Sandy, do you think the change in A & B parts is affecting the development densities at differing tonal ranges in some of the above posts, or is it more a matter of dilutions and agitations? I understand why you have altered the A & B ratios for stain. tim
Originally Posted by noseoil
The slight increase in the amount of A solution serves to reduce oxidation, which in turn lowers B+F stain. Probably not significant if you are printing with silver processes.
That's what I do. I've just been calling it something else. Interesting that your dilution is just about what I have been using.
Originally Posted by sanking
Do you vary the solution A to B ratio to yield greater contrast or to provide compensating development in extremely high SBR situations?
Originally Posted by c6h6o3
The primary reason that I vary the A to B ratio is to reduce B+F stain. Since I work with alternative processes my development times are much longer than for silver. Longer development times with any pryo developer results in greater oxidation and general stain. Increasing the amount of A relative to B reduces oxidation.
As I mentioned earlier, this probably is not of any importance if you develop for silver printing, since development times are much shorter.
Ordinarily I test for SBR with BTZS testing and adjust for subject brightness by varying the time of development rather than changing the dilution. However, there are times, say with extreme SBR conditions of -10 or more, when varyying the dilution may work better than a change in temperature.