Polagraph will certainly boost contrast. Unfortunately it is a specialized
emulsion and only available in 35mm and not amenable for processing in standard
chemicals. Actually, Polagraph and Polapan are more like "reversal" processes
than Direct Positive ones now that I think of it.
I have never used Kodak's Direct Positive material but would suspect it's
response could be altered by various development factors.
andy o o 0 0 o o Andrew Davidhazy, at RIT's Imaging and Photo Tech Dept
\/\/\/\/\/\/ andpph@rit.edu High Speed Photography Lab
________| |__________________________________________________________