While buying some new etching blankets from Intaglio I bought a good general
guide to ink on paper techniques called 'The Complete Printmaker'. Whatever its
excellence in other areas it did contain the following interesting advice under
'Lithography, other methods'.
On dichromated albumem:
"Exposure should be made with ultraviolet light. An alternate method of exposure
uses a condenser photo enlarger, which projects the negative onto the sensitised
surface- a procedure that takes longer because of the lower ultraviolet light in
the normal enlarger bulb."
Under ' gum bichromate process' the recommendation is that the paper should
first be coated with acrylic gesso. It should then be sensitised with gum arabic
and dichromate to which pigment can be added. After exposure the print is
developed by holding it under the tap for as long as necessary to run clear,
perhaps 10 to 15 minutes.
And
"Ammonium bichromate is a toxic compound that should be handled with care and
used only with local exhaust ventilation."
Otherwise this appears to be a good and authoritative book.
There is more excitement in 1877 but more of that later.
Terry King