Smieglitz@aol.com
Date: 06/20/01-10:22:32 AM Z
In a message dated 06/20/2001 7:43:16, Jeffrey D. Mathias wrote:
<<However my interest is with the spectral sensitivity of the Pt/Pd
coating. I have not see any information or research on the spectral
sensitivity of these or any of the other alt-processes. >>
A few quotes pulled from the archive regarding dichromate sensitivity follow.
I ran a spectral absorption test on a dichromate (K?) about a 1 1/2 years
ago which as I recall pretty much agreed with the following quotes. I've
since misplaced the specifics and will try to hunt them down.
Joe
>>hello all
I was reading a french very technical photographic book (glafkides) and find
this
interesting things in it about gum.
1.the sensibility of dichromate to light: max 210nm in far UV, fall to 325 nm
and
get to another max (but lower than the first)at 355 in near UV and fall again
to
580 nm in the yellow green
the best photographic rays is between 355 and 425 where the sensitive curve
is the
more straight.
Nze Christian<<
>> Dichromated colloids have their greatest sensitivity at about 210
nanometers and are considered totally insensitive above 600 nanometers.
However, glass absorbs virtually all of the radiation below 300 nanometers,
and the actual practical sensitivity has been found to be between 350 and
450 nanometers, with a maximum at 360 nanometers. Within this range it will
be found that contrast will range from a minimum at 350 nanometers to a
maximum at 450 nanometers.
Sandy King<<
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