> On Thu, 11 Jun 1998, Judy Seigel wrote:
> > Also, with the sunlamp bulb I began with, even at 30 inches,
> > exposure was very uneven. Edge falloff was horrendous.
>
> Hmmm, I haven't seen that, but would guess that it probably depends on
> the height of the bulb and the size of the print. I tried one 8x10 gum
> print the other day with the lamp 24 inches above the frame. Didn't
> notice any edge fall off, but will have to check.
I hadn't *noticed* it either, but in a fit of anxiety one day (really so
much testing must, ultimately, be from anxiety) I put five of my set of
nine identical 4x5 negatives (that was before the reign of the 21-step) in
the 4 corners and center of the print stage, covering an area slightly
larger than an 11x14 inch print -- at a height of THIRTY inches! The
corner prints were *dramatically* lighter than the center print. I did not
use the bulb again.
Other drawbacks of sunlamp: a lot of electricity. You can light 6
blacklight fluorescents for only 120 watts, less than half, without heat.
Fluorescents also last something like 9000 hours: My fleamarket sunlamp
bulb was rated for only 25 hours. Then you were supposed to wait 5
minutes before turning it on again -- and you could *really* get a
sunburn. Etc.
> Interesting thing is that I tried making a carbon print this last weekend
> using bright sunlight, and got a really nice print at an exposure of 1.5
> minutes. Using the same tissue with the sunlamp seems to give a much less
> contrasty image, and takes between 30 to 45 minutes to expose. Looks like
> I'll need to go to a different light source.
We ran a thread a couple of years ago when (as I recall) Sam Wang and
Sandy King tested the difference in contrast from different light sources
for carbon. They tested daylight fluorescents (which Phil Davis used) vs.
blacklight fluorescents, that had been the norm til then. They found
(this from memory) they got a contrast they liked better with the daylight
bulbs, bought for $3 each at -- whatever nice source you have in the
HEARTLAND that we lack here in tourist-ville, where my local hardware
store, wedged between a sidewalk cafe and a custom leather shop, charges
$7 apiece for fluorescents...
I did some tests at the same time on the daylight vs. blacklight
fluorescents for cyanotype and gum. Cyanotype simply would not expose.
Gum did expose, times were at least 3 times as long, and scale much
shorter -- but colors more intense (differences I refer to in passing in
my gum intro article). This is one of the tests still on the docket for
"soon as possible." I thought it would be great to be able to change gum
contrast by simply changing a set of bulbs, also thought of possibly
alternating bulbs, for possibly the best of both worlds...
> Well ... it was intended to be complimentary. I'm guessing you'd rather
> it be called a journal ... ?
We used to have an expression I never got the meaning of, "call me
anything but late for breakfast." (Maybe some other phrase collector can
explain?) So.... anything but *newsletter*....;- ) For 15 years I edited
the world's most obscure artists' publication which, nevertheless, WE
thought of as a magazine, or quarterly. We never did get people to stop
calling it newsletter. But rest assured, we never held it against them
(much).
cheers,
Judy