U of S | Mailing List Archive | alt-photo-process-l | Re: Miracle size for gum

Re: Miracle size for gum

Marek, and Francis,
Thanks for the posting, Marek.  I will have to try the stuff as well. My results with acrylic sizing in the past have been iffy at best, but perhaps this is the ticket.  I know Peter Blackburn swears by Aquapel, which I also have to try here. So many sizes, so little time....it seems lately when I get time for the darkroom it is time to make work and not do these fun tests which I love to do :(
I just love your posts and tests and visuals--so clear. And your willingness to share your great results.
I am not understanding why it takes 8 hr for water development?  Is that to clear the whites or in general?
Your thalo 1 minute exposure has not printed in the numbers on the step wedge tho it appears you have maximum black in your step wedge--is it 1 minute UVBL or some other light source? You are using a 1 minute exposure normally for your bleach development?? You must be using some powerful light there...the reason I ask is yesterday I gave a gum demo to the Printmaking Club and I guessed the exposure for yellow (ha) might be 8 minutes on their behemoth old exposure unit flatbed thingy and I totally baked the layer on.  I retried at 3 minutes and even that was long.  So I wasted 2 sheets of paper and 11 minutes.  I was basing my guess on previous experience with that unit and solarplate which took way longer than expected (no time to calibrate in an afternoon demo--I just winged it, and you know how that goes...)
You are getting great tonal ranges with your bleaching process of choice.
Francis, Venetian Red is a pretty luscious color, isn't it--a sort of bricky lipstick red.  It's great with a raw sienna and ultramarine blue.  BUT raw siennas sure vary in color, not just in strength, from manufacturer to manufacturer, some being a beautiful yellow and some being a dull ochre. VR is strongly pigmented, too...I used to use it all the time in oil painting.
Christina Z. Anderson
----- Original Message -----
Sent: Saturday, October 10, 2009 7:22 AM
Subject: Re: Miracle size for gum

Being married to a painter, there is a half bottle of this stuff in her studio awaiting my experiments. If it works I will integrate it into the one color gum assignment scheduled for my alt class in early November.

I just discovered Venetian Red and it's my new favorite color. I've gone from one extreme (low tinting pigment) to the other.

One more vendor for Gamblin PVA:



On Sat, Oct 10, 2009 at 8:55 AM, John Brewer <john@johnbrewerphotography.com> wrote:
Is this the stuff Marek? I'm very interested to try this.


-----Original Message-----
From: phritz phantom [mailto:phritz-phantom@web.de]
Sent: 10 October 2009 13:36
To: alt-photo-process-l@usask.ca
Subject: Re: Miracle size for gum

hi marek,
does it really say "pv alcohol" on the bottle, not "pv acetate"?
i found the data sheet on the gamlin site yesterday and there it says:
"Product: Poly Vinyl Acetate (PVA) Glue
Chemical name: Ethylene/Vinyl Acetate Copolymer"


what i've learnt on the substances so far (i think mostly from a post
from katharine thayer on apug), is that pv-alcohol is basically a simple
glue and not waterproof and pv-acetat is insoluble in water and the
better size.


Marek Matusz schrieb:
> Loris,
> A note on the bottle says "post plasticezed neutral pH ply vinyl
> alcohol).
> perhaps one can mix a PVA solution from polyvinylalcohol that can be
> bought. I suspect that there are other additives in the Gamblin
> product, but they might not be all that relevant to the gum sizing.
> I also have to add it is so simple to just take some solution from the
> bottle, add water and brush it on paper, no additional chemicals, no mess.
> Marek
> > Date: Fri, 9 Oct 2009 23:48:02 +0300
> > From: mail@loris.medici.name
> > Subject: Re: Miracle size for gum
> > To: alt-photo-process-l@usask.ca
> >
> > Thanks for the report Marek. Unfortunately we don't have Gamblin
> > products here in Turkey. Do you have any idea about the formula? I can
> > find PVA but I'm not sure which one to buy and how much to use...
> >
> > Not directly related but just wanted to mention: For those who are
> > interested in "casein", the miracle sizing is cheap acrylic gesso 1+4
> > (or 1+5) with water.
> >
> > Regards,
> > Loris.
> >
> >
> > 2009/10/9 Marek Matusz <marekmatusz@hotmail.com>:
> > >
> > >  All,
> > > A few weeks ago there was some discussion on PVA sizing and I
> decided to try
> > > it for gum.
> > > ...
> > > The 1:2 turned out to be a miracle!
> > > ...
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francis schanberger