From: Sandy King (sanking@hubcap.clemson.edu)
Date: 01/09/01-09:34:22 PM Z
Tox wrote:
>It looks like I should be able to goose one
>of my PMK kits with some EDTA and Ascorbic
>and get something *close* to the Rollo
>formulation. Since I can't effectively reduce
>the amount of bisulfite in the PMK concentrate,
>does anyone have suggestions on how much of
>each I should add? I'm assuming that if I
>use the levels from the Rollo formula with
>that much bisulfite in the mix that I'm likely
>to dissolve/complex part of the image.
You will have to do the figuring yourself to soup up your PMKmix but here
is what PMK and Rollo Pyro (ABC+) have in a liter of working solution.
PMK (1:1:100 dilution)
Pyrogallol 1.0g
Metol 0.1g
Sulfite 0.2g
Sodium metaborate 6.0g
Rollo Pyro (2:4:100)
Pyrogallol 3.0g
Metol 0.2g
Sulfite 0.2g
Ascorbic acid 0.1g
Sodium metaborate 12.0g
Potassium bromide 0.015g
EDTA 0.025g
Sulfite is the same in both formulas so that is not a problem. I am not
sure what would happen if you just added ascorbic acid. I suspect that it
would make the developer a lot more active but it *might* also reduce stain
if the amount of pyrogallol is not also increased. EDTA will not add any
energy to the developer
>
Instead of trying to soup it up you might just consider adding about a
pinch of sodium sulfite (dry) to each liter of working solution. That will
reduce oxidation and cut down on the heavy general stain/fog you get with
plain PMK in rotart processing. Your develpment times will be a little long
to get to the right density range for Pt./Pd. printing but that will give
you an opportunity to watch the Jobo in action and see your money at work.
Sandy King
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