Wayde Allen (wallen@boulder.nist.gov)
Tue, 02 Nov 1999 09:40:42 -0700 (MST)
On Mon, 1 Nov 1999, Judy Seigel wrote:
>
>
> On Mon, 1 Nov 1999 FotoDave@aol.com wrote:
> > The cases that I have seen were gum arabic rather than gelatin, but I am sure
> > the organisms (and large organisms too like cockroaches) love jello as well
> > as gum drops.
>
> However, it should be pointed out that the gum arabic in a gum print is
> hardened by the action of the dichromate, which has a tanning effect. It
> might have some effect on the gelatin, too, but not in the parts where
> there's no tanning -- that is, on the highlights.
Yes, and I would also suggest that hardening the gelatin probably doesn't
really protect it much, if at all, from attack by insects or microbes.
> You maybe don't scratch it during processing, maybe or maybe not so
> readily in a 35 mm tank either -- however just pulling it in and out of a
> sleeve with a microspeck of grit on it can make a dandy scratch -- not to
> mention moisture, splashes, wet emulsion, all the other ills film is heir
> to.
And this brings up another question of mine, namely does this so-called
hardening actually increase abrasion resistance or does it merely serve to
strengthen the crosslinking in the wet gel making the wet film a bit
tougher and less water soluble? It isn't clear to me that the dry gelatin
film is greatly affected by this "hardening". Is that really true or just
an assumption?
- Wayde
(wallen@boulder.nist.gov)
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