"For making transparencies on glass, use a gelatine mixture: 50 gm gelatine
to 1000cc water. Rinse the gelatine once or twice with water [don't bother
with modern, good quality gelatine], stand it aside for an hour or so, then
dissolve in the water (by warming the two on a water-bath), and filter hot
through cotton [again don't bother]. Warm the solution to about 130 degrees
F [about 55C] and pour over the plates. Place them on a cold horizontal slab
to cool, and as soon as set, dry, preferably in a drying oven [just keep the
dust off]. Immerse the plates for about five minutes in the sensitizing
solution and dry in the dark. Print in the usually way but far deeper than
for a paper print."
Please let us know how you get on.
Philip Jackson
pjackson@nla.gov.au