I've been experimenting a bit with ziatypes. It's a satisfying process, but I have one frustration with it--someone please tell me if I'm not thinking about this right.

Because every option of changing contrast seems to affect the color of the print, this process may be problematic if I'm interested in printing a series of images with the same tone--particularly if I want the most neutral tone, which also produces the least contrast. My impression is that I need to forget about adjusting contrast with the chemistry and just try to make sure the negatives match.

Alternatively, I could print the high contrast negs with one of the variants that produces warm tone/low contrast so that if I have a lower contrast negative I can increase contrast in the print while keeping a similar warm tone--but sacrificing the possibility of neutral tone images.

Am I thinking about this the right way?

thanks,

Robin Dreyer

If you are using ammonium dichromate to control the contrast then perhaps you are having humidity problems and you need to establish a humidification process that lets you control the humidity better. Ziatypes are very sensitive to the humidity of the paper as far as image color is concerned. I dry my paper completely after the coating has been allowed to soak into the paper. Then I put in a humidity chambers for a fixed time and when I take it out of the chamber I let it soak in a closed container to let the paper stabilize again for a fixed time. Then it is ready for exposure. This takes the current weather conditions and humidity out of the equation. This works well for me in getting consistent image colors.

Also if you negatives are underexposed you may not be achieving d-max. You can check this by including a step wedge in the print to make sure your exposure times are long enough. With black light tubes I have to have around eight minute exposures to get a good black.

David