From: Christina Z. Anderson (zphoto@montana.net)
Date: 03/05/03-01:27:17 PM Z
Dear list,
What is transparent celluloid?? I have seen a number of formulae that
have that as an ingredient for varnish.
I finished researching thru Anderson's book, and have been on this
"quest" since Judy mentioned vernis soehnee, and asked what Robert
Parke-Harrison uses to varnish his prints, to find what might have been a
varnish used at the time that product (vernis) was used. Interestingly,
Anderson lists these ideas, below.
First, I had come across a detail in one source that an acrylic gloss
medium diluted 1:6 would raise the dmax of platinum. So I coated that onto a
cyano, a platinum, and a gum. No change in gum, the cyano actually lowered
in dmax, but the platinum did get darker (all prints done half varnished,
half not, looking for line of demarcation).
Now, here's what Anderson says, in relation to (shock) varnishing
platinum--who knows how archival, and of course those of you perfect
platinum printers probably wonder why anyone would resort to these ideas
with a print that costs $7 for an 8x10 by my calculations, or even shine up
a print in the first place, but:
1. French picture varnish diluted with alcohol (?) (still available?)
2. Johnson or Old English Floor Wax (!), brushed on with a stiff brush and
then polished with a rag (anyone have some of this and can tell me what is
in it? Or I'll just have to make a trip to the grocery store...)
3. Butcher's Boston Polish (slight pink cast) (still available?)
4. 3% gelatin solution.
Neblette's is:
transparent celluloid 1 oz.
castor oil 1/8 oz.
amyl acetate 16 oz.
methyl alcohol 4 oz.
Immerse dry print for one minute, then drain, hang, and dry.
or
borax 30g
glycerin 30ml
shellac 70gm
water 1000ml
boil for 1/2 hr and add
methyl alcohol 250ml
Immerse in this as above.
Another point: Anderson talked about the line of demarcation thing!
He said this: if you use a not hot developer with platinum, and immerse the
print unevenly, the line of demarcation is not a prob because it is a
develop to completion process. BUT, if you use a HOT developer, it IS a
problem, and you must immerse all at once. THAT makes sense to me, maybe
insofar as the temp that varies as the developer cools rapidly in the tray
would affect the development. This may also explain why some have this
problem, some don't sometimes it happens, sometimes it doesn't. FWIW.
And, re: gum, Anderson mentioned adding an alkali to the water to force
development of an overexposed print, 1 tsp per 32 oz of ammonia, sodium
carbonate, or bisodium carbonate. He also says he has developed stubborn
prints for up to 48 hr, and that values may be lightened to an almost
unlimited extent. So there's hope for those throwaways.
And that sodium dichromate, which he prefers, at max solution (96%) in
comparison with potassium di at maximum solution 10.5%) is 4 times the
speed. It is available thru Artcraft chems I noticed.
Over and out...
Chris
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