I am onto a 6 layer gums, and not noticing any particular difficulties with burshing or the bottom gum layer being too fragile. I will check next time I have a layer developing with a more vigorous brushing. I do a lot of brush work on my gums, current work not being so much different and did not noticed problems with the image.
If you were to look at the size it looks pretty wateery to begin with and now I am dilutiong it 1:1 tp 1:2. As I noted before concentration straight from the bottle resulted in flaking on the test strip. Maybe I will try it again and pay more attention to it. Establishing the right concentration to apply seems to be critical.
Phritz, do you soak your paper before hand. It seems like that helps by raising the nap of the paper a bit.
On the other hand I tested a copule more papers with a 1:1 dilution, BFK rives, which looked like a blottong paper, very porous and with a lot of tooth (actually I got an email that somebody has been using it for a while and sizing it with streight form the bottle Gamblin PVA with wonderful results). Just printed a blue layer on it. Looks so nice. Same thing for lana lanaquarelle, which seems very heavily sized to begin with, but printed very well with a 1:1 size. The third paper is Magnani Pescia. This paper is very open textured and has a lot of tooth. It does contain UV brightener as it glows white under UV light. It printed well. I will be working on multilayer gums on these papers over the weekend
Her eis a 4layer print. I have been doing this very free style prints with very rough coating, partial coating, etc, trying to have them look like totally hand made prints.
> Date: Fri, 23 Oct 2009 17:08:43 +0200
> From: email@example.com
> Subject: Re: My own PVA glue sizing experience (attn: marek + the gum woes again)
> To: firstname.lastname@example.org
> hi loris,
> maybe it's a different recipe after all. i don't have any coating
> problems at all, not even at a 1+1 dilution. at 1+1 there is a little
> beading action when the emulsion is first applied, but it smoothes out
> fine, even before i start with the second brush.
> i can't get around the problem with the bad adherence of the exposed gum
> (with my caparol binder size)
> it took me while to notice (at first i thought it's the strength of the
> red layer that overpowers the yellow one), but brushing on another layer
> on top of an image, brushes off parts of the layer beneath.
> it's a dilemma, single layers print absolutely beautiful, but if i can't
> print multi-layer, it's unusable. i've now checked with different
> dilutions (1+4 and 1+20) and with exposure times from 1min to 9min
> (images print fine at about 1:30). a little brushing with a wet brush on
> a dried print and it comes right off. it sticks a little better at the
> 1+20 dilution, but not much.
> i'm thinking now about diluting the pva with gelatin, to maybe get the
> best of both worlds... but this would need hardening again and all
> advantage would be lost. most likely i'll just order the gamblin.
> marek, did you ever notice bad adherence with the gamblin size? could
> you maybe check with a wet brush on a discarded test print? with a
> higher dilution of the gamblin, if possible?
> and to annoy people one more time with my ugly test strips:
> i finally got the stain with the caparol size too. i'm now sure it's
> nothing in the material. this only leaves either a combination of
> various minor influences or humidity.
> i don't use a preservative in my gum stock solution, so i keep the
> bottle in the fridge. sometimes i use it cold, right out of the fridge
> and i did a test to see whether the temperature has an influence or not.
> this is one sheet of paper, sized with 1+4 caparol binder, cut in three
> . the bottom strip is the "cold gum" mix. the middle one (not beautiful,
> but stain free) is coated the next day with exactly the same emulsion- i
> kept it in the closed mixing vessel overnight (also notice the reduced
> sensitivity). the top strip is a mix applied freshly, the same
> proportions/ pigment as before.
> i'm definitely buying a hygrometer now.
> best regards
> Loris Medici schrieb:
> > I've tried the a local Caparol product "Fil-fix", which according to
> > the product information sheet is "a PVAc dispersion wood
> > furniture/cardboard/paper glue which dries to form a strong, flexible
> > and transparent film". I diluted the glue 1+2 with water. It was a
> > quick-n-dirty step table test just to get a feeling about the new
> > sizing. See notes below:
> > - Dried surface is glossy but not too much. Wasn't objectionable to me
> > but it's definitely more shiny compared to the virgin surface. Can say
> > that it's slightly more shiny than 3% formalin hardened sizing (yes,
> > gelatin sizing also makes the paper shiny, albeit in a different
> > manner). Also, the dried surface is considerably more gritty compared
> > to the non-sized portions (good for gum I presume since it means more
> > texture to cling on).
> > - Application of coating solution wasn't easy, the sensitizer tended
> > to bead and form small fisheyes. Anyway, I was able to even it by
> > using an extra smoothing brush. I normally use a single smoothing
> > brush, this surface required two (because the first one got
> > saturated).
> > - Development and the result was normal except for the fact that parts
> > of the image that got no or very little exposure (specular highlights)
> > dissolved and left the surface in a snap. (Usually it takes 5-10
> > minutes...) Read as "very effective pigment stain inhibitor".
> > - Wet gum emulsion is not more vulnerable than what it is on a surface
> > with conventional sizing. It behaves pretty much in the same manner.
> > Haven't tried to print a second layer, I just manipulated the
> > developing print with a pretty stiff brush, harshly.
> > - In general my experience was positive. I'll try it diluted 1+3 or
> > even 1+5 later; hoping to get a less glossy surface / facilitate
> > application.
> > Hope this helps, somehow!
> > Regards,
> > Loris.
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