> 1 package of Knox gelatine is indeed 7 grams. Do you remember that you were
> using one package per 100 ml? If you still have the note around, I would
> appreciate it if you could check it some time at your convenience.
I finally am getting around to checking my notes. The recipe I used was:
1 package of Knox unflavored gelatin (7 g)
100 ml water
1 Teaspoon sugar
Ivory Black Gouache (Winsor Newton) a roughly 2 inch line of pigment
squeezed from the tube.
This was mixed and coated on a piece of heavy callibgraphy paper and an
overhead projector slide according to instructions given to me by Sandy
King. The gelatin did not stick to the platic substrate.
I compared the results to a snippet of Hanfstaengl tissue that was sent to
me by Arthur Krammer. The film thickness for the Hanfstaengl paper was
close to 0.002 inches, and my homemade tissue around 0.0025 inches. The
homemade tissue was noticeably more soluble in warm water than the
Hanfstaengl. This could be due to differences in the hardness of the
gelatin used, and the age of the tissue.
I tried printing with both tissues, and had much better luck with
the homemade stuff. However, since the Hanfstaengl was tried first, and
was my first ever attempt at carbon printing it probably isn't surprising
that I din't get an image with it. My second try with the homemade
tissue gave me a nice little 35mm contact print. Both tissues were
sensitized using 3% Potassium Dichromate, and exposure was to bright
sunlight. For my first exposure, I tried 2 minutes which was obviously
too much. The second try used a 1 minute exposure. I also tried a 2
minute exposure on my homemade light table, but this was obviously
underexposed.
Hope this helps a little.
- Wayde
(allen@boulder.nist.gov)