Re: PVA for gum printing

Having read some conflicting statements about its composition, I am not sure
about Estar. If Estar was similar to PET (polyethylene terephthalate),
that's to say Mylar, Cronar etc. it would require a great deal of effort to
coat gelatin or gum on it like: flame/plasma/corona treatment, etching etc.

TAC (triacetate) film is a lot easier to handle: 2 min in a 10% alkali
hydroxide + (deonized) water rinse will do the job.

Martin

----- Original Message -----
From: "Robert Schaller" <Robert@RobertSchaller.net>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Monday, September 06, 2004 7:35 PM
Subject: Re: PVA for gum printing

> Dear Katherine,
>
> I indeed can't see why mylar would introduce any impurities, certainly
> not water-soluble ones, and wouldn't these be the problem? I also want to
> applaud your efforts in this, as it seems long overdue that someone
conduct
> this investigation in an orderly, scientific fashion. I wish I was set up
> to do it. I am curious about how the investigation will proceed. What
> tests exactly is the chemist planning to do? I get the impression that
just
> hardened gum (or PVA) will be tested first; what next? As I said, I am
very
> curious.
> Also, on the point of gum on hard surfaces. What about ( and this is
> probably my question more than yours) getting gum to stick to polyacetate
or
> polyester (Kodak's 'Estar') film base? The issue seems related, in that
it
> is really asking, how do you get gum to stick to a non-water adhering
> surface, be it rigid or flexible? I have cheated and used Kodak's already
> adhered gelatin layer as a subbing layer,as it is already there and is
> optically transparent, but this avoids the question. Obviously, Kodak et
> al. know how to get gelatin to adhere -- what's their trick, and would it
> work as well for gum? Does anyone have any methods, ideas, or
suggestions?
>
> Robert Schaller
>
>
>
> On 9/4/04 3:32 AM, "Katharine Thayer" <kthayer@pacifier.com> wrote:
>
> > Katharine Thayer wrote:
> >>
> >
> >> Do you or anyone know of any reason why mylar shouldn't be used for a
> >> substrate for hardening the gum?
> >
> > No one has answered this question; I take the silence to mean that no
> > one knows any specific reason to distrust mylar as a substrate. At any
> > rate, I will wait for the go-ahead from the chemist to be sure, before
> > finishing the project on mylar. Thanks for suggestions,
> > Katharine Thayer
>
Received on Tue Sep 7 01:37:31 2004