Interesting. It is generally assumed (or stated/claimed) low-sulfite Pyrogallol/Catechol B&W film developers simlutaneously tan and stain imagewise. Tanning and staining actions are typically thought of as essentially one "process".
Originally Posted by Photo Engineer
So, concerning these developers, is it generally fair to say the sharpness typically associated with them has mostly to do with edge effects and more pronounced graininess (relative to a typical solvent developer)? It would seem resolution and traditional acutance would at best be no better than a general purpose developer - in fact may be worse due to dye spread.
Further to this, with well hardened film, if tanning effects are limited, is dye spreading or image smear also limited? Or do we just get dye spreading without enhanced edge effects?
It is interesting that sulfite can reduce image smear. Would this be an effective argument for finding a balance between maximum imagewise stain and image precision when formulating a staining developer? I don't get the sense that is the usual approach. Most formulations seem to be aimed at using the lowest practical amount of sulfite possible to stabilize the formula, in an effort to maximize imagewise stain.
Last edited by Michael R 1974; 06-19-2013 at 04:17 PM. Click to view previous post history.