From: pete (temperaprint@blueyonder.co.uk)
Date: 11/14/01-06:56:01 AM Z
on 13/11/01 10:45 pm, Sandy King at sanking@clemson.edu wrote:
> Jeffrey Mathias wrote:
>
>>
>> Do keep in mind that a Pt/Pd coating is sensitive to more than just UV
>> light. I have not found any information on the spectral sensitivity of
>> Pt/Pd coatings. Nor have I found any qualitative information as to how
>> the final print may be influenced by various spectrums of light used for
>> exposure. This information is of interest, but I do not have the
>> equipment for such studies at this time.
>>
>> --
>> Jeffrey D. Mathias
>> http://home.att.net/~jeffrey.d.mathias/
>
>
> I am really surprised that there is no information on the spectral
> sensitivity of Pt/Pd coatings. Like you I have been unable to find
> anything on the subject.
>
> There appear to be no doubt but that your observation, i.e. that
> Pt/Pd coatings are sensitive to more than just UV light, is correct.
> Quite a number of platinum printers have reported faster printing
> times with Super Actinic tubes than BL, and the SA, which peaks at
> 420nm, emits virtually nothing below 380nm, and very little in the UV
> range, generally considered to be at 400nm and below.
>
> However, this may be true also for other processes. 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. I find this interesting because it
> suggests there is a band of considerable sensitivity for these
> processes of over 125 nanometers.
>
> Sandy King
>
>
>
>
>
Sandy a few years ago I was talking to a Guru at Starna Lighting a firm in
East London, who specialise in scientific and technical light sources he
stated that all the the photopolymar systems they worked with were most
sensitive at or near 440 nanometers. This seems to be in line with your
obsvations
--
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