Re: need advice on gum coating

Charles, Judy, Dave, Kate, et al,
     I agree with all said (so that must make it gospel--just kidding!), and
I bet your coating is too thick, or that you are continuing to brush too
long. The brushing should be completed quickly within maybe 45 seconds or
else you'll streak it, but even if you do, it doesn't much appear in the
print in areas of detail. Skies are another story, but as Dave says, so
what--it adds to the character.

     Judy, I must revisit the foam applicator...I found it abraded the
paper, aside from the fact that it put my teeth on edge with its noise and
"drag". But after your description, below, I think I'll give it another go.

     As one "old book" says, if the coating streaks, it is either too thick
or too thin--the latter, when if follows the brush in "waves", the former
when it stands in ridges. When my coat goes on even it initially streaks
and then spreads out evenly without touching. Otherwise I must coax it
along as in the flick flick technique described below.
Chris
----- Original Message -----
From: "Judy Seigel" <jseigel@panix.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Saturday, February 14, 2004 11:48 PM
Subject: Re: need advice on gum coating

>
> 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
> critical...
>
> 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.
>
> Judy
>
Received on Sun Feb 15 08:49:49 2004