Digital BW, The Print

Hi, I am interested in gum arabic printing. This method of printing a
negative uses gum arabic and a watercolor pigment, with a sensitizer-
potassium dichromate. The dichromate renders the gum arabic insoluble
in water on exposure to light. The print is developed in warm water.
The unexposed portions of the print dissolve. I want to find another
chemical rather than the dichromate to use. This chemical is too toxic
for home use and a substitute is needed. Does anyone know of another
chemical which will release oxygen on exposure to light like the
dichromate? Alternatively, a chemical that would produce acidic
conditions on exposure to light would also render the gum arabic
insoluble.

Best Regards

Jim