kallitype (was Satista)

Terry King ()
Sat, 18 January 1997 3:33 AM

Message text written by Judy Seigel
>-- I recall Peter Fredrick mentioning that
a no-pigment dichromate print turned green when he did something or other
to it. Was that 1% sulfuric acid? Anyone remember? Who has an intelligent
searcher? Shouldn't be difficult to find. (Maybe your water got acid....)

When you do this undercoat, though, Carlos, how do you register the
subsequent kallitype coat, unless you've pre-shrunk?
<

This is a point on which Peter 101522.2625@compuserve.com (F) and I disagreed. He did a series of
tests on the chrome staining of gum involving increasing exposure. I said
that if the exposure wassufficient to harden the gum for a print, and no
more, then staining did not appear.
I could not see the point of the tests.

As a test in my current Saturday workshop we are comparing the Judy method
with gelatine size, the 'pterotype' with dochromated but unpigmented gum,
and using ready sized papers that need no initialsize such as Bockingford
and Fabrano 5. The 'pterotype' got more exposure than it should have, a
more powerful and new lightsource, it acquired a greeny yellow stain.

Presumably the additional light causes the chrome salt to bond to the gum
so that it will not dissolve out as it will when sufficient but not
excessive is exposure is given.

As to the question of registration I cannot see why there should be any
problem.

The kallitype bases upon the straight Willis procedure has produced black
and brown prints. I will check to see if theacidity of the developer has an
effect but potassiunm oxalate was used for both.

Terry King

----------