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Don Wallace
23-Feb-2007, 22:22
I am doing some Zone System testing with FP4 in 4x5. I established an EI of 100 and now I am trying to get my development time established but I am getting wildly inconsistent results.

In the first test, I photographed a grey card, out of focus, filling about 2/3 of the frame, placed on Zone VIII. I developed this in HC-110 dilution E (1:47, 6 ml syrup + 282 ml water) at 68F for 5 minutes. The density of the grey card was 1.37 (1.47 - 0.10 fbf). A little high, but I didn't want to go less than 5 minutes. I can live with a little high.

In the second test, I wanted to produce a Zone VIII negative to do some testing with my dichroic head, so I did exactly the same thing, except that I did not use a grey card. I used a plain wall and set the focus at infinity so it would be completely out of focus, and placed it on Zone VIII. Same developer, same dilution, same temperature, same time. The density of the negative was different from one end to the other by quite a bit: 1.75 (!) to 1.50, with an fbf of 0.8, giving a net density of 1.43 to 1.67.

Can anyone see anything obvious here?

Brian Ellis
23-Feb-2007, 23:22
I don't know exactly what the problem is but there are a couple things I think could be done better. First, fill the frame with the gray card. Actually I don't think a standard gray card is the best subject to use, I'd try to use something a little brighter and with a matte finish. The Kodak gray cards I've had produced a surface sheen when placed at certain angles to the light which affected the exposures. Second, use the same subject for all tests instead of a gray card for one and a wall for the second.

I don't necessarily think any of that caused your problems but I think it's good practice to fill the frame and to use the same subject for all the tests. I also think it's good practice to make the different exposures from the same place so that the lens-to-film distance remains the same throughout the tests. It sounds like you didn't do that because you say you photographed a gray card "out of focus" for the first test and then focused at infinity for the second test. Also, was the wall you used for the second test perfectly even, i.e. not stucco or something like that?

You don't say anything about the lighting under which you were testing or how far apart in time your two tests were. I learned the hard way that testing out doors can be very difficult because there can be very subtle lighting changes between exposures. I went through a box and a half of film the last time I did my own testing because I checked the corners and center of the card I was photographing after each exposure using my spot meter and I kept getting slightly different readings all the time so I had to keep starting over. It was that experience that caused me to forget about doing my own testing and let The View Camera Store do the testing for me using the BTZS system. It costs about $30 but I think I spent more than that on wasted film.

I don't know that any of this will cure your problem, without actually watching you conduct the tests trying to figure out what went wrong is mostly speculation but hopefully it will help.

David A. Goldfarb
24-Feb-2007, 04:23
It could be a number of things. Was the wall evenly lit and did you meter it at the same angle with respect to the light for both tests (I assume you used a spot meter)? Was the camera focused at infinity for both shots, and if not, did you include the bellows factor for the gray card test? Was the exposure long enough to cause a reciprocity issue in either case? Did you use the same lens for both exposures, and does the shutter seem consistent?

Don Wallace
24-Feb-2007, 08:04
Second, use the same subject for all tests instead of a gray card for one and a wall for the second. .

I hear what you are saying, but in theory, if you are testing so that you can render any given value at zone VIII, then it shouldn't matter. But you are right - reduce the number of variables.



You don't say anything about the lighting under which you were testing or how far apart in time your two tests were. I learned the hard way that testing out doors can be very difficult because there can be very subtle lighting changes between exposures. I went through a box and a half of film the last time I did my own testing because I checked the corners and center of the card I was photographing after each exposure using my spot meter and I kept getting slightly different readings all the time so I had to keep starting over. .

I had to laugh at this a little because I was just thinking I would have to go outdoors in order to get even illumination, despite it being Canada in February. Thanks for helping me deciding against it.

The reason I didn't fill the frame the first time is because I didn't think it would matter. As long as the image of the card on the negative is big enough to put under the densitometer, I figured that it is placement and development which is the most important. The reason I tried the fill the frame the second time is because I wanted a zone VIII negative for doing some print testing with the colour head.

This morning, I grabbed a piece of 16x20 bright white matte board and tried to find a place of even illumation. There isn't one anywhere in this house. Old houses in Canada in the winter have lots of amazingly subtle changes in light and you can change it dramatically by where you stand. Beautiful and fascinating, but even? Not even close.

But now that I have your attention (I hope), I would like to establish a slightly longer development time. Dilution E takes me right down the limit of rotary processing (5 minutes). Have any of you used HC-110 in greater dilutions? Anything of which I should be aware? Tricks, pitfalls?

