RE: Sizing paper with gelatin

On Mon, 26 Dec 2005, Loris Medici wrote:

> I plan to use 6% gelatine solution and a separate hardening bath. If it
> can be made without having a messy & hard to coat gelatine solution, I
> would like to learn the way of sizing the paper with gelatine +
> formaldehyde in one step.

Loris, my tests with % gelatin solutions showed 6% is too heavy -- it
doesn't give a good gradation. However the bloom of the gelatin is
another variable -- the food gelatin we use (Knox) is, if memory serves,
200 lb bloom. I tested 300 lb & something or other else, none of which
gave the scale of the food gelatin.

Again, my tests (and I'm NOt the only one -- happened to come across some
notes from Ernestine Ruben yesterday, saying the same thing) show that a
BATH in gelatin with light squeegee afterward (illustrated P-F #9) gives a
much better coat, in ease of handling the paper, durability, evenness and
just general feel. I suppose brush size is less trouble initially, but so
is 1-hour photo.

Another test, while you've got your 21 steps out, is with hardener in or
as separate bath. That's one I never tested, and I so dislike the idea of
hardener in the gelatin I'm not sure I could be my usual objective self,
but it does waste gelatin since only good for a day. I size a big batch &
find, contrary to received wisdom, the paper keeps.

And a PS to Kate getting pigment stain on -- was it Montvale? Is it
possible something else could have gone wrong with this batch? A new
source of paint, or gelatin or something else in the cookery? I've tried
some pretty evil papers (including, I think, Montvale about 20 years ago,
which is no proof of anything since they change them without our
permission) and do not recall one that when properly sized still pigment
stained.

I'd suggest just giving another coat of size and (separate !!!) hardening
bath. I've also found that a fresh size on top of a destroyed size (say,
from being cooked, or too weak, or from rotted gelatin) restores it.

PS.I changed the subject line from "sizing with gum and dichromate" -- I
will say, however, I still have no idea why one would want to do that.

Judy
Received on Tue Dec 27 12:34:40 2005