Loris,
Echague mentioned he used four
coatings in his Carbondir/ Fresson process.
So maybe the implication is like this:-
Maybe, not ! !
Base coat = hardened
gelatine.
Second coat = UN - hardened
gelatine.
Third coat = gelatine plus ? ? ?
Fourth coat = Pigment plus musilage ( ?
).
I have experimented with many combinations of
gelatine, gum arabic, poster paint (containing gum ), Sumi Ink, dry
pigment and found you can get acceptable results in several ways but
none about which I would be dogmatic to other
workers.
Words are only theory. One should do the actual work to really know what you
are talking about. I can only provide pointers and not cut and dried systems
full of detailed procedures.
Please ask about specific points as they come up in your experimenting. Hope
my postings have been encouraging.
Best, for now.
John - Photographist - London - UK