From: Robert W. Schramm (schrammrus@hotmail.com)
Date: 04/16/00-08:12:15 PM Z
Gwen,
Last spring I ran some extensive tests on cyanotype and found that
using a sensitizer of 2 parts A to 1 part B gave the greatest
tonal range. I was using a 21 step tablet and controling everything.
When compared to the Ware process the results were nearly equal
although the Ware process did have a slight edge as to tonal range.
Your exposures sound about right to me. Of course a lot depends on the
negative density. The only way I know of to decrease the exposure
would be to use a stronger UV source. You might try using the sun.
Bob Schramm
>From: Gwen Walstrand <gwalstra@lib.drury.edu>
>Reply-To: alt-photo-process-l@sask.usask.ca
>To: alt-photo-process-l@usask.ca
>Subject: cyanotype sensitivity
>Date: Sat, 15 Apr 2000 17:39:18 +0100
>
>I am wondering what are typical exposure times for cyanotype and whether
>there's a way to speed up the sensitivity. Does the 2 parts A solution to 1
>part B solution give greater sensitivity as well as greater tonal range?
>
>I teach an alternative processes class that uses a 1500 watt metal halide
>plate burner (the very low end of the plate burner market, manual
>shutter...). The light source is placed about 30 inches from the vaccuum
>table for greater coverage. Our typical exposures for Van Dyke, Gumoil,
>Kwik Print and other processes are all between 4 and 8 minutes. Cy anotype
>exposures create quite a bottleneck in the classroom. Any suggestions for
>speeding up the exposure times?
>
>Thanks in advance,
>Gwen Walstrand
>
>
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