From: Sandy King (sanking@CLEMSON.EDU)
Date: 01/29/03-11:44:56 AM Z
Chris,
I think you will find that exposures in the shade will at least 4X as
long as those made with the frame pointed toward direct sunlight,
perhaps even longer.
BTW, metal halide and mercury vapor exposing lamps print with about
the same contrast as outdoor exposures made in the shade.
I agree with your observation that making exposures with the sun is
an enjoyable process. However for reasons of consistency I tend to
use the artificial lights much more than the sun, and with most
processes I find that you can get the same results just by adjusting
the contrast of the negative. The one exception I have found to this
statement is POP processes, in particular salted paper printing. For
salted paper the sun, in my opinion, gives much better results than
artificial light sources, even metal halide and mercury vapor lamps.
And with salted paper I really do like the look you get when exposing
with the frame pointed directly at the sun. But of course you need a
really strong negative for salted paper, with a density range of at
least 2.2. With salted paper a negatives that takes 10-20 minutes to
print in direct sun may take as much as 4-8 hours to print with a UV
fluorescent bank.
Sandy King
>Thanks, Sandy, for this tip. Would you also say that your exposure this way
>(direct sun vs indirect) is twice as long, 4x as long, or what? I've just
>always done my exposures out on the back deck, facing the sun, which in MT
>is extremely strong (at 5000 feet elevation). However, the frame gets very
>hot. I now possess a UV lightbox, and find my Ware cyanos (dense negs) are
>taking about 16 minutes. I mean, I love doing them at all hours now that I
>have a light box, but the sun exposure was always such a more enjoyable
>process, running up and down the basement stairs and sitting outside while
>exposing and such. However, I have never thought to use the north sky.
>Chris
>----- Original Message -----
>From: "Sandy King" <sanking@clemson.edu>
>To: <alt-photo-process-l@sask.usask.ca>
>Sent: Wednesday, January 29, 2003 9:12 AM
>Subject: Re: sun vs. UV lights in cyanotype
>
>
>> Chris,
>>
>> With all processes I have used you get more contrast by exposing in
>> the shade with the frame pointed at the north sky than by exposing in
>> direct sun with the frame pointed directly toward the sun.
>>
>>
>> Sandy
>>
>>
>>
>>
>> >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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