The contrast and density of negatives and copies depends on the exposure it was given and the time and temperature of developement. Pushing film is compensating a lack of exposure with extra developement, though this produces shadow detail loss, greater grain, etc. Now the question... time and temperature are usually compensated as if it were the same to develope for 10 minutes at 68 degrees and to develope for 7 minutes at 75 degrees. Asuming that the compensation for the contrast index is done correctly, waht difference should I expect from negatives/copies developed in colder or warmer developer?

-- Martin Corvetto (mcrove@iname.com), July 11, 2001

Answers

It depends.

When I asked the same question years ago in rec.photo.something, someone responded me with "it depends." I thought it was because that guy didn't know, and I paid attention to the results I get with different film/developper combinations. Although I didn't repeat all combinations I tried enough number of times to get statistically convincing result, nor did I try to compute the confidence associated with my answer, but my results imply that some developers increase speed or decrease contrast when temperature is raised, whereas some others do the opposite. Some do not seem to be sensitive to temperature change as long as the processing time is appropriatelly compensated.

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), July 12, 2001.

A raise in the temperature of your developer acts as a catalyst in the chemical reaction that happens, making your developer act FASTER. That means that your chemical will be attacking the exposed silver halide crystals more actively, as if it was a stronger developer. Usually this would mean that the silver halide crystals will react by gathering toghether in larger "grains"... I don't think that this applies to all developpers, but with some it must be like that. Try it out and compare the grain structure of two films you will develop in different temperatures (but taken care to have exactly the same Dmax) and share your observations with us.

-- George Papantoniou (papanton@hol.gr), July 12, 2001.

Ryuji's Answer is pretty much spot on, but I'm afraid George's answer is almost completely wrong.
Increasing the temperature of a developer doesn't necessarily result in larger grain clumps, at least, not for the reason that George gives. Silver grains do not move about in the emulsion, contrary to poular belief.
If there is an increase in grain, it's for the following reasion: Many common developers contain two developing agents, usually Phenidone or Metol coupled with Hydroquinone. The two developing agents react slightly differently to temperature change, and this results in the overall character of the combined developer changing with temperature.
These 'superadditive' developers are designed to work at around 68 to 75 degrees Fahrenheit. If you use them outside of that narrow band, they may give unexpected results, such as increased contrast or grain, but not necessarily.
Other developers, which contain only one active agent, will behave more predictably with temperature.
As Ryuji implied, testing all developers at all useable temperatures is an almost impossible task, so detailed information on how a particular film/developer combination reacts over a wide temperature range is sketchy, at best.

A footnote to this about developers based on Paraminophenol, (eg: Rodinal):
The natural hardening effect of P-aminophenol means that it can be used at higher temperatures, and it's used in special 'tropical' developers, which are designed to be used at high processing temperatures.

-- Pete Andrews (p.l.andrews@bham.ac.uk), July 12, 2001.

Thanks, Pete. You're right, the grain increasing effect does not always occur (as I also stated). In the "Focal Encyclopedia of Photography" (Stroebel, Zakia) it is mentioned that it happens with older film emulsions, due to the swelling of the emulsion at high temperatures (Pg. 208). In Rivhard J. Henry's "Controls in Black and White Photography" an experiment is discussed, where Kodak Tri-X developed in D-76 1+1 is developed at high temperatures and where grain and acutance show a great increase at temperatures over 78 Farheneit. In the same experiment, Panatomic-X and Royal-X Pan show no significant changes when deleloped at a high temperature (pg 221 and Table 7-2). As for the sympathetic technique described by Barry Thornton in his "Edge of Darkness" book, it is stated that using Diluted Perceptol (for higher acutance due to accentuated edge effects) at a high temperature results to a slight grain magnification (pg. 90)...

-- George Papantoniou (papanton@hol.gr), July 13, 2001.

I read Henry, and my informal interpretation of his result is that it doesn't mean much. He didn't seem to have indicated the number of measurements of each data point, and the contrast was not adjusted to a single value but was instead set anywhere in some range, etc.

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), July 15, 2001.

While pushing film or developing longer to increase density & contrast for alt process negatives, if you don't have the shadow detail in the initial exposure you won't have it no matter how much you push or at how high a temperature you use. The shadow detail is a function of the initial exposure and the film design characteristics. Some films will give more shadow detail with the same exposure as others that give little. I agree the overall quality changes with time and temperature changes. Especially radical ones. But basic exposure to assure detail in the shadows changes little unless you expose enough to push the shadows further up the scale where time, temperature and developer dilution will work on them a bit more. I got rid of a lot of worry when I moved to development by inspection. This way I can watch the detail & density as it develops. I keep the developer close to 68-70 degrees mainly because my darkroom is normally at these temperatures. It does go up to 75 on occasion but I have not done any tests to see what the exact difference would be. Maybe I should. But I don't see any noticable difference between colder and warmer development. I don't change anything about my development unless I can actually see a measurable change. Getting bogged down in meaningless minor increments only keeps me from concentrating on the image and, for me, is a time waster. Run a few basic tests & see what the temperature difference does for you. Unless the change is measurable... you can actually see it in the final print, it isn't worth doing much more on it. If you can see it then pursue it further & refine it to the point where you have a new creative tool to use.

-- Dan Smith (shooter@brigham.net), July 15, 2001.