Critical Temperature

Reticenti · Mar 27, 2007

How critical is it to have the various solutions at a certain temperature? (Isn't it 68 degrees?)
And how would I go about getting the solutions to that temperature once I mix it up if it is important? :confused:

JLP · Mar 27, 2007

For consistency it is important to keep the temperature as close to the same every time. B&W film is not that critical but try to keep all solutions within 1 degree C or 3 degree F.
It does not have to be 68 degrees or 20 C. If you have a problem with hot tap water you can standardize at a warmer temp such as 74F or 23C
You would just need to adjust your developing time accordingly. For every 1 degree C you raise the temperature shorten your developing time with 4%
You can keep you chems in a waterbath to stabilize the temperature. The more water in your waterbath the more stable it is.
Hope that helps.

jan

David H. Bebbington · Mar 27, 2007

Reticenti said:
How critical is it to have the various solutions at a certain temperature? (Isn't it 68 degrees?)
And how would I go about getting the solutions to that temperature once I mix it up if it is important? :confused:

The easiest way to raise or lower the temperature of made-up solutions is to put them in a metal (stainless steel) container (jug or even a spare developing tank) and stand this in either very hot or very cold water. This will produce a much more rapid temperature change than if the solution were in a plastic vessel.

Rick Jones · Mar 27, 2007

Richard J. Henry in his "Controls in Black & White Photography" questioned the claims by some that quality would suffer if all processing temperatures, including washing, were not tightly controlled. He ran three protocols comparing Tri X processed at 68 F and then allowing stop, fix and wash to vary as much as 18 F. He stated all 3 films gave the same CI's and showed the same G (granularity). Good enough for me! "Isn't it 68 degrees?" or how important is it to develop B&W film at 68 F? Dick Dickerson and Silvia Zawadzki are two retired Kodak scientists who write articles for Photo Techniques magazine. In the J/A 2005 issue they addressed this question stating "And whether you use a shorter time and higher temperature or vice-versa to develop your film, you end up with the same images - same tone reproduction, film speed, granularity, sharpness. Same everything". So much for slavishly clinging to 68. Good enogh for me!

Steve Smith · Mar 27, 2007

Rick Jones said:
Richard J. Henry in his "Controls in Black & White Photography" questioned the claims by some that quality would suffer if all processing temperatures, including washing, were not tightly controlled.

I only ever control the temperature of the developer. Prewash, stop (water only) and fix are always made using the water from my cold tap regardless of what its temperature is and I have never had any problems.

Steve.

Pinholemaster · Mar 27, 2007

Reminds me of my old newspaper days. I work the late shift. No one would mix the d-76 before I got back. So I'd be on deadline with no developer.

Of course I'd mix the developer with hot water to make sure the powder would desolve properly. There I'd me with hot d-76 in a stainless steel developing tank putting the tank in the freezer for film storage to get the d-76 down to 68°F quickly.

The old days.

The fixer was always used at room temperature with no problems. My negatives from the 1970s are just as good today as the day they were developed.

noseoil · Mar 27, 2007

As has been mentioned, it is more important to be consistent with tempreature than stick to a specific temperature. The only case I can see a real importance in B&W developing is with a developer like rodinal. If you go over 68 with rodinal, you can expect to have larger grain than might be desirable with some films.

I try to keep fairly constant with developer, stop and fixer due to the Efke films I use. I have found that these softer emulsions can suffer from reticulation (meaning the emulsion can shrink and crack, due to large fluctuations in temperature). This is due to their older soft emulsions, newer film types like tri-x and fp4 don't have this problem as readily. tim

Ed Sukach · Mar 27, 2007

noseoil said:
.... The only case I can see a real importance in B&W developing is with a developer like rodinal. If you go over 68 with rodinal, you can expect to have larger grain than might be desirable with some films.

One problem exists in using chemistry at different temperatures - that of "reticulation". A sudden change in temperature between solutions can cause the emulsion to swell/ shrink, and the result is something like an "alligator skin" texture. I HAVE had that happen.

Re: Rodinal - This is not a developer that causes "large grain"... that, to me is a wide-spread MYTH. Back in the old days (sob!) there were a number of "miracle" additives to developers that promised miracles ... "Increase Film Speed by Ten Stops!!!" .. "Reduce Grain So That It Disappears!!!" They DID "work" - but at a terrible price to the rest of the quality characteristics of the film. Rodinal is an extremely "clean" developer - it DOES NOT increase grain; it DOES leave the appearance of grain exactly as it is in the film - well DEFINED, with no smearing between individual grains. There is a gain to this - ACUTANCE. Image boundaries appear sharp enough to slice a three-dollar steak. Some people go for "fine grain"; others are equally fanatic about sharpness - "acutance."

Michel Hardy-Vallée · Mar 27, 2007

The one temperature that has an important impact on your negative image is the developer. For the same developing time, a higher temperature will give you a higher contrast.

