Judy Seigel (jseigel@panix.com)
Sat, 03 Jul 1999 14:38:16 -0400 (EDT)
On Sat, 3 Jul 1999, Keith_Gerling wrote:
> Hmmm. This raises a question: Is commercially available gum sold with a
> preservative already added? I've purchased from Daniel Smith and the
> Photographers Formulary. I've never added a preservative, and, while I
> generally keep my gum in a cool place, I've never experienced a problem.
> Am I treading on dangerous ground?
It has the preservative already, keeps indefinitely. Non-preserved turns
acid in a few days... It still works; some printers claimed they preferred
it, but it keeps changing -- a variable. What preservative do the
commercial gums have? In the old days a mercury compound, or so I was
told. Now.... who knows, but perhaps one reason for differences among 14
degree baume lithographers gums.
J.
This archive was generated by hypermail 2.0b3 on Thu Oct 28 1999 - 21:40:35