Re: Chrome Alum Gelatin hardener

Its not so much that I can't find glutaraldehyde as they won't give it to
me!!! I'm used to being patronised (blonde) but it really gets under my skin
when people assume that an art photographer is less reliable with dangerous
substances than a chemist - especially when one is nearly 50! And then -
they hand you a bottle of formaldehyde???????????? Go figure.....

I would use selenium on the shoe because I'm not sure of the effect of the
sepia bleach on leather......on rereading this I see you didn't ever have a
pair of WHITE suede shoes - thank goodness!

cheers
Kate
----- Original Message -----
From: "Ryuji Suzuki" <rs@silvergrain.org>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Tuesday, February 10, 2004 2:33 PM
Subject: Re: Chrome Alum Gelatin hardener

> From: wcharmon@wt.net
> Subject: Re: Chrome Alum Gelatin hardener
> Date: Mon, 09 Feb 2004 19:06:03 -0600
>
> > On a second note, I googled glutaraldehyde, and the first two pages
> > were health warnings and MSDS information about possible side
> > effects from exposure to this chemical. These effects sounded
> > awfully similar to those of formaldehyde. Is there any other
> > inherent advantage other than the ones mentioned. (I guess this part
> > is directed at Ryuji)
>
> The kind of potential problems and typical symptoms may sound similar,
> but glutaraldehyde is much safer than formaldehyde.
>
> In terms of the hardening effects of glutaraldehyde, it is one of the
> most preferred aldehyde hardening agents because of practical
> hardening effects, even among dialdehyde family. For example,
> stability of cross links formed is superior, the range of
> concentrations and other conditions in which hardening effect is
> obtained, the degree of hardening that can be obtained, effectiveness
> as the hardening agent... For example, cross links formed with
> formaldehyde or glyoxal are not very stable, and they can be broken
> with weak acid or high temperature. Cross links of
> glutaraldehyde-hardened gelatin are stable even in dilute acid or at
> boiling temperature.
>
> Kate: we talked about this before... too bad you can't find
> glutaraldehyde in NZ. Unfortunately, this is the best hardener I've
> ever tried, and I can't recommend other compounds from the literature
> because I haven't tried them...
>
> By the way, one of my old shoes I wear in darkroom had white stain
> when I left darkroom last time. It's black now. I suppose this is a
> silver gelatin emulsion printed out on suede leather... Should I tone
> this to make it archival?
>
> --
> Ryuji Suzuki
> "Reality has always had too many heads." (Bob Dylan, Cold Irons Bound,
1997)
>
>
Received on Tue Feb 10 00:05:18 2004