Rocker Tray Film Developing Tank Concept

(Rocker tray animated via bent map pin)

I'm constantly brainstorming ideas for camera and darkroom devices. Here's a recent example.

This page is from my Handi Desk journal: an animated concept for a tabletop sheet film/paper developing tank. The device sits on a table. Pour the chemicals (developer followed by stop bath followed by fixer) one-at-a-time into the top. The liquids flow through the light trap into the tray.

An axle connected to the tray protrudes through light seals in the sides of the device to a pair of knobs (not shown in the sketch), used to manually control the tray. Gently rock the tray via the knobs for the duration of the step.

Place the chemical bottle in the bottom, under the dump port, and then rotate the tray 90 degrees to empty its contents back into the bottle. Upright the tray to level. Repeat with the rest of the processing chemicals.

The top half of the device removes, to gain access for loading and unloading the film or paper.

The sheets of paper or film are loaded into the device while it's inside a large light-tight changing bag or tent; or alternatively, loaded in the darkroom, then brought out into the light for processing. This sketch is conceptual in nature, not representing a finished design. The main hinderance to functionality is the loading and unloading. To be used out in the field, such as on a folding table or from the back of a vehicle, a changing tent, at minimum, is required, to transfer the film or paper from sheet film holder to the tray.

I've found often that these kinds of conceptual sketches, rather than revealing new and innovative designs, instead prove why tried-and-true ideas are so worthwhile. In this case, a simple developing tank made for 4x5 film would work just as well, and be smaller in size and simpler in complexity. However, as a habitual sketcher, I find some solace in the notion that even dead-end designs deserve to be documented, if for no other reason than explaining why they shouldn't be pursued.

This concept may prove useful if included as part of an Afghan Box Camera, where the processing section is separated from the camera itself. Simply design this device inside a larger enclosure that has a pair of arm sleeves. Once the film or paper is loaded, processing can proceed in daylight.