Re: Help with what I believe is a hardening issue

From: Ryuji Suzuki ^lt;rs@silvergrain.org>
Date: 11/13/04-06:10:12 PM Z
Message-id: <20041113.191012.97296866.lifebook-4234377@silvergrain.org>

Thanks Joe, Katharine, and Tom for inputs.

So I went to buy a Liquitex Clear Acrylic Gesso and coated a bit of
paper with my fingers, both undiluted and diluted. I feel very gritty
touch when I spread this on paper, though the liquid is not very
gritty at all. I feel this product might contain some matting
agent. Is this consistent with others' observation?

I avoided nonclear, white Acrylic Gesso because the white pigment is
most likely titanium dioxide, and I am not certain those manufacturers
take strong measure to prevent its catalytic action on oxygen to make
ozone.

Come to think of acrylic compounds, many commercial silver gelatin
products use compounds like polyacrylamide in addition to gelatin, for
substrates, emulsion layers, and overcoats. I guess polyacrylamide
plus gelatin is the way to go for smoother surface. Polyacrylamide is
an interesting polymer, which mixes with water at any proportion, but
can be hardened with glutaraldehyde (and triazines, active vinyl
compounds, epoxisides, etc.) to make insoluble solid, which is still
permeable to water and other stuff. So this is used for soft contact
lenses, etc. (Index of refraction is close to that of water when wet.)

Also, polyacrylamide+gelatin+glut may be a possible direction to try
for Sandy's problem to increase the glow on non-gelatin based
process. Maybe dextran in place of or in addition to polyacrylamide.

--
Ryuji Suzuki
"You have to realize that junk is not the problem in and of itself.
Junk is the symptom, not the problem."
(Bob Dylan 1971; source: No Direction Home by Robert Shelton)
Received on Sat Nov 13 18:10:46 2004

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