First off, I get an idea of the likely EI for one of the developers I use by shooting a couple of normal(ish) contrast scenes in half stop steps from -1½ to +1½, and then process for a standard time (I like dev times in the 10 minute range, so 10 minutes for the first test). I then do a contact sheet, like Ian Gd2 on Ilford Multigrade, if I am using a staining developer, I will also do a contact on an Argyrotype. After evaluating the negatives, and the contact sheet(s), I will select an EI, and development time to test further. I ususally do this first test using 120 film in a 645 camera.
Next I will tie down my EI for the selected development time by testing for a zone II exposure. I do this using 4x5 sheet film, as I have a set of four old dark slides modified for testing (see attached). Each has a 20mm hole bored in it, each one in a different position up one side of the slide. These allow me to make eight individual exposures on a single sheet of film. I do a series of exposures in 1/3 stop steps around my expected zone II exposure, along with a zone VIII and zone IX exposures. Process, and do contact sheet(s). Often I will just evaluate these by eye, though I do have a densitometer.
I don't usually do extended, or contracted development tests, as my original roll film test gives me enough info to modify my exposure/development for high or low contrast scenes. But if I do these tests, I use 4x5 sheet film in the modified holders again.
Like Ian, I don't test every format of a given film, but the first time I shoot in a different format, say 35mm, I will evaluate the results carefully in case I need to make any adjustments.
Last edited by snallan; 02-02-2008 at 07:13 AM. Click to view previous post history.
Reason: Must learn to spell!
"You don't need eyes to see, you need vision" - Maxi Jazz
Steve - when you visually evaluate your z2, z8 and z9 contacts how would you describe the density/tone you are looking for in each case?
There are so many different responses you can expect from this question with folks putting their own twists on it. It's a sure way to be driven crazy. Your question is best answered by getting any one of several different references on film testing and following it. Getting support and being helpled through a known and established testing procedure is, IMHO, a more valuable use of time and resources than trying to test using multiple variations and personal twists. This is not to mean that those variations are not valid for the individual, those personal twists may come from years of experience.
I would get AA's The Negative to learn how to test, but more importantly, why you test. Or, John P. Schaefer's "The AA Guide, Book 2 (the same title with Book 1 from Schaefer is good too but does not go into testing, but does have great supporting info on the zone system). Book 2 provides ways of testing without using a densitometer, but if you can score a reliable densitometer from ebay at a reasonable price, then testing is much easier and a more straight forward process. If you are using 4x5 film, testing using the method in Book 2 can be completed in just one sheet for determining the EI and then another 5 or 6 sheets to find the developing times.
Oh, and not to leave out those Beyond The Zone System folks, you might want to explore the BTZS method of film testing, but I don't know much about that system.
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Fred Picker made this process simple for people in his book The Zone VI Workshop that came out in the 70s. It helps you estab. your own EI and dev. time. If you can find a copy of that book get it.
It will not meet the needs of some people for absolute, controllable science but Picker's method has been used by thousands of photographers for 30 years very successfully.
The key is to match your film, film developer, printing paper and to some extent the print developer. These are a team.
Zone 1 in the film should have a density approx .01 above film base plus fog. This will create a tone on your paper just barely perceptably lighter than pure paper black. Zone 7 or 8, whichever you prefer, will have a density between 1.25 and 1.5 and be the densist area on the film that produces a tone just barely perceptably darker then pure paper white.
IMHO you can't do this with a densitometer. The film and paper have to be matched and so the upper end density numbers are not an absolute. I use a vc paper w/o a filter which is about the same as a #2 filter to standardize on.
Last edited by steve simmons; 02-02-2008 at 08:52 AM. Click to view previous post history.
