The actual image quality has to wait until I print a lot out of the negs, but I'm a bit convinced that ascorbate is actually involved in the image formation in this formula.(posted 8324 days ago)I remember HP5+ (and TMX) exhibited brownish tone in XTOL 1+1, and this is also clearly seen with the rolls I processed so far. I also pulled an APX100 neg processed in XTOL 1+1 which was black black. A roll of APX100 processed in D-76Ad 1+1 is also black black. In Microphen, D-76, HC-110, HP5+ were more black than XTOL or D-76Ad. As far as the colors of the negative images are concerned, D-76Ad is closer to XTOL than D-76d. This is presumably a projection of grain structure, many say the finer the grain the warmer the tone, but I'm not sure if it's that simple.
The pH of D-76Ad is higher than D-23/25 type formulae. So low pH is not the case. Sulfite concentration is the same. At this point my best guess is that that vitamin is doing something.