Processing LF B&W Agitation ?greenspun.com : LUSENET : Large format photography : One Thread
The tank I have for LF use is a daylight type,not the kind with metal racks.My problem is how too agiatate, how much?Should I do this the same as I have done for years with smaller round 35mm/120 tanks?(Tipping & rotating at 30 sec intervals?)My film is T-Max 400,developer is HC 110 Dil. B.Kodak only offers instructions for tray dev.& and the raising & lowering with the rack type tank,(both done in the dark).
-- Edsel Adams (firstname.lastname@example.org), March 27, 2002
If I tank process, I use the jobo tank by hand. I've been getting even development using a tip-while-twisting motion, generally with three inversions at the head of each minute after continuous for the first minute. I also put a few drops of Edwal LFN wetting agent in with the presoak and the developer stages to reduce the likelihood of bubble marks (also "banging" the tank as with smaller formats). I reduced my development times by about 3-5% from tray development (30 seconds or so). I'm pretty happy with it.
-- Chris Jordan (Boston) (email@example.com), March 28, 2002.
Sorry to jump in... This is for Chris:
Saw your image "Winter Basin"...terrific!!!
-- Per Volquartz (firstname.lastname@example.org), March 28, 2002.
Do you have old the Nikkor 4x5 tank, in which each sheet of film spirals out from the center? The film is held in place by a band that wraps around the circumference of the film-holder. There are threads on this site regarding how to agitate for thas kind of 4x5 daylight developing tank.
-- neil poulsen (email@example.com), March 30, 2002.
I use the HC Combi Plan tank for 4x5, and although our film and developer combination is not the same, I don't see why the logic wouldn't be. When I asked a Kodak technician the same question several years ago, he assured me the small tank processing times I was used to from roll film processing would still apply, and my experience bears him out. Tray developing times assume constant or nearly constant agitation, and tank times tend to assume agitation on the minute. As long as you retain the agitation strategy you use with your own small tank processing, you should be fine. For me that's 5 seconds every 30 seconds. The design of the tank may affect how you agitate, but I find 5 quick inversions works well with TMAX 100 in D76 1:1. Retaining the same developing times regardless of format is a real convenience in the darkroom, I find. Hope that helps.
-- Stephen Longmire (firstname.lastname@example.org), March 30, 2002.
I use an old nikor 4x5 tank, and have started using it with constant agitation, and it seems to work well. I first tried rolling it in a tray full of water, but i decided that i uasualy keep the ambient temp around 70, so the water isnt necesary. Now i put the tank on a little machine with rollers meant for color print tubes, it works well.
-- jesse (email@example.com), April 02, 2002.