Jarin Blaschke
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D-96 is designed to produce lower than normal contrast, a gamma of 0.55 rather than 0.68. This is done because the negative film is printed on high contrast stock. Instead of trying to change things stay with the system that was developed.
Rodinal is intended as a single shot not as a replenished developer. Why not use a developer designed for use in automatic processors.
D-96 is designed to produce lower than normal contrast, a gamma of 0.55 rather than 0.68. This is done because the negative film is printed on high contrast stock. Instead of trying to change things stay with the system that was developed.
Another route possibly worth exploring: the metaborate buffered developers like DK-50, DK-60a - they've got a low enough sulphite content (30g/l in DK-50) to be non solvent, they're replenishable as designed, and (speaking very, very generally) they tend not to shoulder as readily as D-76 etc & tend to give more of an upswept curve. Might be worth a try/ look. Geoffrey Crawley published a modification of DK-50 for use as a one shot high sharpness developer which might also give some jumping off points for modifying the formula for greater sharpness.
If you're really determined to do something with Rodinal, Mirko at Adox/ Fotoimpex might be a useful person to ask - given that Adox now makes the official Rodinal "together with former Agfa scientists", there might be someone at Adox able to give a clear answer on the viability of making a replenishable developer that behaves like Rodinal.
Thanks. If Rodinal didn't work out, I might try a metol-glycin developer (FX2). But first, there might be a possibility of getting a pyrocat variant to work, which is much closer to the ideal. Testing ahead....
What is Mirko's contact info? Maybe a Ordinal type could be replenished if it was activated by something other than hydroxide?
-Jarin
Unfortunately, what limits options is that a motion picture machine does not start development of all the film at the some time, but rather runs the thread of film through all the solutions, so the start of the roll is already being washed as the middle of the roll is just going into the developer. Therefore, a developer replenishment system seems to be necessary, as well as constant agitation. This system seems to preclude the possibility of a using tanning developer, which would have been my first choice by far. The oxidation products would keep accumulating.
Not sure however how well or easily a replenished system based on this could be achieved. Rodinal would be even more challenging I think - a full scale R&D job. Big issue is dealing with developer byproducts & their effects, which is probably why most replenished developers follow fairly similar designs.
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