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

Re: question of gum bichromate spectral sensitivity

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