U of S | Mailing List Archive | alt-photo-process-l | Re: question of gum bichromate spectral sensitivity

Re: question of gum bichromate spectral sensitivity

  • To: alt-photo-process-l@usask.ca
  • Subject: Re: question of gum bichromate spectral sensitivity
  • From: Keith Gerling <keith.gerling@gmail.com>
  • Date: Fri, 12 Jun 2009 09:11:09 -0500
  • Comments: "alt-photo-process mailing list"
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No, they are not the same.  I have no meter that can measure such a bright light, so it is difficult for me to ascertain what the differences are, but my NuArc times are much shorter than my Violux times.  The bulb is farther from the image, so I think that is part of the problem.

2009/6/12 Loris Medici <mail@loris.medici.name>
Hi Keith,

If your contact printing frame or vacuum frame has ordinary glass, it will
cut most of UVB already. (>90% to be conservative... It's more like 98%
according to many web sources!) So, what you experience should be more
about the difference between the output of the lamps in regions other than
UVB, both in terms of spectral distribution and power. Are all
metal-halide bulbs the same?


11 Haziran 2009, Perşembe, 7:32 pm tarihinde, Keith Gerling yazmış:
> My Violux light source is much slower than my NuArc, although they both
> use
> metal-halide bulbs.  The Violux has safety glass that filters out light
> below 320nm.  Should I get faster results without this glass?
> Thanks
> Keith