[LargeFormat] Processing 4X5 recommandations.
Paul and Paula Butzi
largeformat@f32.net
Sun Dec 30 13:46:05 2001
> About the Jobo drum processing, I have a few questions to ask....maybe some
> of you may help me.
>
> What is the difference between magnet and cog drums?
Magnet drums have a magnet in the base; this magnet forms half of a
magnetic pair that attaches the drum to the drive in the processor.
Cog drums have a geared cog attached to the mouth end of the drum;
the cog attaches to an accessory on the Jobo processor called a 'Lift';
the rotation of the drum is driven by a gear on the lift.
If you get a Jobo processor, you definitely want a life, and you can't
use the magnet drive. However, all Jobo drums can be fitted with cogs,
and the cogs are pretty cheap (a few bucks).
>
> Since you put less fluid in the tank do you have to rotate them constantly?
The drums always rotate continuously on a Jobo. About every two rotations the
direction of rotation flips.
>
> At what speed do the drum usually roll in the processor. 1 rpm???
The drums rotate at about 40rpm. On the Cpp-2 I use, it's continously
variable from about 25rpm to perhaps 80rpm or so. Changing the speed
doesn't really seem to make much different when running film, although I've
heard it can make a difference when running Ilfochrome.
> And do
> they roll constantly?
Yes.
>
> Are the film spool sold separately?? Or are they include with the drum?
Film reels are sold separately, yes.
-Paul
web site at www.butzi.net