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,
while it probably is a lot of pigment, i've been doing my test for stain with the same pigment and ratio.
it was almost always 5ml gum + 5ml pot-di sat. + 1gr of iron oxide black powder.
and this is how it printed last week: same mix, same size, same paper (i've already posted it), even the same exposure time.
there is definitely something else going on, that i just can't put my finger on.

and i don't usually keep my mixed solutions for longer, but i coated the first test strip yesterday and kept the rest for a little later. then something else came up and all was delayed until the next day. i've kept mixed solutions for a few days (stored in the dark) before and while there might be small differences in behaviour (i never really checked with a step wedge), they usually print more or less fine.

it's good to hear that your pva works better than the caparol. so there is hope with the substance.


Loris Medici schrieb:
Hi Phritz,

I checked again with a wet hard bristle brush and no gum was lifted
until I finally physically damaged the surface. (I brushed very long
time and very hard.) Conclusion, my version of PVAc glue size is
perfectly fine in that sense. Very tough, very durable and keeps the
exposed/developed layer onto itself.

BTW, it's not a good idea to keep the coating solution (gum/pigment +
dichromate) for a day. You'll get "dark effect". Just mix enough for
immediate use.

I'll repeat that your coating solutions seems to be very high in
pigment load; that's definitely not a coating solution to
expose/develop in the normal way, to my eyes. I'd use that much
pigment only if I plan bleach development...