Theoretically, I suppose a cooler stop bath would stop more slowly and a cool fixer bath would fix more slowly, but even if that was the case to a significant extent, your image will LOOK the same, and that's what really matters.

Reticulation is also much less of a concern with modern films, and only second/third-tiers product are noticeably sensitive to temperature changes.

MattKing · Mar 27, 2007

The big advantage of 68F/20C is that it is so close to room temperature, so is therefore easily "repeated". Film and chemistry are designed to be used at that temperature, because it is easy to adjust them to that temperature and maintain them at that temperature.

They are also easy to remember .

If your working conditions are such that your room temperature is consistently higher or lower, and is reasonably close to 68F/20C, then it is fine to standardize at that higher or lower room temperature.

If you are likely to work in different locations, such as shared darkrooms, than 68F/20C is a good target, because most locations aim to be close to that temperature.

Have fun.

Matt

George Collier · Mar 27, 2007

I would vote with some of the above in terms of consistency of temperature not only between sessions, but of chemicals (and wash) during the process. There is a test cited in the thread indicating that this is not important, but I have read much to the contrary over many years. At some point I just decided to eliminate the variable and, using a stainless steel tank (as mentioned above), I bring every solution to 70F, +/- 2 degrees (small deviations I adjust the development time for), but every solution is within a 1/2 a degree on a given occasion, maintained with a water bath. This keeps the emulsion from swelling and contracting, keeping the grain pattern from becoming disrupted, and minimizing "clumping" of silver particles, at least that's the theory. The thought is also to minimize "wet time", or the total time the film is wet from development through wash. I may be overworking it, but it's a small addition to the total time in the darkroom, IMHO.

Roger Hicks · Mar 28, 2007

Ed Sukach said:
One problem exists in using chemistry at different temperatures - that of "reticulation". A sudden change in temperature between solutions can cause the emulsion to swell/ shrink, and the result is something like an "alligator skin" texture. I HAVE had that happen.

Dear Ed,

So have I but it's VERY unlikely nowadays. In fact it's hard to provoke even if you want it. The last popular film from a major manufacturer that was prone to it was the previous generation of Tri-X.

Nor do I agree about Rodinal. It's much better for some films than others, it's true, and it's also true that the finest grain and the best acutance are incompatible, but my own belief (in which I am not alone) is that there are many better grain/acutance compromises than Rodinal and most give more speed as well. The big advantages of Rodinal are that some people find it gives them excellent tonality, and it lasts forever.

Cheers,

R.

Ed Sukach · Mar 28, 2007

Roger Hicks said:
Dear Ed,

So have I but it's VERY unlikely nowadays. In fact it's hard to provoke even if you want it. The last popular film from a major manufacturer that was prone to it was the previous generation of Tri-X.

That very well may be. Thinking about it ... I haven't processed any film with great changes between solution temperature for quite a while; The last I've seen reticulation was probably with the "old" Tri-X. Wasn't someone here TRYING to get reticulation, without success?

Nor do I agree about Rodinal. It's much better for some films than others, it's true, and it's also true that the finest grain and the best acutance are incompatible, but my own belief (in which I am not alone) is that there are many better grain/acutance compromises than Rodinal and most give more speed as well. The big advantages of Rodinal are that some people find it gives them excellent tonality, and it lasts forever.

I agree with you disagreement (!!!). My point was not that "Rodinal is undeniably the absolute best", but that it was not a "Grain INCREASING" developer.

I happen to really, really like Rodinal - for its "look" (in which I am not alone, either). Its keeping qualities are an additional plus. Then again, I don't like cucumbers, or rhubarb ....
[/QUOTE]

Roger Hicks · Mar 28, 2007

Dear Ed,

Yes, I believe someone was trying without success to get reticulation.

Sorry for misunderstanding your point about Rodinal; the idea of a 'grain increasing' developer is indeed a bit weird, a bit like 'letting the cold in' (rather than the heat out).

Cheers,

R.

Peter Corrigan · Apr 4, 2007

I go with whatever temperature the developer (Mytol, in my case) happens to be, and simply adjust the times -- Ilford provides a time/temperature graph. Seems to work fine with Neopan 400, whether it is 18C or 26C. The other solutions will be pretty much at the same temperature, as they are all kept in the same room. I find it much easier to do this than trying to bring everything to a standard temperature. But it took me a while to become this relaxed about it!

Critical Temperature

Reticenti

JLP

David H. Bebbington

Rick Jones

Steve Smith

Pinholemaster

noseoil

Ed Sukach

Michel Hardy-Vallée

Membership Council

MattKing

Moderator

George Collier

Roger Hicks

Ed Sukach

Roger Hicks

Peter Corrigan

Critical Temperature

Membership Council

Moderator

Privacy & Transparency

Privacy & Transparency