[alt-photo] Re: Paper Negatives

[Loris Medici]

Yes, I feel the same about "not being studied very seriously" in the general
sense. OTOH, the content is described as "aqueous polyvinyl acetate
dispersion". It's not a wood product exclusively; the product datasheet
states: "general purpose glue for wood, paper, cover ect.", sorry for the
confusion, my bad. And your suggestion Planatol-BB description is equally
vague: "Universally applicable dispersion glue for all manual gluing jobs
involving absorbent materials..." Therefore, albeit being from a more
respectable brand, that product also is a black box to me, in the academic
sense.

The product I'm using is definitely suitable for gum dichromate IME. (I mean
it doesn't have a negative effect on the process; it works in a pretty
normal way.) I also thought about bookbinding glues but couldn't find a
product that was sold in small amnts; making research expensive to me.

BTW, I know there are many other practitioners using similar products not as
a size but (even!) as their "pigment binder"; see "Gloy" prints by some
English people, others (Americans) using "Elmers Glue", I also happen to
remember Jean Janssis' Mowiol (88% hydrolized PVAc) prints and so on...

Now, I'm not seaching for a justification at all and as you can understand I
have mixed feelings about the practice, simply because I don't have enough
data. (Same for all the products / methods mentioned above.)

Thanks & regards,
Loris.


-----Original Message-----
From: alt-photo-process-list-bounces at lists.altphotolist.org
[mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On Behalf Of
Michel Debar
Sent: Monday, February 22, 2010 11:50 AM
To: The alternative photographic processes mailing list
Subject: [alt-photo] Re: Paper Negatives

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.
>
> _______________________________________________
> Alt-photo-process-list | http://altphotolist.org/listinfo
>



--
Michel Debar
11, chemin du Fort Saint-Héribert
5100 Wépion Belgique

Tél. +32 (081) 4612 04 - +32 (0485) 72 83 92
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