First of all: I have no direct experience with pyrocat-HD itself,
but had some with a few catechol-based developers and other
staining developers, like tanol, finol, and Thornton's dixactol.
I guess none of those are in a different ballpark if not very
close brothers; even some claimed to be the same formulation under
a different name.
My experience on staining (either catechol or pyro) is :
- Catechol stain is faint.
- Different emulsions colors differently, with several degrees of
intensity, no matter what kind of agitation you use.
- Most stain color seems to be washed out during fixing and
washing.
I've found that the advice of using an alkaline sodium
thiosulfate-based fixer (as TF2) without sodium sulfite keeps as
much stain as you will get. I doesn't keep beyond the day, so I do
prepare it just before use. I don't know the chemistry behind
that, it's only a empirical observation after following advice.
- Without carriyng proper testing which needs more equipment and
methods than most of us have, it's almost impossible to tell
apart what is stain by reduction and what is gelatin toning
(inside the picture, of course).
As final note, my lab gets water in a wide range of temperatures
depending the season, so I standarized in 24C processing (75F), as
it's easier to heat in winter than cool down during the long
summer. It may take its role in staining, can't tell as I'm using
this temperature as standard for a very long time.
my 2c.
On Sunday, February 07 2021, 23:01:22, Tim Daneliuk wrote:
Tri-X (at least TXT - how many versions of Tri-X have there been?
Many, methinks.) stains most.
Neither APX 100 or FP4+ stain anywhere near as much.
