Originally Posted by Ray Heath
One sheet, check trusty Weston meter is accurately zeroed, and you have metered on the zone you want.
Spend ages looking at neg and test print.
That is how the master worked.
P.S. read the book first...
I think he wants to do a full Zone test.
1) Zone III at ISO -1 stop
2) Zone III At ISO -2/3
3 Zone III at ISO -1/3
4) Zone III at ISO
5) Zone III at ISO +1/3
6) Zone III at ISO +2/3
7) Zone III at ISO +1 stop
8) unexposed for FB but most would use the film rebate for this I bet
A bunch at Zone VIII but most would wait to do this until Zone III is figure out. FWIW I think most would ignore box speed and above also.
I'm sure I'm missing something.
Beat me! You can easily get three exposure tests on a single sheet of 4x5 that are nice and large areas. Just take good notes while doing this so you don't just create a pile of crap.
Originally Posted by JBrunner
For a developing test, you could cut your 4x5 sheet in half, I wouldn't do thirds. That saves you a bit of time and some money on the materials.
If you were doing 8x10 testing, I'd suggest just getting a box of the same stuff in 4x5 and testing on that with a conversion back or hell, just tape them into the 8x10 holder.
Testing for 4x5 by substituting roll film could be a disaster if there are any kind of formulation differences in the emulsion when they switch support materials.
Forgot to add, Steve Simon's article in the free downloads at ViewCamera.com is a nice, simple distillation of film testing. And as a bonus, to do it you also do some basic printing time testing to get "maximum black". You will also need to know that for your single grade of paper and its developer too.
Fomapan 100 5x4 and 10x8 are on different bases (thickness), presumably the emulsion is the same but I don't know if affects anything else?
I use the drilled dark slides in conjunction with a modification of the "Nine Negative Test" when I find it necessary to re-test. One sheet of film gives me the EI, and no more than three others are required to determine development time.
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I'm in a similar boat to you, so let me say that in my inexperienced hands, one cannot translate roll-film EI or dev times to sheet film- the processes and films are too different, I think. Also, I do not believe that one can use the same EI across different developers.
A question for Jason: I'd like to try your method of pulling the darkslide incrementally- How do you calculate the exposures so each one is 1/3 stop different than the previous. It sounds like doing a test-strip using f-stop printing, so I'm pretty sure there's a simple way to do this. Also, since the exposure is building up, rather than having one single exposure, would there be the same "accuracy" problem that people say exists in printing (i.e. 10 one second exposures is not equal to 1 ten second exposure)? Lastly, would there not be a light-leakage/scatter problem along the film where the darkslide edge is pulled? My main problem with film testing has been what looks like uneven lighting, and it seems this method would cause a similar effect.
I just move the aperture 1/3 stop. The EI difference would be calculated from the EI you choose as a baseline, for example 1/3 stop from 200 ISO would be about 160. The accuracy problem is negligible because a shutter opens or closes much faster than an enlarger lamp ramping up and down. There will be a small amount of scatter along the line where the darkslide is positioned, but you will have a good usable strip on the neg. The amount of light getting up under the slide wouldn't be enough to matter, as it likely isn't enough to even engage reciprocity if you don't lollygag around, so for all intent and purposes the area under the slide stays dark. It could be argued that there is some effect, depending on situation, but the variance wouldn't amount to anything that would bother most persons. It all depends on how anal you want to be about exactitudes. I can usually determine a speed/developing combination within three sheets, though certainly not with the accuracy of a full BZTS regimen. I generally extrapolate my full expansion and contraction from my baseline -1 0 +1 testing information, and adjust from field results after that. Some photographer like to test things to the last detail, some just wing it. Most are comfortable, like me, in the middle ground. It's simply individual choice, and in the end, the print is what counts. For some reason, many (not all) of the most technically exacting photographers I am familiar with make limp prints. A good photographer is one who can stand astride both the art and the craft, without half baking, or over baking either.
Originally Posted by timbo10ca
If you change emulsions, or developers, a new round is in order. Since my testing method is based on performance with particular papers, I test new papers with my saved negatives from particular film/developer regimens as well. Basically, if something changes, you need to examine the performance of the new thing. Before I figured this out I might say- such and such film or paper is crud, but the truth is it just wasn't behaving like a familiar friend. Many criticisms of papers, film and developers stem from such things.
Last edited by JBrunner; 02-22-2008 at 01:01 PM. Click to view previous post history.
This is the method I use. The first sheet covers 4-1/2 stop cincrements with the fastest speed being the box speed and the dev being manu recomended. I inspect the film and decide how close I can get to box speed by adjusting development. The second sheet is exposed at the choosen speed and developed at the new time. I inspect and adjust for the third and generally final sheet. Using the dark slide in this manner was told to me by an APUGGER in a similar thread where i asked for help testing some SXX.
Originally Posted by JBrunner
D F Cardwell has thought/told me that semi-stand can be used to achieve box speed with at least one film (TXP). This will be something that I'll be employing in the future on other films, but don't know enough about to be advising anyone.
Sorry that this doesn't help you with +N or -N, but it will get you to the film speed/dev combo prettry quickly.
Ah ha! Didn't realize that one.
Originally Posted by keeds
But like Jason mentioned, you can just pull the dark slide part way out and get multiple tests on a single sheet. I did this for some 8x10 testing and put 4 per sheet. Worked well since I was doing Zone System testing and shot a "blank" wall about 10 feet away but with infinity focus to kill any detail. Just wanted the tone.
I'm almost embarrassed to post this as it will probably make me seem quite thick, but I must be making this more complicated than it is (which is usually my problem). I want to set the stage here:
Originally Posted by JBrunner
1)The way I see it is that when using a set repeating time exposure, it won't matter if the exposures are being made as the slide is pulled out or pushed in, i.e pull slide all the way out give 2sec exposure, cover 1/4 of the film give 2 sec, cove another 1/4, give 2 sec, cover another 1/4 give 2 sec will give a sheet of film with exposures of 2, 4, 6, and 8 seconds. This would be the same if the film is uncovered as the exposures are made. I make this obvious point, because when f/stop printing, the test strip must be covered, and not uncovered as exposures are made. This leads to point 2, where my confusion lies:
2)Say there is a base exposure of 1/60 at f11 to give zone 3 for ISO 100.
If multiple sheets were used and exposed individually, the ISO 80 would be 1/60 at f8 2/3 , ISO 64 is 1/60 at f8 1/3 and ISO 50 would be 1/60 at f8. I cannot see how a repeatable building exposure would give 4 successive regions using the single sheet method differing by 1/3 stop, or how one would calculate that exposure to lay on top of that 1st one of 1/60 at f11. I'm sure the answer is obvious, but I just can't get my brain around it. Even in the example of point 1, region 2 will be one stop more exposed than region 1, region 3 is 1/2 stop more than 2, and region 4 is 1/4 stop more than 3..... It seems to me that one would have to be adjusting the amount of exposure quite precisely as the film is covered, like in f/stop printing. Now I've run out of brain powe...
Last edited by jd callow; 02-22-2008 at 06:40 PM. Click to view previous post history.
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