135 Film Developing Tank

This compact film developing tank is designed for use in a darkroom. It requires less than 250ml of developer and fixer. In addition to the 3D-printed parts, you’ll need a 2mm diameter metal rod to complete the assembly.

I printed mine using an Ender 3 with PLA filament, using a 0.2mm layer height and a speed of 30mm/s. When printing the parts labeled "tube large" and "tube small," be sure to scale them to 101% for the correct fit.

Usage Instructions:

1. Fill the tank with the developer.
2. In complete darkness, load the film onto the reel.
3. Place the reel into the tank and continuously rotate it until the development time is complete.
4. Drain the developer and replace it with fixer.
5. Repeat the same process for the fixer, rotating the reel until the fixing time is complete.
6. Rinse the film in water. (If you keep the tap running, the reel will rotate on its own.)
7. Hang the film to dry.

For ISO 400 film, I used Kodak D-76 (dilution 1+3) at 20°C, with a developing time of 14 minutes. This can serve as a good starting point, but you may adjust based on your film and chemicals.