From: Ken Watson (watsok@frii.com)
Date: 03/05/03-03:10:25 PM Z
Most varnishes have a few common components. A solvent, the dissolved
material " varnish" , and an added substance that allows the material to be
somewhat flexible after the solvent has dried to prevent cracking. Alcohol
is a common solvent for may things, including early furniture varnishes.
Glycerin and castor oil you mention below are most likely what gives the
film it's flexibility. Lavender oil has also been used in the past...I
suspect corn oil, peanut oil or other oils would work similarly. Today we
can see that the early formulations have tended to darken over time.
>
> Christina Z. Anderson wrote:
> > 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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