BTTB DEVELOP SAME FILM OVER AND OVER AGAIN TO GET MORE FILM SPEED.

Camerashy

Camerashy

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There is a guy over on flikr that uses an improved version of Barry Thorntons2 Bath. Rudiger Hartung develops APX 100 at iso1250 in BTTB, he develops the film four times before fixing it.
BathA 4mins 30 secs Bath B 4mi s 30 secs
First cycle
4' 30" A then 4' 30" B, water stop, full wash
Repeat x4 wash and fix.

Can you only do this with a 2 Bath developer?
 
I suspect this is the way you have to go with 2-bath setups if you want to push film, because they don't necessarily respond to leaving the film in longer like normal developers do (i.e each step is done to completion). So in effect is this not just the same as giving a film a huge increase in development time and hence getting a roughly 3-4 stop push?
 
Dave_P said:
I suspect this is the way you have to go with 2-bath setups if you want to push film, because they don't necessarily respond to leaving the film in longer like normal developers do (i.e each step is done to completion). So in effect is this not just the same as giving a film a huge increase in development time and hence getting a roughly 3-4 stop push?
Click to expand...
18m in Bath A and 18m in bath B is it the same as doing x4 4m 30" cycles? That would be an interesting experiment. I wonder if you would just block up the shadow details and blow out the highlights. Rudiger's photos look OK but I have no idea if they have been digitally manipulated.
 
The time in bath A has to be long enough for the developing agents to diffuse into the emulsion, their will be a point of equilibrium where the emulsion has absorbed a level where any further absorption will be balanced by diffusion out of the emulsion.

So no, increasing the time in Part A will gave no effect once that balance point is reached. A more concentrated Part A would be one option, this would be similar to repeating the cycle. You would just increase the amount of Metol in Part A, leave the Sulphite the same.

Ian
 
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