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C41RA bleach one-shot
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Thor Lancelot Simon
May 29, 2012, 6:34:30 PM5/29/12
to
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 t...@panix.com
"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
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 t...@panix.com
"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
sreenath
Jun 5, 2012, 10:10:13 AM6/5/12
to
are willing to mix the bleach from bulk chemicals, it could be really
cheap.
Search for message post by Bill Laut in rec.photo.darkrom where he
specifically provided details for using bleach one shot.
I hope to do color processing at home one day.......
-Sreenath
Thor Lancelot Simon
Jun 5, 2012, 12:06:43 PM6/5/12
to
In article <49507523-bc3d-4c48...@pr7g2000pbb.googlegroups.com>,
bleach, though manufacturers like Trebla seem to have cloned it. Are you?
"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
sreenath <sreen...@rocketmail.com> 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
>
>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.
bleach, though manufacturers like Trebla seem to have cloned it. Are you?
"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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