Quote Originally Posted by Mark J View Post
I'm with Drew on this.
I don't think you've done the baseline work on what HP5+ is capable of in staining developers.
Sorry Mark, but the two main staining developers are respectively a muddled variant on Beutler and a D-76 derivative modified to stain. Most of the effects attributed to the 'stain' (really just a not very good coupler forming) have more to do with the effects of the other developing ingredients (which were known in manufacturing R&D long before anyone was trying to revive staining developers). The overall impact is that some of those development inhibition effects contribute to improved sharpness and more controlled highlight density - and for somewhat related reasons, also dramatically increase the error margin for coping with poor process control. Having observed multiple users of staining developers over the years, a significant majority of them are not (or will not) enact the basic process controls that are implicitly assumed by Ilford, Kodak etc's instructions - and thence they attribute the relative improvement of their negs to some 'magic' in the developer rather than it being far more insensitive to significant user error (owing to development agent exhaustion effects, inhibition effects, relatively low/ slow development rates etc). For what it's worth, most of the big manufacturers' developers commercialised since the mid-late 1980s have set out to exploit development inhibition effects properly (i.e. developing agents properly balanced against solvency - emulsion interaction is essential for grain/ sharpness relationships - which staining developers are inherently unable to do owing to non-solvency - and non aqueous developers like HC-110 struggle with). Very simply, if staining developers had effects that were truly uniquely effective, the big manufacturers would have made them decades ago (and probably made them safer) - given that it is known that Ilford, Kodak etc have been willing to use pretty unusual ingredients (or custom synthesise those that they need) in mainstream developers, the claims around stain owe more to the journalistic abilities of their promoters than anything else.