| http://www.w3.org/ns/prov#value | - When the color former employed in the CB coating is a chemically basic chromogenic material, any known acidic developer material can be employed in the CF coating, such as, for example and without limitation, clays; treated clays (U.S. Pat. Nos. 3,622,364 and 3,753,761); aromatic carboxylic acids and metal salts thereof (U.S. Pat. No. 4,022.936); phenolic developers (U.S. Pat. No. 3.244,550); acid
|
