You say:
"Whatever, your "explanation" above is contrary to my understanding and
experience. First of all, I have never seen *any* gelatine "gel" on the
surface, except in a cold room in winter, say, below 65 degrees F."
It's colder than here now at noon on the day after mid-summers day.
" But if I were deliberately trying to get gelatine to gel on the surface in
summertime, the best way to do that would be to dry it rapidly with heat
-- tho I doubt I could anyway. "
In practice it works as I reported.
In my tests with Knox (about 200 bloom, I'm told), 300 bloom pigskin and
the 260 bloom ossein, BTW, *all* sink nicely into the paper when applied
warm (about 100 to 120 F) in a warm room (75F).
If I lived in Santa Fe my method of making gum prints would be very different
from that I employ in Twickenham. I can only suggest that as it is colder and
more humid here gelatine is likely to gel on the surface more easily, piu
facilemente ma non in Firenze Riccardo?
"Nor am I convinced that gelatine on surface "dissolves" faster than when
sunk into paper, tho I suppose it could float off -- but that would have
to be some gob of gelatine... "
Well it does !
> Purified water is what pharmacists use. It has the impurities removed by
reverse
> osmosis rather than by distillation. It tends to be sustantially cheaper
> especially from health food shops. The purified water is of course not
intended
> for gum but 'solution' processes such as salt, kallitype and platinum.
"We pay about a dollar a gallon for distilled water in the supermarket..."
Somebody has cornered the market in water here.
Terry