Smieglitz@aol.com
Date: 11/13/01-06:22:43 PM Z
In a message dated 11/13/2001 17:52:52, sanking@clemson.edu wrote:
<<I have strong
supporting evidence from recent tests that several other processes
(carbon, gum, cyanotype, vandyke and traditional kallitype) have
significant sensitivity to light in the near ultraviolet and violet
between 400 and 475 nanometers.>>
Hi Sandy,
How are you measuring sensitivity? I ran a spectrosomethingorother on a
dichromate solution about 2 years ago (assuming absorption was indicative
of/equivalent to sensitivity) and found a secondary peak absorption spike
around 370nm which was pretty close to the maximum 365nm peak reported
elsewhere (Ware, etc., hmmm, should that be "elseWare") so I went with that
and tried to find a UV/light that output efficiently in that region. (I
further assumed any pigment would decrease the sensitivity.) However, the
spike was fairly narrow as I recall and the curve flatlined in the visible
with just a minor bump out around 600nm. By analogy, the curve looked like
far UV would be Everest, the near UV 370nm spike would be the Adirondacks and
the visible 600 bump would be Florida.
Joe
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