Re: Gum Stain


Judy Seigel (jseigel@panix.com)
Sun, 28 Nov 1999 02:11:34 -0500 (EST)


On Sat, 27 Nov 1999, Joao Ribeiro wrote:
> > which will make a harder emulsion, and/or
> > exposing longer. Each mix is different, so it's hard to generalize, but my
> > feeling is that a longer exposure will come to the same point of
> > development without staining if you develop longer.
>
> So I should make the hole print harder (speaking about the gum physical state)
> and develop longer, is that it?

It's so hard to tell this in advance (for myself, let alone another
person!), but generally speaking a 1 to 1 emulsion is pretty soft. Of
course you can, as Dave says, make it harder by exposing longer, but as
noted that can cause its own problems -- and very long development may be
another big pain in the neck... Why not try 1 part gum to 1-1/2 parts
sensitizer with everything else the same and see if that takes you in the
right direction.

I'll add that when I learned gum, the standard emulsion we were told to
begin with was 1 part gum, 2 parts dichromate -- we only changed it if we
wanted more contrast, and went to 1 to 1. Then I got in the habit of 1 to
1 on the theory that it put half as much dichromate in the environment,
but oh dear, I think the polar ice cap is going to melt and drown us well
before the dichromate kills the fish in the sea.

best,

Judy

>
> > The other point is that if it's just a one-coat gum, some *light* staining
> > is not only acceptable, but often attractive. Sarah Van Keuren and I
> > discuss this issue in PF #3, by the way...
>
> I'll read it again, ThanksJoao
>
>



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