[alt-photo] Re: evaporation of gum mixture

Sat Jul 3 14:46:47 GMT 2010

I keep gallons of litogrhaphers gum (whatever containers it came in) that I use for printing and close to 30 glass bottles with gum mixed with pigments. SOme of the pigments not very much in use and the solutions might be already a few years old. Never saw any evaporation. But then nothing should ever evaporate from a glass bottle. Hey even a bottle of vodka will stay put for years.

Marek 

> Date: Sat, 3 Jul 2010 10:22:39 +0200
> From: tom at sobota.net
> To: alt-photo-process-list at lists.altphotolist.org
> Subject: [alt-photo] Re: evaporation of gum mixture
> 
> I have never used prepared gum solution. I prepare gum in the original
> artisanal way, dissolving gum arabic stones in water. Then, I keep the
> solution in dark glass bottles, well stopped and preserved with a few thymol
> crystals. Kept in this way, I have never observed any evaporation, not even
> in a time span of years. So, what is being described is strange, and
> probably related to the way that the commercial gum is prepared or
> preserved.
> 
> I understand that buying prepared gum is easier and somewhat faster, but it
> is surely more expensive and you never know with any certainty what is in
> there. Preparing gum from bulk gum arabic stones is so easy, that I wonder
> why it is not done more often, at least on the other side of the ocean ...
> 
> Tom Sobota
> Madrid, Spain
> 
> On Sat, Jul 3, 2010 at 3:18 AM, Katharine Thayer <kthayer at pacifier.com>wrote:
> 
> > Okay, that sounds like the standard DS gum, not the premium; I have no
> > experience with that.
> >
> >
> >
> > On Jul 2, 2010, at 5:05 PM, Paul Viapiano wrote:
> >
> > Cool, thanks Katherine...
> >>
> >> The Formulary gum is very light colored, and that's what I've used since
> >> day one. I got the DS gum on sale, great price and it is definitely a darker
> >> maple syrup color. Haven't used it yet...
> >>
> >> p
> >>
> >>
> >>
> >> ----- Original Message ----- From: "Katharine Thayer" <
> >> kthayer at pacifier.com>
> >> To: "The alternative photographic processes mailing list" <
> >> alt-photo-process-list at lists.altphotolist.org>
> >> Sent: Friday, July 02, 2010 2:42 PM
> >> Subject: [alt-photo] Re: evaporation of gum mixture
> >>
> >>
> >>
> >> Hmm, that's interesting. I know nothing about what Formulary is selling
> >>> for gum now, since I quit buying gum from them when they switched from a
> >>> gum I really loved to a dark gummy gum for their premium gum and continued
> >>> charging a premium price for it. That was some years back, and as I said,
> >>> I know nothing of their present gum. The only gum I've seen this happen
> >>> with is Daniel Smith premium gum, and it's been a continuing problem with
> >>> DS gum since I started using it 3-4 years ago. Exact same containers that
> >>> I've always kept my gum-pigment mix in, but with other gums I've never had
> >>> this evaporation problem. With the Daniel Smith gum it's so pronounced
> >>> that the mixes have become more viscous within a short time and dried
> >>> out altogether within a few months, so I've had to throw out the mixes,
> >>> which is very annoying because it's extremely wasteful of pigment. In the
> >>> beginning, I thought it was because the workshop in which I was doing gum
> >>> at the time I switched to Daniel Smith had a bank of west-facing windows
> >>> that didn't open, and it got very hot in there on summer afternoons. But
> >>> the problem continued unchanged when I moved to my present digs, where the
> >>> gum workroom is in a cool basement, so I'm convinced it's the gum (and
> >>> besides, mixes made with other gums and stored in the same containers
> >>> survived that hot workroom quite well and remain fresh and nicely pourable
> >>> to this day).
> >>>
> >>> Whether you can reverse the problem by adding water is a good question;
> >>> in my case, by the time I noticed the increased viscosity, it was too
> >>> late; adding water usually wasn't a satisfactory solution because the mix
> >>> had gotten gummier and the water didn't mix in well. But if you catch it
> >>> fast enough, as you're doing by measuring the loss, it seems as if it
> >>> should work.
> >>>
> >>> Hope any of that is helpful,
> >>> katharine
> >>>
> >>>
> >>>
> >>>
> >>> On Jul 2, 2010, at 1:00 PM, Paul Viapiano wrote:
> >>>
> >>>
> >>> Formulary, til present.
> >>>>
> >>>> Then, will switch to DS.
> >>>>
> >>>> p
> >>>>
> >>>> ----- Original Message ----- From: "Katharine Thayer" <
> >>>> kthayer at pacifier.com>
> >>>> To: "The alternative photographic processes mailing list" <alt-
> >>>> photo-process-list at lists.altphotolist.org>
> >>>> Sent: Friday, July 02, 2010 12:54 PM
> >>>> Subject: [alt-photo] Re: evaporation of gum mixture
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> Paul, what gum are you using?
> >>>>>
> >>>>>
> >>>>> On Jul 2, 2010, at 11:51 AM, Paul Viapiano wrote:
> >>>>>
> >>>>>
> >>>>>
> >>>>> Hello all...
> >>>>>>
> >>>>>> Having traced my pt/pd to a highly alkaline batch of Fabriano , I
> >>>>>> have another question on an entirely different subject.
> >>>>>>
> >>>>>> Sometimes I make these little premixtures of watercolor pigment and
> >>>>>> gum arabic, nice and handy for printing tricolors in the same pigments. I
> >>>>>> mix about 1 gram pigment to 9 ml of gum.
> >>>>>>
> >>>>>> In May, I made a mixture and weighed it at 17.9 grams in its plastic
> >>>>>> snap-cap container. Two months later, it weighs in at 17.2 grams. What is
> >>>>>> it that is evaporating? Gum arabic? I'm curious...
> >>>>>> _______________________________________________
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> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
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> >>>>>
> >>>>>
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> >>>>
> >>>>
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> >>>
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> >>
> >>
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