Re: PVA vs. PVA

Since no one answered my question about why PVA rather than acrylic, I
decided to answer it myself and went out to size some papers with (1)
PVAcetate and (2) acrylic medium, to print with gum and compare. But
right away I realized I have a problem, because my PVAcetate doesn't mix
with water; it precipitates out in clumps when mixed with water. Since
I'm not interested in messing with other solvents, I think this is one
question I'll just never have an answer to. Such is life,
Katharine

Giovanni Di Mase wrote:
>
> What I am basically working is to produce very large paper prints of 1.00
> mts x .80 mts using alternative processes.
> Yesterday I prepared a hand made paper of that dimension and "drunk" 150 cc
> of PVA acetate sizing at 1:5 ratio (it also gained weight).
> This was a single sheet of paper.
> So far my tests with 60 cms x 40 cms prints are fine (I am using Cyano and
> Van Dyke so far but I will move afterwards to gum bichromate).
> I found that PVA acetate sizing for these dimensions and eventually number
> of prints is easier than gelatin+hardener sizing but I will only know at the
> end.
> I hope this explanation complies with your WHY question.
> Giovanni
> pd No problems producing a large negative and getting the proper UV source.
>
> ----- Original Message -----
> From: "Judy Seigel" <jseigel@panix.com>
> To: <alt-photo-process-l@sask.usask.ca>
> Sent: Monday, August 01, 2005 11:30 PM
> Subject: Re: PVA vs. PVA
>
> >
> > On Mon, 1 Aug 2005, Giovanni Di Mase wrote:
> > >
> > > Any idea what the stock ratio (dilution, pigment and bichromate) and
> would
> > > be using glue (any Elmers or Gloy) instead as arabic gum to start with?
> >
> > I'd start with normal gum ratio, which goes anywhere from equal to 1 to 2
> > to 2 to 1 or more I suppose.
> >
> > > I am assuming that Gloy is manufactured out of PVA acetate as all other
> > > glues and as I read from Katharine it is not water solubable therefore
> could
> > > not replace the arabic gum, but I have also read the opposite
> >
> > If it isn't water soluble when it's dry, obviously you can't make a gum
> > print with it, because it won't differentially dissolve. On the other
> > hand, whatever you're using for a size, has got to be NON-water soluble,
> > or it will wash off even as you coat the emulsion.
> >
> > > I am going to try anyway and compare to the PVA alcohol glue, I just
> need to
> > > have some clear ideas from where I am going to what I can find.
> >
> > Well, I think one more thing, though I hope you won't think I'm being
> > snide... That is, WHY ? I mean, what benefit do you expect from what are
> > after all marginal, or anyway minority materials? Which is not to say
> > there are none (as I recall Joe Smigiel uses rabbitskin glue) but I have
> > yet to get an idea from this discussion of what they're supposed to be. (I
> > remember, BTW, in fact I have samples in the file, how hard Mike Ware
> > worked to get decent gradation with PVA. Not to say he didn't ultimately
> > get it -- I have no idea -- but that gradation is almost unavoidable with
> > a properly coated, exposed, and developed *gum* print.)
> >
> > That goes not just for you of course, but for the whole discussion.
> > What is it about?
> >
> > Judy
> >
Received on Fri Aug 5 12:24:38 2005