ABSTRACT
Document films are slow, ultra sharp, ultra-fine grain, ultra-high contrast emulsions. In the 1960s, the document films of choice for making continuous tone pictures were Agfa Copex-Rapid and Kodak High Contrast Copy Pan. POTA is distinguished by the fact that it is in a state of exhaustion from the moment it is prepared, because straight Phenidone is not well preserved in sulfite. The formula to the right is a trial modification in which we try to optimize POTA for document films. A half gram of metol could be added to the Modified POTA formula above, or could replace the pyro or hydro-quinone. As stated, the problem with adding a second agent to POTA is that the better it stabilizes the Phenidone to prevent streaking, the more it raises contrast. Probably the most stabilization with the least rise in contrast will be obtained with glycin.
