Re: Chromalin
Pollmeier Klaus (100561.2417@compuserve.com)
05 Mar 96 02:17:44 EST
Diazo sensitizers would work on gelatin (Ultrastable...) or other colloids, but
allow halftone work only. Although it would be fine to use them, as they are
much safer than dichromates and allow presensitizing for weeks or months, they
are much too contrasty for usual continuous tone negatives. If I understand the
book I have at hand correctly, a certain amount of energy is required to change
the structure of the diazo sensitized colloid, so even soft negatives wouldn't
help. But with a very fine irregular screen (forgot the word again: frequency
modulated pattern) it might work and you would not see the sreen in the final
print.
Some diazo sensitizers make an unsoluble colloid water soluble (the chromalin
version), others behave like the dichromates and make a water soluble colloid
unsoluble.
Klaus Pollmeier
Klaus Pollmeier