Re: UV lights for gum

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From: Christina Z. Anderson (tracez@mcn.net)
Date: 04/25/00-08:46:27 AM Z


Very true, Les, which is why I would suggest a comparison of the four
sources by the same person (probably impossible unless he/she is very rich
and possesses all light sources!) with the same substances at the same time;
that way you'd at least eliminate some of the variables that would give
false reads of the experiment, e.g. gum mixture, paper, person's negative,
humidity in the environment, pigment type, on and on. I have always
preferred the sun for two reasons only: I usually fly by the seat of my
pants in photography and prefer running inside and outside (with a cup of
coffee in hand) in an intuitive panic to expose my prints; and, I don't
possess another light source! The problem being, as you have pointed out,
that I get great sun in MT all the time but the angle of rays and strength
of the sun is so continuously changing that there is a time period I cannot
print, basically about november through feb. And, of course, how many of us
living in big cities actually have easily available sun? Therefore, I would
love to buy a light unit but now am in a quandary as to which one is best
for gum.
Chris

> The there's the variablity of the sun itself. Montana sun in June is
different
> from Montana sun in December which is still different than the sun that
hits
> the ground in LA. any time of the year. So anybody's empirical tests will
only
> be good for the surrounding area, will it not?
>
>
> Les
>
> "Christina Z. Anderson" wrote:
>
> > I am very interested in this strain: I have always printed my gums in
(lo
> > and behold) sunlight and they have worked out fine, and have heard that
> > artificial light sources in general produce duller images, but thought I
> > would buy an Edwards Lightbox in the near future because Montana's
sunlight
> > is pretty indirect in dead winter. So you are saying that fluorescent
(sp)
> > bulbs are duller and lower in contrast than two other artificial light
> > sources? How about the three artificial in relation to sunlight? It
seems
> > we are talking four sources here: fluorescent, quartz halogen, and
metal
> > halide....vs. sun, of course. So which is best? Or is this anecdotal?
In
> > other words, wouldn't you have to test the same neg 4 times to really
get a
> > good judge of the issue, for perhaps it's the neg that is the problem
(or
> > the gum mixture, etc)? Is there visual proof? Please excuse the
snipping
> > condensation of two messages below...
> > Chris
> >
> > > As a part of that first online class (kudos, Dick...great idea and
> > > > experience) I was a victim of the fluorescent failure. I'd used an
> > > > Edwards Engineering box successfully for some prints in V.D,
cyanotype
> > > > (original and Ware formulas), platinum, and gum. Of all of these gum
was
> > > > the worst.
> > > > During the Livick class, my test negative just died in all tests and
> > > > soon it became apparent the difference was the light source.
Subsequent
> > > > testing by another classmate, Joe Smeigel, with quartz halogen lamps
> > > > produced promising results, but the metal halide lamps were clear
> > > > winners.
> >
> > > As ever, generalisations about gum printing seem to beg for
contradiction.
> > > Or let me say again that recently when my NuArc died, I went back to
the
> > > BL bulbs and found they printed much better, easier. My thought is
that
> > > they print gum somewhat flatter -- ie, longer scale -- which could be
why.
> > > (Tho when I had the reflective foil under the fluorescent bulbs they
> > > printed worse, purely fuzzified.)
> > >
> > > >
> > >
> > >
>
>


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