Brian Ellis
24-Feb-2007, 09:50
" . . . does the shutter seem consistent?"

David brings up a good point. When I used to do zone system testing and made multiple exposures I tried to start with an aperture and shutter speed such that only the aperture needed to be changed for the different exposures. Leaving the shutter speed the same throughout helps with consistency. But it also brings up another point about zone system testing with LF systems. If you're using traditional testing methodology as you are then in theory you should do separate tests at each shutter speed and with each lens and the tests should be repeated periodically to check for changes in shutter speeds. Of course even the most fanatical of testers isn't going to do that. But it does bring up an advantage of the BTZS system of testing since (if I remember my BTZS days correctly) that system doesn't rely on making multiple exposures with your camera and lenses (which isn't to suggest that everyone should use that system or that it's the "best" system, whatever works for you works).

Brian Ellis
24-Feb-2007, 09:52
" . . . does the shutter seem consistent?"

David brings up a good point. When I used to do zone system testing and made multiple exposures I tried to start with an aperture and shutter speed such that only the aperture needed to be changed for the different exposures. Leaving the shutter speed the same throughout helps with consistency.

But it also brings up another point about zone system testing with LF systems. If you're using traditional testing methodology as you are then in theory you should do separate tests at each shutter speed and with each lens you own and the tests should be repeated periodically to check for changes in shutter speeds over time. Of course even the most fanatical of testers isn't going to do that. But it does bring up an advantage of the BTZS system of testing since (if I remember my BTZS days correctly) that system doesn't rely on making multiple exposures with your camera and lenses (which isn't to suggest that everyone should use that system or that it's the "best" system, just that it does eliminate a variable).

neil poulsen
24-Feb-2007, 10:24
I would use the gray card for all your testing. The wall is probably non-neutral, and film across the zones may have a different response to the wall than to the gray card. That your gray card takes up 2/3rds of the frame is probably OK, as long as you're measuring in the center. Consider using a spot meter to take multiple readings at different places on the card. This way, you can identify the area on the card where readings are indeed consistent.

Also, what are you using for a light source? I've found I get better results when using the blue photo bulbs that one can find in a photo store. They have a short life, but I use them only for testing, and I keep them on only so long as it takes to make the needed exposures. In a way, this makes sense to me, because I suspect that black and white films like TriX, while panchromatic, are daylight corrected.

Consistent zone system testing places demands for consistency in all parts of the process. Here are some sources of variability that I've found which can lead to inconsistent test results. Some of my methods may seem too rigorous. But, they give me consistent results from one test to the next.

>> How consistent is your shutter speed? I've found a speed on my 150mm lens that is consistent within 1/20th of a stop. (It's actually more consistent than this.) When the consistency is there, I've found that the longer speeds to generally be more consistent than the shorter speeds. e.g. 1/2 or 1/4 second, when compared to 1/100 second. I bought an inexpensive shutter tester from Calumet that works very well for this purpose.

>> Developer temperature is also critical to consistency. I control mine to within about a 0.2 or 0.3 degrees. (Even this inconsistency seems too high to me, especially for TMax films.) And to be honest in reporting my methods, I control what variability remains by using a Zone VI compensating developing timer.

>> Methodology. I do things exactly the same, every time. For example, in testing medium format film, I use a temperature controlled water bath around my film canister. I also don't agitate by hand. I use a canister that's double the height I need, and then lift and lower the film cassette up and down in the developer for agitation. This way, I have very consistent temperature and agitation during development.

I also don't pour out and pour in chemistry into the same film canister in proceeding from developer to stop. My film cassettes fit on a wire frame that easily allows me to lift the film up and down inside the canister, and allows me to transfer the cassette from the developer canister to the stop canister for this change in chemistry. But, after the stop, I use a lid, pour out stop, and pour in fixer. Parenthetically, this means that I do my development in the dark.

I'm not sure what methods you use for developing 4x5, which is different than methods used for medium format. The the same idea holds for both. Consistent agitation and temperature are important for consistent results.

Manufacturers with whom I've spoken maintain that medium format film is sensitometrically identical to sheet film. So, one can consider whether they might substitute testing medium format film using a film holder with their 4x5 camera and lenses.

