I find that if one washes a gum print in gently running water for six hours, it
will clear to the effect that there is no discernible difference in colour
between that of the print and my undichromated test swatches.
If I wash the print for another two hours, I can print silver processes on top
of the gum with there being no trace of oxidisation ( bleaching ) of the silver
by the dichromate. This is certainly true after fifteen years.
Terry King
The impossible will take until Tuesday.