Unlike many 110 cameras the Pentax auto 110 does not require perforations in the film, so you can pretty easily slit down 35mm film to 16mm and reload old cartridges. You can do it without the backing paper, but re-using old backing paper is even better. An article about this is here: http://subclub.org/darkroom/roll110.htm I use the "Al Spoil" film slitters: http://www.subclub.org/sponsors/goathil2.htm You see them on ebay pretty often. It helps avoid emulsion scratches if you pull a second, already slit film, under the emulsion as you slit.