Originally Posted by
interneg
Very little of that's likely to be the pyro. Of either sort. The useful pyro effects seem to be largely restricted to emulsion tanning in unhardened emulsions.
It seems (from the available industry literature - at the engineering/ research/ academic level - not the relatively popular market books that come to a halt in disclosable knowledge somewhere between 1950/1960) that in those developers, it's largely Metol exhaustion effects or Phenidone byproducts causing development inhibition that produces the observable edge effects. Adding an effective source of electron replenishment (e.g. HQ/ AA/ HQMS etc - and this seems to work even outside conditions that might be characterised as 'superadditive' - even though superadditivity is not as clear-cut as home-brewers assume once any emulsion addenda come into play) will largely switch off the effect in MQ developers, but can be exploited in PQ type developers to produce radically differing levels of the effect. If you strip out the pyrogallol from various staining developers what you're largely left with are bowdlerised Beutler (which produces high sharpness both microdensitometrically and perceptually) derivatives - or accidentally functional PQ relationships - and that one of the isomers of HQ seems to behave sufficiently like it in specific formulae, just producing a slightly different dye. The research wasn't purely microdensitometric, it involved large quantities of double blind print testing - which found that adjacency effects had to be balanced against granularity - and that extremely strong adjacency effect producing developers (POTA) could produce markedly unpleasant prints. By using non-solvent developers the ability to access the Bromide & Iodide placed in the emulsions to produce sharpness enhancing adjacency effects through development inhibition is left unused as well - and it is in accessing the Br and I that D-76 and ID-11 are able to deliver remarkably sharp results - if basic process controls are instigated. The other aspect that is often ignored is that a pH of around 10 seems to maximise sharpness. If you put all these together, you can zero in on potential candidate developers. In other words, an appropriate ratio of P:Q (or AA etc), some solvency and carbonate buffered to just under a pH of 10.
From microdensitometric study we also know that the visually perceivable effects of anything more than nil agitation effectively boil down to differences in overall contrast with no meaningful impact on sharpness measurable or perceivable (when the experiments are properly controlled) - with possible exceptions for litho film in litho developer in specific situations. In other words all that is happening is that the developers you are using & how you are using them is probably widening your margin of error against overdevelopment for the grade you want to print on and possibly underexposure. I've had enough staining developer outcomes through my hands to feel that it's pretty obvious to me why the manufacturers with large basic research capacity, never mind significant organic chemical synthesis resources, seem to have stopped research on staining developers a long time ago. DIR/ DIAR couplers (and research into how to potentially get similar effects from regular B&W emulsions through new emulsion making approaches) were able to deliver effects that many assume their magical-developer-recipe-silver-bullet is delivering (even though it isn't).
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