gelatin hardening (was Re: Glutaraldehyde: a different kind of cautionary tale)

From: Ryuji Suzuki ^lt;[email protected]>
Date: 05/06/04-07:39:33 AM Z
Message-id: <>

From: MARTINM <>
Subject: Re: Glutaraldehyde: a different kind of cautionary tale
Date: Thu, 06 May 2004 14:24:29 +0200

> Moreover there is heat treatment (which may not simply cover baking
> but also micro-wave exposure) to provoke strong crosslinking. Heated
> gelatin is said to form in situ aldehydes.

Are these techniques used for any photographic products? I don't
think so. For one thing heating of gelatin affects too many factors
and using chemical agent is more controllable way to accomplish
hardening. Aldehydes are a known microconstituent of gelatin products,
although photographic gelatin is produced so that it is free of

> Though producing similar effects as more conventional hardeners, I
> am not sure whether introducing monomers into a gelatin layer that
> are subsequently polymerized, may be regarded as hardening.

What is being polymerized?

> It seems to me hardening involves the melting point of gelatin to be
> risen. However, this appears to be somewhat ambivalent since
> gelatin concentration is likely to have a large impact on gel
> strength.

> One criterion might be to what degree/at which temperature gelatin is
> swelling - that's to say, the quantity of water bound within the layer.

Hardening is a way to influence the mechanical properties of gelatin
in gel state. This is most commonly measured as amount of swelling of
gel at a certain standard condition. Melting point also changes, but
it is less readily measurable quantity.

Ryuji Suzuki
"All the truth in the world adds up to one big lie." (Bob Dylan 2000)
Received on Thu May 6 08:14:53 2004

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