Re: gelatin hardeners

From: "Robkin, Eugene" <erobkin@uwc.edu>
Subject: RE: gelatin hardeners
Date: Tue, 10 Feb 2004 08:37:24 -0600

> Look here first before going this route. It is something for people
> with professional skills.
>
> http://www.cdc.gov/niosh/2001-115.html
>
> There were a lot more hits on the glutaraldehyde search than this one of
> course but this covers the ground.

This is very misleading in three ways.

1. Glutaraldehyde is used in many places by professionals, while
   glyoxal and formaldehyde are less commonly used. This is why you
   see more health warning for glutaraldehyde than formaldehyde or
   glyoxal.

2. The amount of glutaraldehyde used for photographic hardening is
   much less than sterilization of one small surgical
   instuments. Compared at the same concentration of glutaraldehyde,
   sterilization needs complete immersion of the tool in the solution,
   while hardening of photographic gelatin requires a few drops for
   emulsion required to coat 11x14 paper. Much of glutaraldehyde
   molecules mixed with gelatin solution are bound to gelatin matrix
   in a few moments, especially if the gelatin concentration is more
   than a few per cents in water, leaving much less free
   glutaraldehyde molecules.

3. There are many many other compounds commonly used in alternative
   processes that are just as damaging to living tissue, but those
   chemicals are not routinely used by many professionals, not many
   health warnings are not issued.

I'm not saying glutaraldehyde is a safe chemical. I'm saying it is
very misleading to overemphasize its hazard while not comparing to the
hazards of chrome alum, potassium dichromate, other metal salts,
selenium toner, and other chemicals people commonly use in this
community.

--
Ryuji Suzuki
"Reality has always had too many heads." (Bob Dylan, Cold Irons Bound, 1997)