Pyrocat-HD grain at 2:2:100 dilutions

[Tom Kershaw]

Due to suspicions of excessive (and variable) oxidization when processing 400 speed film in Pyrocat-HD in the Jobo @ 50 r.p.m. (i.e. longer development times), I've begun experimenting with using a dilution of 20ml A + 20ml B + 960ml water, and then using shorter process times. e.g. 7 minutes @ 26ºC for TMY-2. I have my suspicions that levels of grain are higher than should be expected considering one successful attempt at using the 1:1:100 dilution with TMY-2 yielded impressively fine grain on a 9x12" from a 35mm negative.

Any comments on grain and dilution?

Tom

 

[TimVermont]

When I switched from the larger 2500 series tanks on the lift to using the smaller 1500 series tanks with the magnetic drive and a nearly full tank, the level of film base stain dropped back to what I considered acceptable using the slowest speed on my JoBo. A squirt of nitrogen or other covering gas may help as well. While the lift is convenient, air is the enemy.

 

[sanking]

Due to suspicions of excessive (and variable) oxidization when processing 400 speed film in Pyrocat-HD in the Jobo @ 50 r.p.m. (i.e. longer development times), I've begun experimenting with using a dilution of 20ml A + 20ml B + 960ml water, and then using shorter process times. e.g. 7 minutes @ 26ºC for TMY-2. I have my suspicions that levels of grain are higher than should be expected considering one successful attempt at using the 1:1:100 dilution with TMY-2 yielded impressively fine grain on a 9x12" from a 35mm negative.

Any comments on grain and dilution?

Tom

I have not observed any discernible difference in grain between the 1+1+100 dilution and the 2+2+100 dilution when developing with continuous agitation in BTZS type tubes with continuous agitation or in drums with slow RPM on motor bases.

My advice would be to slow down the rotation speed of the Jobo, and if that is not possible try a dilution of 2+1+100. Both methods will reduce oxidation.

Sandy King

 

[Tom Kershaw]

My advice would be to slow down the rotation speed of the Jobo, and if that is not possible try a dilution of 2+1+100. Both methods will reduce oxidation.

Sandy King

To what extent should reduced rotation and dilution change to unequal proportions of A and B solutions affect development times?

Tom