[Leica] Dilution and developing to completion

[Mike Johnston <michaeljohnston@ameritech.net>]

> I agree. Whenever I have tried XTOL at 1:3 following Kodak's
> recommendations for Jobo's I get weak underdeveloped negs. I get much
> better results at 1:2 plis about 15% time with TMX or TMY.



Remember that there's such a thing as "developing to completion," meaning
that, if you chart development time against density with a particular set of
materials, the curve may flatten out or nearly so--meaning, additional time
*doesn't* add any appreciable density after a certain point. This happens
with many developers when you dilute them too much and it happens readily
with certain developers of weaker activity. It's common with Rodinal,
especially at higher dilutions, and it accounts for the fact that on the
'net you can see otherwise crazy-looking recommendations for Rodinal such as
"develop for 14-18 minutes" (it really can be about the same) or "I've found
I get the best results with Rodinal 1+100 if I develop for 28 minutes!"
(what they don't know is that developing for 14 minutes might yield
negatives that look the same) and so on. Often, effective film speed (EFS)
is tied to dilution, and you won't get the same speed point with one
dilution you do with another. Thus, the same film will be "faster" in 1+1
than it is in the same developer 1+3.

Incidentally, I usually write dilutions with a "+" because some people get
confused by the colon--they might think 1:3 means "one part developer out of
a total of 3 parts" (i.e., 1:2) rather than "one part developer to three
parts water." The plus sign simply makes it more unlikely that people will
make mistakes.

- --Mike