Problem developing 4x5 sheets in Jobo processor : LUSENET : Large format photography : One Thread

Not long ago I bought a Jobo CPA-2 processor and have been developing 4x5 sheets in the 2500 series drum. Recently, I have had problems with undeveloped "blotches", especially near the edges of the film. Some of these can be quite large. Does anybody know what these are from? I suspect they may be from air bubbles. I am using sufficient chemistry .

-- Tom Hieb (, July 31, 1998


If you are processing more than 4 sheets at a time the film may be touching, keeping the chemistry from it. I know they used to have this problem and recommended only 4 sheets at a time. Since switching to the bigger 6 shooter style drum I have never had the problem again. Try again with 4 sheets or if less, a space between two on the same section of the reel and see if that doesn't solve the problem.

-- Dan Smith (, August 01, 1998.

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