>> In metering, I check my target before and after taking each exposure. If I find prior to an exposure that my lighting has changed, even by a small fraction of a stop, I re-adjust. I built a slider for my lights that is pointed straight at the target that easily allows me to make quarter or half inch adjustments in lights to target distance, so that I can make small refinements in lighting. As I expose from one zone to the next, I change my aperture, change my lights to target distance, and use neutral density filters. I do not change the shutter speed. So, my lights tend to be pretty bright on the target, so that I can achieve from a Zone 10 to a zone I exposure on the film.

>> In reading film, I use a densitometer. This is probably a weak link for me, because I have an old densitometer. But, I check each result, so my data are sufficiently consistent for the purpose. I also check my densitometer calibration before each use.

These are the most important sources of variability for me. Some may say that this level rigor is ridiculous, and that it's not taking pictures. I'd probably agree with them; but, it gives me consistent results. Once I built my equipment, I've found that this rigor isn't that much more difficult than to use less rigorous methods. Anyway, testing is not about taking pictures, which relies on a different part of the brain. Testing is about craft, and good craft enables one to more predictably bring about their particular visualization of the image they want to produce.

Do I try to apply this kind of rigor in the field. No. (I have tables though, that give me actual versus nominal shutter speeds.) How can one? But, my exposures in the field will vary around my test results in a way that, on average, I obtain consistent results. There are too many other sources of variability in the field to be able to maintain the kind of rigor that I use in testing.

As a weak point, I don't do separate testing for each lens. I should probably do separate testing for my Super-Angulons versus my plasmats, picking one example from each category. But, I don't, and I like the results that I obtain.

As a last point, I don't do testing that often. Only when my film changes. Not even when the paper changes. After all, Ansel Adams obtained great results from a variety of papers that didn't exist when the initial exposures were made.

Don Wallace
24-Feb-2007, 21:42
Thanks for all the replies. The earlier test was done with a shutter speed of 1 second, and although the shutter is in good shape, I decided to try it again with a faster speed, just in case. I tried with the large white matte board again (to get a little more room for opening up), this time waiting until later in the day, about 1 PM, and I managed to get a least a part of the board to read consistently. I redid the test making very sure I only used the part of the board that was consistent. Shutter speed was 1/4 second. I developed it right away and, lo and behold, I was right the first time. My development time is 5 minutes. I also tried developing a second sheet with a dilution of 1:63 for 8 minutes. It is a little high, but at least now the negative is consistent from corner to corner and I can develop the other sheets tomorrow.

Thanks for the help. It was either that I was just not paying close enough attention to the changes in light, or the 1 second shutter speed is a little off, or both.

By the way, I got this test procedure from Ansel Adams" "The Negative," where he says to make sure the light is consistent. He lived in the southwest of the US, so I went to Google maps and checked California, Arizona, Nevada, and New Mexico with my spot meter pointed at the monitor. It showed that light in those parts of the US is very very consistent, so Adams probably had an easier time of it. Canada, indoors in the winter, is just not the same. :p

Ken Lee
25-Feb-2007, 09:44
Here's another suggestion: Get a subject to hold a grey card and pose for you. Go out in the sun and each time you shoot at a different aperture, let the person hold up a card on which you write the corresponding film speed for that exposure.


http://www.kenleegallery.com/images/tech/tmypc200.jpg
I did this one myself using a long bulb-release. (TMY at 200 in PyroCat).
Note that all the shadows and high values are within range. Good enough for me.
I brought along a white porcelain tea-pot and stuck my black light meter in the shade.


For FP-4, shoot at ISO 25, 50, 100, and 200. For each film speed, shot 4 shots.

Develop each set for a different duration, but develop them all together if possible. (This is easy if you have an Infra Red viewing device (http://www.kenleegallery.com/html/tech/tech.html#Monocular): you can simply pull out a set of negatives when their time is up, and let the others continue).

In the end, it will be fairly obvious which film speed/developing time gives the most "normal" results. Of course, you need to judge the final prints, according to the way you make them (analog or digital) after dry-down, etc. If you use an enlarger, then you need to enlarge to your typical size - especially since the color of the head, the filters, etc. can have a big influence. It's your water, your thermometer, your choice of chemistry and paper, your style of agitation, your timer, etc.

Skin tones and other familiar objects in the shots, will either feel like light, or not.

Anupam
25-Feb-2007, 09:58
It was either that I was just not paying close enough attention to the changes in light, or the 1 second shutter speed is a little off, or both.

A wee bit of reciprocity might also start to creep in at the longer speeds. Best to use a short speed and then try to change it as little as possible between zone I and zone VIII and only change the aperture.

-Anupam