Re: sun exposures vs. UV light

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From: Les Newcomer (lnphoto@ismi.net)
Date: 06/17/00-01:32:45 PM Z


I don't know if this works with VDB but when I printed with studio proof paper I
got my best results by exposing to the northern sky and not directly in the
sun. Just a thought.

Les

Sarah Van Keuren wrote:

> I have sun-printed in vandyke from an unairconditioned studio in a suburb of
> Philadelphia and at summer workshops in other humid places with good
> results. It sounds to me as if you may have overexposed your prints. If the
> coated paper was too moist when exposed you would have gotten gray tones,
> not warm browns.
>
> If you happen to have noted the exposure time for a good print from a
> particular negative in the artificial UV light that is no longer available
> to you, try comparing it with test strips from that negative in full sun
> (and also in overcast?), and see what the ratio is. You might find the best
> sun exposure is half the time or less of the artificial light exposure.
>
> With practice you can learn to sense the intensity of the light as if you
> were a light meter yourself, becoming conscious of how much your pupils are
> contracting, for instance, and the difference in sensation on your skin as
> the sun goes behind a cloud and then comes out again. It is important to
> slow down enough to sit with your print for the half minute or so needed to
> expose it to feel the light.
>
> Sarah Van Keuren
>
> > I have a few questions regarding sun exposure as opposed to an artificial
> > UV light source. I've been using an excellent UV light source at the school
> > where I teach. Now, however, the powers that be have rearranged studio
> > spaces, leaving my equipment in storage for the summer. So, now I'm trying
> > to move my operation home and use sunlight for exposure of Van Dyke prints
> > or cyanotype prints. I've always had a controlled environment in which to
> > work, so having the number of variables increased has me wondering what to
> > try next.
> >
> > My initial tests with sunlight VDB were hideous! The highlight steps of the
> > step wedge had yellow stain, the entire print had a much warmer, reddish
> > color, and the contrast was very low. My prints are usually a rich, dark
> > chocolate color (on Stonehenge) with nice cool white highlight. Could the
> > differences in light sources have cause the color difference....or is it
> > more likely to be caused by the other changes in environment (temperture,
> > humidity, water).
> >
> > I live in the Missouri Ozarks where it's extremely humid and often very
> > hot. The rooms I'm using to coat and dry the papers are not air
> > conditioned. I have the opportunity to move to another air conditioned
> > darkroom for coating and developing, but would need to use sun exposure.
> > Does anyone have recommendations for my next tests or experience with
> > various humidity levels?
> >
> > Thanks,
> > Gwen
> >
> >
> >


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