Uneven development is *usually* caused by insufficient chemistry volume, an improperly levelled tank, or some sort of chemical contamination - holdover from color developer to bleach fix. If I remember correctly -- this is always a gamble -- you have a CP2 - and from the above, are using the magnetic coupling - somewhat more awkward than having the lift ... but not a great deal worse.Originally Posted by Adrian Twiss
Much depends on film size - with 35mm and 120, "P" rotational speed (I have the older model thus labeled) is used - that is about midway along the scale. The rotation pattern should be two (2) turns clockwise, reverse, two (2) turns counterclockwise, reverse, and continue - for all films except 110, which is rotated in one direction only. I'm not sure about the rotation speed for 5" x 4" film - I'd have to look it up. A "too slow" speed could possibly result in uneven development.
Much has been written about continuos agitation requiring decreased development times - I've already struggled with that idea ... and I've come to the point where I ignore it entirely for C-41 and E-6 development and use the published data. In black and white processing, I "wring out" the film developer-combination anyway and use my own time/temperature, which, incidentally, haven't been that far from the published data - yet.
If memory serves, manuals for the CP2, CPP2 and most of the other JOBO equipment are available on-line at their web site.