> that one), but isn't potassium dichromate more concentrated in a saturated
> solution, and if so, wouldn't this salt be better in terms of maintaining a
> higher viscosity emulsion and thus minimizing the stain problem? Maybe I've
> been using the wrong salt all along. Is potassium dichromate best suited for
> the process? >>
This is an interesting point. I suspect that one of the main contributors
to staining is the gum becoming too thin - either through further
dilution, or too much sensitizer - though increasing the amount of
sensitizer doesn't seem to cause additional staining - though increasing
the amount of pigment in the gum can do. Maybe its the carrier of the
pigment in solution in the tube watercolours that is a contributor...
Hamish
>