[Alt-photo] Split exposure of cyanotype

John Isner john.isner at gmail.com
Sun Jan 28 22:18:56 UTC 2018

I am relatively new at alt process in general and cyanotype in particular.
I'm using Ware's formula on Cranes Cover 90 lb Wove, exposing in the sun
with a UV integrator meter, and following all of the instructions that came
with the New Cyanotype kit.   I also carefully followed the steps in Ron
Reeder's chapter of Christina Anderson's Gum book to determine exposure
time for maximum black, the optimal negative density, and a curve for
correcting the midtones.

On page 183 of Christopher James' 3rd edition, James suggests that you can
get improved shadow detail by suspending exposure midway through, keeping
the print in the dark for 15-30 minutes, then returning to UV for the
remainder of the exposure.  I found that this technique definitely improves
shadow detail.  James also says you should not "lose D-max integrity" but I
did not find this to be the case.  My overall print seemed lighter.  The
borders, where the paper is fully exposed to UV, are somewhat lighter than
the borders of a print made in one go.

If a split exposure is supposed to retain D-max integrity, then I'm
guessing a longer exposure is needed.  If so, do I need to make a separate
determination of exposure time under split exposure conditions?  Or is
something else going on here?

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