>
> 1. What sort of ranges are we talking about here ?
>
> 2. Surely the disadvantage of the stain is that it flattens the negative.
>
> In my experience a good clean Pt/Pd negative, for a full range of tones,
> should have a density range of around 2.0, maybe a little higher. The best
> developer, out of a bottle, for that range is PQ, and, for home brews. acid
> amidol.
>
The pyro stain *increases contrast* for Pt/Pd printing or other UV
sensitive emulsions because the stain, which is proportional to silver
density, increases the effective density of the highlights when printing
by UV light. My recent first test of PMK pyro using HP5+ gave me a much
higher effective contrast than any standard development of that film has
done, giving adequate contrast for a Ziatype with no contrasting agent.
That is equivalent to a range of about 1.9 or 2.0 printing from negs
souped in "regular" non-staining developers. I'm not sure how the stain
density will affect densitometer readings, and haven't a densitometer
handy right now to check. But it prints in platinum like a 2.0 neg. I
haven't yet had a chance to see whether it will also print at a much
lower contrast on standard silver paper, but it looks promising just
eyeballing the negs.---Carl