From: Judy Seigel (jseigel@panix.com)
Date: 03/08/03-10:13:02 PM Z
On Sat, 8 Mar 2003, Christina Z. Anderson wrote:
Oh my gosh ---
My Kremer catalog lists "genuine pieces' of Polish amber, $13.50 for 11 g,
tho I doubt this is that amber... Even if, I think mixing chloroform and
ether would be -- uh oh, bring out the safety police -- probably WORSE
than aqua regia !!! But I'm sure you sent that just for fun, I'm sure...
The vernis soehnee sounds about like Demachy's description -- we figured
it was some form of shellac. Maybe the method of mixing here described is
important... My mix didn't do on modern gelatin sized paper what he said.
However and anyway, presumably we have here the holy grail at last....
(does anyone know what the holy grail was supposed to do?) And we can
probably not quite fully fathom the exciting life of early photographers.
(Have you read Cyanide and Spirits?)
Meanwhile, thanks Chris. you are a genius. I'll let you know what happens.
Judy
>
> The amber varnish is thus prepared. A quantity of yellow amber, broken into
> small pieces, is placed in a bottle so as to occupy about three-fourths of
> its capacity. A mixture of equal parts of chloroform and ether is now poured
> into the bottle, in such a quantity that the amber is hardly covered. After
> some few days the liquid contents of the bottle are poured upon a filter,
> and the pale yellow liquid which passes through is amber varnish.
>
> The solid fragments of amber are allowed to remain in the bottle, to which
> can be again added the mixture of chloroform and ether, and a fresh quantity
> of varnish obtained. The same amber will serve for a dozen or more times,
> it' care be taken to keep the bottle well closed.
>
> To prepare the gum-lac, or Soehnee varnish, place in a bottle-
> Gum-lac White 2½ ounces.
> Alcohol 35 ounces.
>
> The bottle is now well stopped and left several days, being well agitated at
> frequent intervals; the liquid is then left to settle as much as possible,
> the clear portion poured off, and the remainder filtered. The whole of the
> liquid can be filtered; but it is not recommended, as it passes very slowly
> through the paper. The colour of this varnish is of a pale yellow, less deep
> than the chloroform.
>
> Instead of making this preparation in a bottle at the ordinary temperature,
> it will be found a more expeditious plan to employ a flask (containing the
> materials), placed in hot water. If the flask, thus kept heated, be agitated
> from time to time, the gum-lac can be dissolved in about halt an hour. There
> is always a whitish deposit, which does not dissolve either in cold or hot
> alcohol; this must be allowed to perfectly settle before the varnish is
> poured off for use.
>
> The amber varnish is very easily applied; the collodion surface of the
> plate, on which the picture is formed, is covered with it in the same way as
> the collodion was applied, the excess of liquid being received in the
> bottle. In a few seconds this varnish is dry. It is well, however, to expose
> the plate for an hour to the sun before being used for printing from.
>
> It is more difficult to make use of the white gum-lac varnish, because the
> plate then requires to be warmed. For this purpose it is carefully exposed
> to the flame of a spirit lamp, or before a clear fire, taking care that the
> heat is equally applied by moving about the glass plate at some distance
> from the fire, or above the flame, it' this be employed.
>
> The temperature of the glass should be such that, when applied to the back
> of the hand, it can be borne without inconvenience. If too hot, the, varnish
> flows. with difficulty over the surface; and if too cold, it does not dry
> sufficiently quick, and becomes chilled or partially opaque. This varnish is
> applied like collodion, the excess being received in the bottle, and when
> the surface appears dry, the heat is continued a short time longer, so as to
> cause a proper transparency and adhesion of the coating.
>
> It is especially difficult to use the gum-lac varnish for plates of large
> size, for which, all things considered, it is generally best to employ the
> amber varnish. The negatives are less firmly varnished, and, in consequence,
> not able to yield so large a number of proofs; but, on the other hand, it is
> much more easily applied."
>
>
>
>
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