Re: sun vs. UV lights in cyanotype

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From: Christina Z. Anderson (zphoto@montana.net)
Date: 01/29/03-10:10:44 AM Z


Yes, Sandy,
     This is why I brought this up. I was always under the impression that
sun at a 90 degree angle to the contact frame would produce the sharpest,
nicely contrasty print. Uv would be more of a diffuse source of light. Now
that I have said James said this, I should perhaps clarify his quote: p.
109, "You can also achieve lower contrast appearance in your image by using
the sun as your UV source. Cyanotype exposed by sunlight tends to provide a
longer tonal range than does a mechanical UV light and thus creates a lower
contrast image by a light to dark association.". IT seems in essence he is
talking about apparent contrast, the tones relating to one another, a longer
tonal range equating with an apparent lower contrast. But still, it seems
fishy.
     However, you are saying, below, that the north sky produces greater
contrast??
Chris

----- Original Message -----
From: "Sandy King" <sanking@clemson.edu>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Wednesday, January 29, 2003 8:54 AM
Subject: Re: sun vs. UV lights in cyanotype

> If James really says that I think he is wrong. With all of the UV
> processes I have used the sun gives greater contrast than the UV box.
> But even with the sun there is a marked difference in contrast
> between exposures made in the shade (greatest contrast) with the
> contact printing frame pointed at the north sky, and those made with
> the frame pointed directly at the sun (less contrast, but sill more
> than with the UV box).
>
> Sandy King
>
>
>
> >Do those who do cyanotype regularly find the sun gives less contrast than
> >the UV box? Christopher James says this--that you get a longer tonal
range
> >in the sun and hence lower contrast.
> >Chris
>
>


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