I have a 100 sheet box of x-ray dup film but have had inconsistent results with it. I have had some success with D-72 and also with a developer I got from my dentist. The stuff from my dentist came with a bottle of fixer. The bottles were just marked "Developer" and "Fixer" and the wholesalers name and contact info. They were also marked to be used full strength. The developer had a very short life once the bottle was opened.
What developer do you use? Where do you get it?