A small 24 V centrifugal pump moves the water in the JOBO CPE2 bath. Five-probe logs before and after: heating speed barely changed, the bottles ran close together, and the bath now shows the thermostat’s on/off cycles.
The JOBO CPE2 and CPE2+ are still among the most common rotary processors in home darkrooms, but they are decades old, and the small plastic parts go first: the bottle frame cracks, drum rollers and their holders go missing, knobs break or simply disappear. Original spares are hard to find, and when one does turn up, it usually costs far more than a small piece of plastic should. So I designed printable replacements and upgrades for my own CPE2 and collected them in one open repository: ...
The Problem with Existing Film Tanks If you develop film in a darkroom, you know the frustration: almost every tank on the market leaks chemicals from the top when inverted. Paterson, AP, and most other systems all have this issue. The only exception is Jobo — but it comes at a cost. Inversion agitation is inconvenient, messy, and completely incompatible with automated film development setups where precise chemical dosing matters. ...
Open Hardware Reels: A Better Way to Develop Film I have designed a new type of open-source film developing reel specifically optimized for 3D printing. While many designs exist online, most are not tailored for home manufacturing, leading to failed prints or poor functionality. These reels are fully compatible with the standard systems like Paterson system and can be printed at home using common materials like PETG without supports and from two pieces. ...
Purpose The main purpose of this tool is to create a better way to load film onto existing Paterson reels, and also to take the first steps toward an automatic loading mechanism for a Film Development Machine project. Because I decided to work in step-by-step iterations, this is a good start — a mechanical prototype that resembles the loading mechanism planned for the final machine. Materials and Production It is preferable to print from PETG, ABS, or other materials that are less brittle and more flexible. The parts have flex points and clicking mechanisms for film holding and for paper winding in the case of the 120 jig. Both tools print in 2–3 hours without supports and are designed to be printable with most modern print technologies available on the market. ...