Increasing Carbon speed.

         I am reading in " Photogravure" by H. Mills Cartwright Page 65 that
carbon tissue at a ph of 4.0 or less that the speed is high but has a
tendency to fog... As speed decreases Ph rises. It also states that the
addition of small quantities of chlorides of rare metals such as cerous
chloride and conditioning it by ph can also increase speed... Adding
chromic salt of Pyridine , or soluble salts of cerium or lanthanum
chromates also increase speed... Has anyone experimented with this?
Received on Mon Dec 13 00:54:45 2004