Re: Iron Processes with Dichromate - calibrating curves

Michae,
For Vandykes the dichoramate contrast control does not work, at least for me. In the developer (water) it increases the grain and doesn ´t move a centimeter in my step wedge. I have tried with various concentrations from 1% to 30% In the sensitizer there is no contrast increase also.
Jacques
  ----- Original Message -----
  From: Mike Klemmer
  To: alt-photo-process-l@usask.ca
  Sent: Saturday, January 08, 2005 3:10 PM
  Subject: Iron Processes with Dichromate - calibrating curves

  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 Sat Jan 8 16:39:03 2005