Half-frame 35mm Negative Holder compatible with Pentax 17 and Valoi base

This is a negative holder for 35mm half-frame images, such as those produced by the new Pentax 17 camera.

This negative holder has the correct lugs and size to fit on the Valoi360 advancer base, but you can use this with any light source.

I have included the FreeCAD file so you can make any adjustments you wish. The important dimensions are parameterized in a spreadsheet, so you ought to get it working for you.

Print two of them, placed on their sides with the pins facing up. This is necessary so that the film path is in line with the filament and doesn't have steps. I printed this in Prusament PETG with supports only on build platform--the supports were for the lugs on the bottom.

You will likely have to clean up the print quite a bit. Don't even think of using abrasives on it since any grit will get lodged in the film path and will scratch your film.

Before gluing up, I made sure that I could get a piece of film to fit through the device when assembled. Once I got one strip of film sliding through roughly, I was able to feed in a second strip, using the first to drag the second in with it. I then worked the double thickness of film back and forth through the assembled device until the film path was smooth enough for a single strip to move freely.

Only after it was perfectly smooth did I glue it up. Be careful to not get glue in the film path.