U of S | Mailing List Archive | alt-photo-process-l | Re: My own PVA glue sizing experience (attn: marek + the gum woesagain

Re: My own PVA glue sizing experience (attn: marek + the gum woesagain)

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: http://i31.photobucket.com/albums/c367/phritz/1-2.jpg
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 pieces
. 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
- 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

Hope this helps, somehow!