From: Garet Denise (garet@rmi.net)
Date: 04/25/00-03:14:24 PM Z
Joe,
I remember from your tests of several months ago that perhaps there
was a clearing issue. The BL vs. Halogen light sources in your tests
are certainly printing differently, but I still wonder if it is more
than just a speed issue. Did you try different lengths of exposure?
Did you try clearing the BL prints longer? Perhaps the different
light source affects the clearing rate (pure speculation)? I seem to
remember you mentioned a 30 minute clearing bath. My prints sometimes
don't even start to clear within 30 minutes. Not that I would wish an
8 hour clearing time on anyone, but it works for me and my prints do
clear given enough time (yes, Judy, even with Joe's rabbit skin glue
size which I have been using because it clears better than others).
>Just a thought. Assume a layer of particles. Light striking straight
down
>would expose less just beneath the particle than a diffused source
which
>could angle around and expose under it.
>
>--Dick
>
This may have something to do with it also, particularly since you
used a yellow pigment, which should tend to absorb more of the
blue-ultraviolet waves than other pigments. The diffused source would
tend to cut in under the particles more, as Judy said. I'll also
second what Judy said about the time lag. I've coated two sheets at
once and exposed one up to 48 hours later with only a barely
perceptible decrease in clearing of the highlights (granted it was
cool weather and typical low Rocky Mountain humidity).
>Halogen lamps appear to print cleaner, with better separation and
>contrast with respect to the gum emulsion.
Odd, it seems that most of us are going for less contrast (longer
range) in a gum print. Or was this from a half-tone negative?
>I'll be testing more now that the current school semester is ending.
Good for us! As usual, we have only more questions, and all of us
wishing for someone else to do more testing.
Garet Denise
garet@rmi.net
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