Quote Originally Posted by Rudeofus View Post
I would like to learn why this recipe did what it did. It looks very similar to PC glycol in composition but adds sulfite and uses more phenidone/ascorbate, two things which I would expect to cause higher contrast and small grain. Did you develop this formulation yourself or did you get it from somewhere else?
For reference, the formula is here: http://www.apug.org/forums/viewpost.php?p=1285367

This developer has a relatively low alkali/phenidone ratio. I suspect that this results in poor buffering compared to the activity of the phenidone, causing a high degree of compensation -- suppression of highlight development -- which reduces contrast. It also has a low ascorbic/phenidone ratio of only 18, whereas this is >= 40 for most PC developers. This ratio is 0 for ultra-low contrast POTA, so it makes sense that contrast will drop as the ascorbic/phenidone ratio drops. However, I suspect that poor buffering is mostly responsible for the low contrast.

You could say that I invented this myself, but the truth is I encountered it by accident. I was trying to create a concentrate-version of PC-Sulfite, and not all of the ascorbic acid would dissolve in the propylene glycol. So I added some sodium metaborate to assist dissolution. That forced the sulfite-level to be much lower (35 vs 90 g/L) to keep pH=8.2. That loss of alkali in turn hurt buffering, which (I suspect) reduced contrast.

If you want to reduce contrast even more, I suggest multiplying the quantities of all components except phenidone by a factor less than 1.0, and increasing dev-time. This will multiply both ratios by your factor, which I believe will increase compensation.

BTW, have you tried Diafine? I've read that (1) it has good compensation because it's a divided developer, and (2) it pushes Tri-X well.

Mark Overton