Otherwise mind-boggling, inexplicable, random fogging from one gum print
to the next. I've never had a fogged gum print since I made the switch
to a quartz halogen FEL lamp (and more recently, a mercury lamp in the
NuArc). Before, maybe 1 out of 8 prints would become inexplicably
fogged, frustratingly perhaps at the third or fourth or Nth or final
layer.
In contrast to your experience, I don't believe the output of the (my)
tubes is constant nor predictable.
This observation of random fogging with UV tubes has been observed by
others including Stephen Livick and a few other individuals I have been
in contact with the past several years. Although I can't explain the
observation other than speculating about a nonconstant output, I repeat
that I have never lost a gum print to fogging or overexposure since I
switched lamp types so I've never looked back. Switching lamps abruptly
eliminated fogging for me.
Of course, I've dropped a few fragile wet prints or made some water drop
craters in the emulsion to compensate.
Joe
>>> zphoto@bellsouth.net 02/14/05 12:20 AM >>>
all my hundreds of gum prints are printed with UVBL (Edwards light
box)...5
minute exposures, perfect, predictable....but I do use only a 7% am di
in my
mix. What doesn't work for you, Joe?
Chris
> You don't say for which process(es) you intend to use the UV source.
> IME, UV fluorescents basically suck as an exposure source for gum
> bichromate but are fine for other processes. I would recomend a
quartz
> halogen, metal halide, or photoflood for printing gum.
Received on Mon Feb 14 06:28:54 2005
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