Re: yellow gelatin

Judy,
     the old glyoxal is concentrated urine yellow, the gelatin is Knox, and
when I mix the glyoxal in the gelatin (25ml tho) it is definitely yellow.
However, I bet the alkaline thing is operative, because I gum printed with
well water always until moving down here, and I know I have a supersensitive
nose, but I can smell chlorine when the city water comes out of my faucets.
I have a pH meter and I can't find it (amazing that that is the case, since
I have all gum stuff in one measely room) but I'll have to measure my water.
     However, I remember my glyoxal being clearer. There's no way it would
become contaminated with anything because I carefully measure out amounts
with a test tube, never putting anything into the bottle. Bostick and
Sullivan glyoxal.
     But as I said, it works fine and doesn't seem to yellow the paper any
amount that would be noticeable or obnoxious.
     Yes, I came across some mentions of using a warm coating to "warm up" a
gum print...that'd be the last thing I would consider doing! If I wanted
that I could just let the dichromates build up in the print.
      Speaking of dichromate buildup, I remember Sil saying there was no
need to wash residual dichromate out of the print--it would not damage its
archivalness. With the lower dilution dichromate this is no longer much of
a problem for me, but I want to make sure that this is the case, that
dichromates do not "age" in a print, if left behind in trace amounts? I was
getting a batch of prints ready to frame and I ended up clearing them just
to be sure they were completely archival because I didn't want to chance it.
What do you all think?
Chris
----- Original Message -----
From: "Judy Seigel" <jseigel@panix.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Tuesday, March 23, 2004 4:46 AM
Subject: yellow gelatin

>
> On Mon, 22 Mar 2004, Christina Z. Anderson wrote:
> >
> > Now this is interesting. So what I deduce from this is glyoxal yellows
with
> > age. However, it worked great still with the 40 sheets I sized before
this
> > batch, and there is no sign of yellowing on the paper to any degree. So
> > maybe this isn't a biggie.
> > Chris
>
>
> Christina, my old stock glyoxal tends to look yellow, but it doesn't look
> yellow in the working solution-- which is after all only 15 cc/liter.
> However that working solution turns VERY yellow or orange when you put an
> alkali in it -- as is recommended for uplinking. I tried all the alkalis
> & found one that didn't yellow it so much-- I think it was bicarb... but
> then I gave it up, deciding my gelatin is linked enough.
>
> And, as I've mentioned, it doesn't turn yellow when I rinse it after the
> hardening bath. But maybe your *gelatin* had some alkali in it. What
> kind was it?
>
> PS. and to think that the Pictorialists added a special coat with orange
> and other colors to give a golden/yellow *tone* to the paper !
>
> Judy
>
Received on Tue Mar 23 08:01:59 2004