JOBO processing - B&W rotation speed?greenspun.com : LUSENET : Large format photography : One Thread
I have a JOBO 3010 and the literature nor corporate web page had specifics as to rotation speed by hand. I have the roller base, but must manually spin this for the TMax 100 processing duration. one reference did site 50rpm (speed setting 4), which might get tiresome after 8-10 minutes. not to mention consistency of rotation.
easier than it seems?
thank you ..
-- Daniel Taylor (firstname.lastname@example.org), December 02, 1999
Daniel i use the 3006 affectionately referd to as the six shooter, which i use with a bessler (old)motor base. however prior to this i used to load one sheet of film into a kinderman 120 tank. no lid of course and about 1/2 inch of film sticks out. in toal darkness i rotated this tank with it's film sticking out,(in a solution of D-76) by hand at about one rotation every one and half seconds. the results were so good i really had to force myself to spend the money for the jobo drum. about rotation speed, i called the jobo rep and ask about such things as time and why should i spend the money for a jobo processer when my, by hand method and jobo on the motor base (32rpm) worked so well. surpprisingly enough he did not try to sell me anything, he said that thier working with 70rpm and auto reverse which seems to create the desired effect. he said a most important feature of the jobo tank system weather used in a processor or by hand is a 5 minute presoak in water, as i recall this is supposed to counter some of the disadvantages incurred with a jobo tank. the other feature of the motor base and expensive jobo processor is auto reverse which i belive happen at two? second intervals. so i would suggest based on my tests that you could choose a by hand speed that wont wear your arm out and as long as you are consistant with the rotation you may get the desired results. hope this helps. look in the the older files under processing their are some discussions there that are more techinal. j
-- richard hill (email@example.com), December 02, 1999.
I manually rotate a six-shooter JOBO drum at about 40 rpm without the roller base. It's a lot of exercise for your Popeye muscles, but there's nothing else wrong with it.
Coming up with a rotation speed is simple: how long do you wish your film to be out of the drink?
-- John O'Connell (firstname.lastname@example.org), December 07, 1999.