From: Sandy King (sanking@clemson.edu)
Date: 07/13/02-02:52:43 PM Z
Judy Seigel wrote:
>
>When I tried grow lights for cyanotype, they were abysmal -- about 1 hour
>for what takes 3 minutes with BL (tho other types of grow light could be
>better).
>
>IME there's little if any advantage over BL in metal halide, except you
>get to use 1000-2000 watts of electricity instead of a puny 100 - 160, so
>you can run your air conditioner more... There may be somewhat more
>contrast, but for gum, which has so many controls in emulsion &
>development, etc., this seemed irrelevant.
>
>Judy
The so-called full spectrum lights are also pretty poor performers.
As for the comparison between MH and BL lights I use both in my work
with carbon and kallitype and find that although the differences
between the two lights are not really dramatic there are definitely
times when one light works better with a particular negative than the
other, and it is not just an issue of printing speed or contrast,
though that is often an issue as well.
However, it is my belief that most people who use a contact printing
frame instead of a vacuum frame will get sharper results about 90% of
the time with a semi-collimated light source such as the metal halide
than with a diffuse light source such as a bank of BL tubes.
Sandy King
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