Constant Agitation

[mrred]

I would imagine this device does not address an issue of tanks / trays not completely filled with developer. Drums rotate and trays can be tilted to cover the film.

Interesting, none the less.

 

[mrred]

It would be interesting how an ultrasonic tank would fair. As long as it would leave the emulsion where it is supposed to be.....

 

[Sirius Glass]

I have a JObo CPP2 and I use "P" for the smaller thanks and "4" for the Expert Drums and large drums for print development per the Jobo instructions.

 

[Sirius Glass]

I have a Jobo CPP2 and I use "P" for the smaller thanks and "4" for the Expert Drums and large drums for print development per the Jobo instructions and The Rotary Processor Manual by John Tinsley.

I do not presoak for XTOL following Jobo's recommendations and The Rotary Processor Manual by John Tinsley. Everything else gets presoaked for the usual processing reasons and getting the film or paper for heat soaking [achieving the proper temperature].

 

[AlanC]

An important point which hasn't been raised so far is that if the film is vertical in a tank, you can let it sit for several minutes at a time without agitation and you don't get uneven development.
But if film is horizontal when being developed, eg sheet film in a tray, leaving it to sit without agitation leads to uneven development and a ruined sheet of film, at least in my experience.
So I always give constant, gentle, agitation to sheet film in a tray, but 35mm film in a tank gets one inversion every half minute.

Alan

 

[Photo Engineer]

Roll film in a tank on its side and with no agitation does yield poor results but sheet film in a tray does not necessarily yield poorer results.

Agitation improves uniformity, development (up to a point), and it can increase halide drag and fog.

Kodak made the drum processor for color film and paper and got good results with drums rotating in one direction. Jobo gets good results with oscillating rotation. There are rocker trays that get good results. The list goes on and on. The one idea is that the agitation should be uniform and suited to the film and developer (or paper).

Bad results are achieved through errors. Nothing more. Any method works, but the results vary as noted above and those are the criteria you must pick from as you optimize your work flow.

PE