Chuck: Testing with BTZS is quite easy, and considering the time one can save, cost effective. I have no affiliation with Fred Newman and BTZS/The View Camera Store other then taking a course with him, and using his film testing service. Briefly, Fred will send you film to be developed in your own darkroom using your own methods. He will make some suggestions, if you desire, regarding developer and dilution. At any rate, you chose the film you want to use, and Fred will expose the film using a step wedge. The film ( 5-6 rools or 5-6 sheets ) arrives at your door, and your develop the film at various times using your standard methods for each sheet, or roll. Then one mails the developed film back to Fred, who will do the densitometer readings for you, and plot the data. From the curves one can derive the correct film developing times for the subject brightness range and exposure parameters for each expoure you make. Fred can tailor the curves for your use in either BTZS which emphasizes EV values, or the traditional Zone system. If desired the data can be entered into a very convenient program as developed by the late Phil Davis, or the data can be easily applied using a very cheap Power Dial. As needed, the program can be entered onto a hand held computer device such as a Palm Pilot which can conveniently be taken into the field and very easily used to quickly provide one the exposure needed ( including, as needed, filter factors and bellows factors ), developing times, etc. Obviously there are other methods ( as outlined here by well known and knowledgeable posters ) to derive the same data. However, BTZS certainly has definite advantages.
Rick, consider the time you have, and your level of expertise, before you make a final decision about how to proceed. Best of luck, and let us know how you make out.
Last edited by Mahler_one; 02-02-2008 at 09:21 AM. Click to view previous post history.
FWIW in recent years I've been film testing by setting up a black camera bag and piece of white, textured polystyrene outside in even lighting. I toss in a grey card for good measure. I run exposures from ISO - 2.5 stops to + 2.5 stops in 1/3 stop increments. I develop the film at my best guess - actually at Massive Dev. Chart!! - and proof at the usual minimum exposure / maximum black. From this I look for the best rendition of the black bag.
I then print 8x10's of the selected exposure and the one each side of it on my normal contrast paper - exposure is again min.exp. / max. black. I select the print that gives me a truly black bag with textural details. Usually one of the prints shows wonderful texture - but isn't black. Another is truly black but shows no texture. Printing the three makes the decision easier - for me at least. If I'm truly conflicted I opt for the lower indicated E.I.
Next, look at the polystyrene on the selected print. It needs to be truly white - but with visible texture. If it's dingy - increase your film development time. If it's lacking texture - decrease.
I've used this for a while and it works for me. I did "do" the ZS for a some time but it didn't suit me in the field. I also went through BTZS and again it didn't suit me in the field and I also found myself holed up in the darkroom without creativity. This, I feel, cobbles together thoughts from both, (and others) and works for me. I can shoot and develop a test roll of film in an hour or so. Once it's dried, it takes no more than an hour to print the tests. Trying a new film / developer combination now is no longer a daunting task.
Mostly, I would advise you to get to understand the underlying principles: Why minimum exposure / maximum black? Why expose for the shadows / develop for the highlights? The effects of different types of developers, different agitation etc. In this way, you can truly learn to create the "feel" you want to achieve in your work.
Hope this gives you some food for thought.
"Why is there always a better way?"
Hi Rick, the z2 I evaluate on the negatives, and I am looking for the first patch that gives me a tone that is easily perceptible against the surrounding film. I will often have a patch that I can make out if I hold the neg against the right light source, and squint at it from the right direction. But if I have to do that, it's not the right exposure
For the z8/z9. I partially mask those patches on the negative when I am making my contacts. For the z9, I am looking for a tone that is just perceptible from the masked area of the contact print. For the z8, I am looking for a definite, but very pale grey.
"You don't need eyes to see, you need vision" - Maxi Jazz
Bob - your method makes a great deal of sense to me and pretty much mirrors what I have been doing. I never could understand the fixation with Z1 nor the target densities for the higher zones. My shadow readings are primarily placed in Z3 and 4 so I aim for an E.I. that will reproduce those areas with my paper, developer and enlarger in the way you describe your black bag using my SPT. My targets are a black T shirt, a white T shirt and a gray card. Noting where the meter reading of the white T shirt fall I adjust my development time to match my mental picture of that value be it Z7, 8 or whatever just as you judge how you polystyrene looks in print. Until you described your approach I never remember reading about adjusting exposure and development based on photographing and printing real world textured objects. I was well aware of the FB + fog approach but was hoping to hear more of the methods others have adopted to personalize their results. My method seemed too simple but it's good to know someone else apparently has come to some of the same conclusions. KISS! Maybe someone can convince me that buying a densitometer and 100 sheets of graph paper really does make sense.