[alt-photo] Re: Paper Negatives

[Michel Debar]

PVA wood glue used for sizing, is it safe ?

I would certainly worry about the conservation of prints sized with PVA, as
its long term effect on paper has not, to my knowledge, been studied very
seriously. As a minimum, I would stay away from "wood" glue, branded or not.
Its composition has little chance of being  known, and of being stable over
time. The acidity of these glues may vary, and not be suitable for some
processes. They may take as little as five years to become brittle -
however, this may not be not too much of a concern given the very thin layer
used.

If, in later years, a print needs restoration, it will be very hard to trace
the composition of the glue that has been used for sizing, and its analysis
would be at the least costly.

To be on the safe side, you might consider using PVA glues that are meant
for bookbinding, for instance Planatol-BB (or eventually Planatol-B). This
is a glue with a reasonnable history of usage in bookbinding, from a
manufacturer that has proven reliable. See for instance these links :

   - http://www.planatol.de/en/buchbinden/fr_klebstoffe.htm
   - specifically (hoping the link works) :
   http://www.planatol.de/produktgruppe.aspx?ID=0&Language=en
   - http://www.mekatronicsinc.com/machines/pva_history_terms.pdf

Michel

2010/2/22 Loris Medici <mail at loris.medici.name>

> I've also switched to a PVAc based transparent wood glue as sizing. I
> dilute
> it 1+4, gives enough protection for 4-5 layers w/o the sheen of full
> strenght. (I can't say I like the sheen; it takes something from the gum
> prints...) Not that I think gelatin sizing is too much a PITA but it's
> surely much more practical.
>
> OTOH, I'm a little bit nervous about the longterm effects of the sizing to
> the paper and its longevity; because I don't know for sure. Any thoughts?
>
> Regards,
> Loris.
>
> P.S. for Turkey based gum printers: It's "Filli Boya"s (Caparol's local
> brand name) "Fil-fix Şeffaf" transparent wood glue. (You definitely want
> the
> "Şeffaf" version of the glue, there are many Fil-fix products!)
>
>
> -----Original Message-----
> From: alt-photo-process-list-bounces at lists.altphotolist.org On Behalf Of
> Jim
> Larimer
> Sent: Monday, February 22, 2010 6:19 AM
> To: The alternative photographic processes mailing list
> Subject: [alt-photo] Re: Paper Negatives
>
> I really like the PVA for gum prints...the ease of use and the slight sheen
> are definitely pluses for me. I use it full strength on Canson Montval 140
> lb CP.
> Jim L
>
> On Sun, Feb 21, 2010 at 9:04 PM, Judy Seigel <jseigel at panix.com> wrote:
>
> >
> > Thanks for the info... since gelatin sizing is a world class PITA, I
> > will surely try the magic PVA..
> >
> > J.
>
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>



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Michel Debar
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