From: Katharine Thayer (kthayer@pacifier.com)
Date: 07/04/03-02:16:52 PM Z
Katharine Thayer wrote:
So yes, folks using
> a very intense, hot light may find that they need to use the slower
> potassium dichromate to keep from overexposing, but folks using
> different lights will find that they can print beautifully in clear
> colors with ammonium dichromate.
Most folks who recommend potassium dichromate over ammonium dichromate
put it in these either/or terms, failing to take into account Judy's
observation that when ammonium dichromate is diluted to the same
concentration as saturated potassium dichromate, the two dichromates
behave functionally very similarly. My comment above should probably be
rephrased to say that gum printers using very intense hot lights may
need to use a lower concentration of dichromate to slow down the
emulsion and avoid overexposing the print; this can be achieved either
by changing to potassium dichromate or simply by diluting the ammonium
dichromate. Folks using cooler lights may find that they can print
beautifully in clear colors uncontaminated by dichromate stain, using
ammonium dichromate at saturated strength.
This archive was generated by hypermail 2.1.5 : 08/07/03-03:34:49 PM Z CST