Jeff, I'm fascinated by your report. Can you define "columnated light"
for a civilian? I've referred to sun as "that great point light source in
the sky," and I suspect there's some overlap in meaning, but I gather also
you're referring to some known concepts...A pre-existing technical
division?
A propos of your observations, when I first began cyanotype I experimented
with sunlamp (single bulb) vs. fluorescent tubes (blacklight). (Sun in
this city appears only on concrete & for the sole purpose of driving
lunatics over the edge.) My examination under a lupe suggested that the
single bulb image was more delicate and perfect. However there were so
many other drawbacks with that bulb (uneven light, heat, warm up period,
short life, great wattage & cost in electricity, etc. ) that I went with
the fluorescents. Your observations make me wonder what the difference is
-- wavelengths (I didn't know about wavelengths then) or collumnation.....
or?
> hours. Using the sun in Tampa in a real challenge. I make a small test
> exposure, then immediately precede with the working exposure. However,
> sometimes even this is not quick enough to avoid changing conditions. I
> do miss the results of the dry Arizona sun.
Have you ever considered foregoing test exposures? I find that with
sample prints on 21-steps (low, medium & high exposures), and reading the
negative (either by densitometer or by holes through cards on a light
table), I can usually do at least as well as by a test print -- in fact
since the sample prints are already aged, they may be more accurate.
Has anybody else tried this?
cheers,
Judy