Re: need advice on gum coating

From: Judy Seigel ^lt;>
Date: 02/14/04-10:48:03 PM Z
Message-id: <>

On Sat, 14 Feb 2004, ryberg wrote:

> I've read most of the modern books on gum and several of the old ones.
> I can't get any where near an even coating--I get brush marks and uneven

Charles, I agree with most of what's been said -- but I also find that
most of the "modern books on gum" leave out something I've found

You don't say what size you're working, or on what paper, but especially
for a larger size (11x14 or more) it's tough to cover evenly if your
emulsion is too thick -- some folks use sensitizer 2 parts to gum 1 part,
which is a pretty good consistency, but since I don't like using that much
sensitizer, I just add water... that is (roughly) 1 part gum, up to 1
part water, 1 part 26% am di.

That's of course, assuming your sizing is even... if you're gelatin
sizing with a brush, all kinds of things can happen, especially if the
paper folds onto itself... Vat sizing with squeegee is much more likely
to be even (assuming you add that defoamer, so you don't get bubbles).

But if you're seeing "brush marks" in the coat... you shouldn't, because
the coat is best applied (IME) with a foam applicator -- get a wet layer
over the area as fast as your hand can move, don't think about even, just
lay it on -- THEN you go over it with a dry hake brush -- flick flick
flick very lightly and rapidly one way, then the other. If you've gotten
the paper too wet, you may have to change to a dry hake brush in progress,
but otherwise just quickly tamping it on a paper towel partway will do.

This *burnishing* of the coat leaves it quite amazingly even... tho like
folks say, don't expect it to look like a perfect sheet of formica.

Received on Sat Feb 14 22:48:18 2004

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