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C41RA bleach one-shot
For the small amount of film I now process, I've switched from C41
to the C41RA process. The RA process uses faster bleach and fixer solutions, for a total process time of about 8 minutes. I am using the solutions one-shot in a Jobo. The "RA" bleach is extremely expensive (though the Trebla version is slightly cheaper than the Kodak). This is probably because its replenishment rate is 1/10 that of the standard Flexicolor Bleach III (5ml per roll rather than 52ml). In fact, the replenishment rate is so low it approximates the amount of solution lost by carry-over into the fixer in a tank system, though it might not in a large dip-and-dunk. Kodak's process documentation does not give a one-shot capacity for the RA bleach or fixer -- it gives only the general advice that the capacity of bleach and fixer solutions used one-shot is twice that of the developer. I am sure the capacity of the RA bleach is not 10 times that of the standard bleach, but what is it? I know with small solution volumes capacity can have as much to do with build-up of byproducts and carry-over from the previous process step as with exhaustion, but I would hope I could, for example, reuse a tank of bleach at least twice, or use minimum volumes to cover the film with my (carefully-leveled) Jobo processor and tanks. By the replenishment rate (5ml per roll) both practices look like they should be just fine, but by Kodak's "twice the developer" instructions they are not. Opinions? I could call 800-242-2424, but I wonder if there is still anyone there who knows enough to help me when the written documentation can not. -- Thor Lancelot Simon "The liberties...lose much of their value whenever those who have greater private means are permitted to use their advantages to control the course of public debate." -John Rawls |
#2
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C41RA bleach one-shot
In article ,
sreenath wrote: I don't have any real answers to give, but I can suggest that if you are willing to mix the bleach from bulk chemicals, it could be really cheap. I am not aware of any publically disclosed formula for the rapid-access bleach, though manufacturers like Trebla seem to have cloned it. Are you? -- Thor Lancelot Simon "We cannot usually in social life pursue a single value or a single moral aim, untroubled by the need to compromise with others." - H.L.A. Hart |
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