Starting Points for Negative Development Adjustments Based on Complete Tonal Range in the Original Scenegreenspun.com : LUSENET : Large format photography : One Thread
Could some brave soul with darkroom experience venture recommendations for development time adjustments for scenes with subject brightness ranges varying for example, from 4 to 12 stops in terms of percentage deviation from the normal recommended development time? (ie, under these general conditions: Starting with traditional B&W films such as Iford HP5 or FP4+, and traditional D-76/ID11 type developers and with normal agitation at the recommended temperature of 68F.)
For example: SBR 4stops: +10% or 110% of recomended development time. SBR 5stops: 0% or 100% of recomended development time. SBR 6stops: -5% or 95% of recomended development time, or whatever the case may be.
I have yet to see such potentially useful starting points published in this manner. It would personally improve my negative work. Thanks much in advance. Andre
-- Andre Noble (email@example.com), July 14, 2001
I think that before you get 500 individual answers it should be stated that any hard and fast rule will not be hard and fast. That is, it will be subjective. For me, my baseline curve is something I dialed in...through testing, but mostly through fine adjustments over time based on imperical data gathered through using my lens(es). I've found that the one variable that is difficult to account for is the sharpness and contrast of one's particular lens setup in concert with any particular film/developer combination. Perhaps this is why we've never seen such a clever, albeit monstrously large in proportions, idea in print.
And another thing: there is a HUGE difference between Kodak's and my definition of normal development. My normal development for open tray processing of Plus-X in D:76 1:1 is 8 minutes at 80F. I think they say 8 at 68F. Emulsions can be fickle too.
-- Chad Jarvis (firstname.lastname@example.org), July 14, 2001.
O.K. Chad, assuming then, that for a normal contrast scene with a contrast range of 5 stops, and in your setup, you get an optimal negative with a open tray processing of Plus-X in D:76 1:1, 8 minutes using an agitation method you've worked out at 80F.
How much then, percentage wise, would you adjust your developent time if your scene's contrast was 4 or 7, 8, 9, 10 stops, etc?
This is the type of data that I was hoping a couple of B&W experts might venture.
One day soon, when I really know what I am doing, I will pull out all the stops and thouroughly test my film. In the meantime, I want to use starting points of development time based on the interpretation of educated guesses, if possible. For example, I always still cool my developer down to 68F, the pain that it is, just so to minimize that variables. Thanks again all in advance. Andre
-- Andre Noble (email@example.com), July 14, 2001.
Andre, I suggest Steve Simmons' book Using the View Camera which has a good chapter on the Zone System, explaining with clarity how to adjust development for different contrast ranges. Basically, you'd use normal development (which you should test for or arrive at from experience) when there's a 4-stop brightness range from Zone III (shadow areas with important detail) to Zone VII (highlight areas with important detail), or a 5-stop range from Zone III to VIII. Obviously you need a spot meter to measure these areas in your scene. If there is a range that's one stop over what it should be on the Zone scale, you generally would use N-1 (Normal minus one stop) development to reduce density in the highlight areas of the negative. One stop under normal range, use N+1 to increase highlight density (hence contrast). For example, Simmons suggests testing 3 negatives, with very slight adjustments in exposure, at 75, 80, and 85 percent of normal devlopment time to get N-1, then print them to see which one is best. (Pages 90-92 in the book.) A basic starting point for many films is 75% of usual time for N-1 and 50% over usual time for N+1. Simmons gives some guidelines for more extreme adjustment (N-4, N+4 for example). But as stated above, different films react differently to adjusted times.
-- Sandy Sorlien (firstname.lastname@example.org), July 14, 2001.
Andre, As Chad states, hard and fast rules... This is why we test films and papers. There is no real way of getting out of it. Literally what works for someone, may not work for you... even if your really lucky! A friend of mine and I went shooting (same subject) and she went home to process and so did I. Because of the water differences, agitation differences ect. our negatives are different. I will go out on a limb though and say that if you have a 12 stop difference, try a 20% pull on a test. It should be close all depending what you want. You can also use a compensating developer like Divided D76 or even Diafine which only developes your highlights to "their optimum". When all else fails, shoot several sheets and develop one at a time with different pulls or pushes but testing will always be needed for consistency and knowledge. There is no real way to get around it.
-- Scott Walton (email@example.com), July 14, 2001.
As others have said, no one can give you a good answer because everyone's results are different. You need to test for yourself.
For complete instructions and probably more than you ever wanted to know about the subject, see _Beyond the Zone System_ by Phil Davis.
-- John Hicks (firstname.lastname@example.org), July 14, 2001.
Kodak says that Tri-X will record over a 7 stop range, you just have to decide where you are going to place that range. Pat
-- pat krentz (email@example.com), July 14, 2001.
Thanks for the tip on the Steve Simmons book. I went to a camera store today to read the chapter on film development. O.K., this is what I was looking for. Thanks Again. Andre
-- Andre Noble (firstname.lastname@example.org), July 14, 2001.
HP5 and FP4 are nice, forgiving films.
Well said about the subjectivity. Generally speaking, my "normal" development times are
HP5 D-76 1:3 14 minutes, agitate 1st minute, once every minute therafter
FP4 D-76 1:3 13 minutes, agitate 1st minute, once every minute therafter
For me and many zone-system practitioners, "normal" assumes a 5-stop range, with the highlights usually no denser than zone 7 or 8 (good, discernable detail).
For scenes with a wider range, reduce development times approx. 20% per stop. For scenes of 8 stop range or more, you need to use compensating development. Here's what works for me (and what maintains film speed)
n-4: D76 1:4 12 minutes, agitate every three minutes n-5: D76 1:5 12 minutes, agitate every three minutes
Times many vary, though. You should experiment with varied times and agititions. To maintain film speed over wide-range images, expose shadows in zone IV, use high dilutions, longer development times, combined with LOW agitation. This allows the D76 enough time to fully develop the shadows, while allowing development to exhaust in the highlights. Have fun!
-- Chris Jordan (email@example.com), July 16, 2001.
Chris, are you at 68F with your development times and dilutions here? Just curious. And otherwise, thanks for the info, which I may take up as starting points myself. Andre
-- Andre Noble (firstname.lastname@example.org), July 16, 2001.
Woops, forgot to mention that... I use 66 degrees for everything. That happens to be what my cold water tap runs at, and usually I get some drift up to 68 over the time of development (I use trays, which have a lot of exposure to the warmer air in the room). If you start at 68, I'd say take a minute off each of those times, for starters. good luck, Chris
-- Chris (email@example.com), July 17, 2001.