Re: Iron Processes with Dichromate - calibrating curves

I have been using dichromate to control contrast with kallitype for
several years, and have been doing the same with palladium for about a
year. I can not tell you the answer to your question as to exactly how
dichromate works in this process but I can give you a suggestion as to how
to use.

First, prepare a 5% stock solution of dichroimate. I use potassium but
ammonium or sodium would also work, though not with the same calibration.
Then, add dichromate to your developer as below to change contast
according to the DR of your negative.

DR 1.80 1ml of 5% dichromate per liter of developer
DR 1.65 2ml of 5% dichromte per liter
DR 1.50 4ml of 5% dichroimate per liter
DR 1.35

> I have a few questions for the experts out there pertaining to the use of
> K dichromate in iron process developers, i.e. Kallitype process. How
> exactly does the dichromate act to increase contrast on the print? Is
> Dichromate itself consumed (reduced) during the process of development by
> oxidizing out the iron? I'm curious about this because I'd like to try
> calibrating a negative correction curve with K Dichromate in the developer
> and am not sure how to proceed.
>
> Shall I assume that K Dichromate is being consumed in the process at
> roughly the same rate that as the replenishment with fresh developer? So
> therefore I should begin with developer that has no dichromate, but with a
> starting replenish charge of developer contining the K Dichromate?
>
> Michael Klemmer
>
Received on Sun Jan 9 10:27:59 2005