From: Christina Z. Anderson (zphoto@montana.net)
Date: 06/15/03-10:03:10 AM Z
Ha, believe me, Keith, if it is sour you know as SOON as you open the cap.
It is really stinky, like sour milk only worse. Actually, it smells like
rotten eggs. This only happened with the gum I mixed myself with no
preservative and with powdered pigment and soured within a couple weeks if
not a week. Ph Formulary's Bud said it sours immediately, within a day or
two, and he may even be right. It still works just fine, it seems to be a
bit thinner in consistency and I would assume the greater acidity would
increase the speed of the gum to an extent, kind of like adding lemon juice
as they used to do, but I have not done anything different in practice with
it. Except plug my nose. Frugality won't let me just toss the stuff down
the drain, but believe me, I am awaiting the day when I use it all up! The
next batches I mixed I added sodium benzoate to and they are just fine. My
gum from 5 years ago is also just fine--from Daniel Smith. No souring
there.
Chris
----- Original Message -----
From: "Keith Gerling" <keithgerling@att.net>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Sunday, June 15, 2003 10:24 AM
Subject: RE: a newbie's first post: gum, temperaprint, oil printing,
sizing,and computer negatives
> No, it doesn't smell. But I've been storing it in bright sunlight. Not a
> good idea, I guess. I just noticed a warning on the label: "Pure gum
arabic
> has a limited shelf life. Do not use after six months from purchase". I
> guess I had better get busy...
>
> -----Original Message-----
> From: Katharine Thayer [mailto:kthayer@pacifier.com]
> Sent: Saturday, June 14, 2003 6:17 AM
> To: alt-photo-process-l@sask.usask.ca
> Subject: Re: a newbie's first post: gum, temperaprint, oil printing,
> sizing,and computer negatives
>
>
> Hi Keith,
> Does it smell funny? If not, it's probably not actually souring. As a
> general rule, gum that is purchased in a liquid form contains a
> preservative (although it's also generally not specified that that's the
> case) and should keep for months without souring, if not years. I
> suppose the longest it's ever taken me to use a jug of gum was two
> years; there was no souring in that time. In my experience, liquid gum
> does darken with exposure to light; for that reason I keep my gum jug
> covered with black plastic to keep the gum light and clear. The
> darkening of the gum doesn't change its functional properties, but since
> I mix colors by eye rather than by weight, it's important to me to work
> with clear gum that allows me to see the colors accurately when
> mixing.
> Katharine
>
> Keith Gerling wrote:
> >
> > On Fri, 13 Jun 2003, Judy wrote:
> > > There's
> > >also the fact that we don't know what the hell Demachy was using for
gum.
> > >He probably mixed it himself, it may have been sour, which changes its
> > >behavior
> >
> > How does being sour change its behavior? I recently purchased a gallon
> of
> > 100% pure gum. 14 baume. It was crystal clear when I opened it last
> week,
> > but now its turning yellow and I suspect its beginning to "sour". Still
> > working fine now, but what should I expect?
> >
> > Keith
> >
> > website: http://www.gumphoto.com
>
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