Re: Hardening gelatin with formaldehyde

It's me! I haven't had any fogging problems at all.....when I asked for
glutaraldehyde, they acted as if I was Dr Frankenstein....I also add
glycerin as a plasticiser. No problems so far.....

Kate.
----- Original Message -----
From: "Ryuji Suzuki" <rs@silvergrain.org>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Friday, March 19, 2004 12:52 AM
Subject: Re: Hardening gelatin with formaldehyde

> From: "Dr. Bruce E. Kahn" <bkahn@mail.isc.rit.edu>
> Subject: Hardening gelatin with formaldehyde
> Date: Thu, 18 Mar 2004 03:51:02 -0500
>
> > In the conventional AgX photographic world (as opposed to alt),
> > formaldehyde hardening caused a number of other problems (other than the
> > ones discussed here). It is a reducing agent and can create fog,
>
> Point well taken -- indeed, I mentioned this problem a bit while ago,
> but silver gelatin processors are very minority here (I only know a
> few) and some people (probably deliberately) misunderstood that the
> shortcommings of formaldehyde only applied to AgX processes... so I
> purposely avoided this topic. It's not always scientific here...
>
> Plus, at least one person on this list is using commercial liquid
> emulsion with formaldehyde hardening because she can't find
> glutaraldehyde. She doesn't seem to be annoyed by fogging problem...
> it maybe because the liquid emulsion is very slow and also added lots
> of stabilizers and antifoggants.
>
> > [...] and can cause afterhardening. This later
> > point may be important for those of you here. Basically, it means that
you
> > can't stop it from doing it's thing. Even when you think that the
> > hardening is finished it can actually keep going. Overhardening is
> > bad! So if you are interested in doing alt for archival reasons, you
> > probably shouldn't use formaldehyde hardening of gelatin.
>
> Related to this point, I also discussed disadvantage of chrome alum
> hardeners here, but some people still favor chrome alum over
> formaldehyde or glyoxal... and not considering glutaraldehyde. I don't
> understand it.
>
> --
> Ryuji Suzuki
> "All the truth in the world adds up to one big lie." (Bob Dylan 2000)
>
>
Received on Thu Mar 18 14:17:53 2004