Re: Water and gum coating

From: MARTINM <martinm@SoftHome.net>
Subject: Re: Water and gum coating
Date: Thu, 20 May 2004 09:18:48 +0200

> I guess a great many photopolymer system exist that may work in that sense.
> E.g. acrylamide systems achieve speed levels somewhere between silver
> halides and dichromates. In addition they can be spectrally sensitized:
> erythrosin, rose bengal etc. for green and methylene blue for red exposures.

Is there a reason why erythrosin is preferred for that wavelength over
cyanin or merocyanin dyes of similar absorption spectra? Well,
erythorosin is very cheap anyway, one good thing if it works.
(So is methylene blue.)

> Adding PVA to the solution will provide sufficient protection from oxygen
> (which inhibites radical polymerization).

But your formula is not adding PVA to the acrylamide stock but adding
to the dye stock instead. Why?

Can you really get enlarging speed with it?

--
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)