B+W film developer

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Hi, I have some questions about B+Wfilm developer. It may sound funny to you, but I appreciate if you could give me some advices. What is the advantage of using diluted developer besides changing a lenght of developing process. I know many people hate to use developer straight, but I don't know why? Let's say, here is two films which have been exposed exactly same and shot same scene. (same ASA) And If you process those film (by adjusting the process time) to get exactly same contrast index using same developer but different dilution, one is stock and the other is 1:1, would you see the difference in final prints from those negs. Or, they are different such as grain, separation, etc... even though they have same CI.

Also, some people say processing in a higher tempture makes grain larger. Does it mean processing in a lower tempture makes grain smaller? How about if their CI are same? For example, according to Kodak, in a T-Max 100 and D-76 combination both 6 1/2min @68 degree and 5min @75 degree should produce almost same density. Do you think they look identically same in final prints or should there be obvious differences in the quality? Please explain in the beginner's term. Thanks Max

-- Max (rjjr23@aol.com), September 25, 2001


Max, All good questions, and they probably require too detailed answers to really address completely here. Your curiosity is laudable and I would recommend you take a look at some authoritative texts on the subject. The Negative by Ansel Adams and The Darkroom Cookbook by Steve Anchell would contain the info you need. (Amazon.com or Amazon.de or whatever country you are from should have these available)

At any rate, here are the short answers to your questions. 1)With most general-purpose developers (D-76 type) there is a difference in silver solvent activity from the sodium sulfite at different dilutions. This means "finer" grain and less sharpness straight than at higher dilutions. 2) Grain can be affected by temperature shocks and bad handling of the film, but the diffence between processing at 20 degrees Celsius and 24 degrees Celsius is neglegible. Kodak recommends higher temperatures for some films.

If you are just beginning, the best advice I can give you is read, read, read. Hope this helps,


-- Doremus Scudder (ScudderLandreth@compuserve.com), September 25, 2001.

The higher the development temperature, the greater the tendency for grain clumping (what we perceive as increased grain). 20 C is about the practical lower limit where clumping no longer occurs due to temperature. Since grain clumping can also be affected by increased time in the developer, it usually makes no sense to develop below 20 C. Many modern films (especially T-Grain films) are much less susceptible to grain clumping due to temperature up to about 24 C. But if I were developing Tri-X I would not go over 21 C.

Many developers exhibit "compensating effects" in higher dilutions. The compensating effect results in less development of the highlights with low to moderate agitation. You can probably get the same or similar effect with less development time and using an undiluted developer, but it becomes difficult to control accurately at the shorter development times, and even slight variations in agitation become much more critical.

The dilution effect on grain depends on the developer. As stated by Doremus above, solvent developers, such as those that contain sodium sulfite (D-76, etc.), have a lower solvent effect at higher dilutions. Solvent effects reduce apparent grain but also reduce sharpness. Non-solvent developers such as Rodinal show less grain at higher dilutions (in addition to less contrast). This is because the Rodinal is a high alkaline developer and alkalinity has a tendency to produce grain clumping.

-- Michael Feldman (mfeldman@qwest.net), September 25, 2001.

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