Re: PVA for gum printing

From: MARTINM ^lt;[email protected]>
Date: 09/08/04-06:08:21 AM Z
Message-id: <000901c4959c$8dcf8200$40aea2d9@MUMBOSATO>

> Why do you say that?

Simply - if ESTAR was an unsaturated polyester (say based on styrol) chances
would be high it's fairly different from PET. Maybe not so much with regards
to dimensional stability but rather with regards to chemical stability
(which may lead to different approaches to make a layer of gelatin, gum etc.
stick on it).

> You can find some of the polyester films that are available pre-subbed
> with gelatin. One is from Grafix in their Duralar line.

Thanks for that information! On their website
(http://www.syscontech.com/supplygraph/grafix.htm) they say:
" Dura-Lar combines the best features of acetate and mylar to give you the
optimal performing film. Perfect for layouts, color separations, protective
covering, drafting and drawings." Which film would be pre-subbed with
gelatin?

Martin

----- Original Message -----
From: "Ryuji Suzuki" <rs@silvergrain.org>
To: <alt-photo-process-l@sask.usask.ca>; <martinm@SoftHome.net>
Sent: Wednesday, September 08, 2004 9:48 AM
Subject: Re: PVA for gum printing

> From: MARTINM <martinm@SoftHome.net>
> Subject: Re: PVA for gum printing
> Date: Wed, 08 Sep 2004 08:45:04 +0200
>
> > One source classifies ESTAR as polyethylene terephthalate (PET) and
> > the other one, probably more likely so, points out it was formed of
> > unsaturated polyester (UP). The latter would be significantly
> > different from PET.
>
> Why do you say that?
>
> Poly(ethylene terephthalate) is a polyester. Do you see the bond
> between O of the terephthalate and carbon of the ethylene group?
>
> As far as I know, all polyesters that are used as an emulsion
> substrate are poly(ethylene terephthalate) and they all have the
> coating difficulty you described. However, they are preferred because
> of mechanical strength, dimensional stability, chemical stability,
> archivalness, and what not.
>
> You can find some of the polyester films that are available pre-subbed
> with gelatin. One is from Grafix in their Duralar line. I am curious
> about that product but I haven't got to try it myself yet.
>
> --
> Ryuji Suzuki
> "You have to realize that junk is not the problem in and of itself.
> Junk is the symptom, not the problem."
> (Bob Dylan 1971; source: No Direction Home by Robert Shelton)
Received on Wed Sep 8 06:06:16 2004

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