Re: polivinyl alcohol vs. gelatin sizing

From: Katharine Thayer ^lt;[email protected]>
Date: 07/30/05-05:44:27 AM Z
Message-id: <42EB6818.7F5D@pacifier.com>

Schuyler Grace wrote:
>
> KT (or anyone else who might know),
>
> Is there any advantage to using PVA as a gum replacement, or is medium for
> gum printing just a choice of what's readily available (or is GA a better
> medium, for that matter)?

Schuyler,
Some people would say that the advantage to PVA would be that PVA is a
more well-defined chemical entity. I guess the idea is that something
well-defined will be more controllable somehow than something more
organic and indefinite. I would agree that PVA certainly makes it
easier to do *research* about the gum process, because you're working
with a simple, known chemical entity, whereas gum is very complex and
its structure, while somewhat known, is rather indefinite in many ways;
any kind of stoichiometry would be impossible with it. But as far as
making gum prints in practice, I don't see how it's an issue. Certainly
using gum arabic doesn't mean that people can't have control over the
process in practice, and I don't know that those who use PVA have
somehow more control. The chemical structure of the colloid, to my mind,
has little effect on how the process works or whether the printer has
good control over it. I like gum arabic because I just like it as a
substance; I enjoy working with it. PVA seems more impersonal, or less
interesting, or something, to me. Each to his own.
Katharine
Received on Sat Jul 30 12:40:16 2005

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