What kind of film do I need to use to make positives?

It really depends on the type of ink that the printer uses. For example, Epson makes many types of printers that use either photographic dye, Ultra Chrome pigment or Ultra Chrome K3 inks.

If the printer uses DYE based inks all of our Accu-Family of ink jet will work very well. If pigment based Ultra Chrome is used the field narrows to AccuArt 2 and AccuArt 3. The new printers from Epson that say they use Ultra Chrome K3 inks will require you to use AccuArt 3 media. Every ink jet manufacturer has their own types of inks but they still fall into either dye or pigment. The best way to find out what media you need is to call Chromaline and ask for guidance and a sample to do some testing on your own at your shop.