>I remember posting about using MINIMUM dichromate to do the job, a couple
>of years ago with the discussion of whether dumping dichromate down our
>sewer systems was a good thing. How much dichromate does it take to
>sensitize gum? Has anyone tested it?
>
>Not that I am necessarily doing it any better, but my method is quite
>different from what "the books" suggest: I dilute my gum with water first,
>add pigment till I get the colors I want, THEN add enough dichromate in
>powder form to the mixture. The amount I use is from what Franklin Enos
>taught me, which is about a quarter of what it takes to get a saturated
>solution.
>
>If we were talking about carbon, that would be a different story. The
>amount of dichromate determines contrast in carbon printing. In gum, my
>understanding is that it does not have the same effect, i.e. more
>dichromate may make the emulsion slightly more light sensitive, but that's
>about it. I would love to hear from someone who have found otherwise.
The proportion of dichromate does affect contrast from my experience. I
use two dilutions of a 29% amm dichomate mix. One at 2:1 (2 parts
sensitiser to 1 part gum) and one at 1:1. The 2:1 gives less contrast and
I usually employ it around the second or third coating.
>
Hamish