Mask/Holder for 4x5" sheet film

Hello, you can find the info for the 3D printed 4x5! sheet film holder for scanning/enlarging with no glass tables(there is also info in English on that webpage):

Nice. I made something similar recently:

It's a 2-piece design like yours, but with a hinged lid. I included a recess for a little cylindrical magnet in the baseplate and a metal plate in the lid so that it snaps shut. For the hinges I generally melt plain iron nails (1.8mm diameter) through the hinge holes.

Since sheet film is quite stiff, it sort of works OK but for critical sharpness and big enlargements the sag can be a problem. A tensioning system or a glass carrier is preferable for those. These 3D printing thingies work in a pinch and for non-critical stuff.