UV-exposure units/ UV LEDs: Cyanotype fogging problem solving

Hello all,

Colin, Richard's recommendation is an excellent one. Any book by Mike
Ware is worth getting and reading. Or if you are lucky enough to hear
him speak i urge you to do so. He is highly witty and very into the
process. He speaks and writes with a great clarity about photo/chemical
discovery. At the university of madison i managed to catch two
fantastic lectures that were part of a multi disciplinary show dealing
with iron and it's artistic properties.

Your highlight stains may be from "fogged" paper. If the paper has been
in a humid environment for too long it acts like a pre-exposure. I ran
into this problem at Jesseca Ferguson's pinhole workshop while learning
to hand apply emulsions. I traveled to Bennington, Vermont during
August and it was so humid that certain heavier printmaking papers
started developing as the coating dried on the surface. The humidity
was the cause. A side note I saw a floating mountain there. It was late
and fog filled the mountain valley leaving the neighboring mountaintop
floating above the moon lit "sea".

Back to reality sorry for digression. Fogging can also occur with older
coated papers if you purchased them ready made.

I use Crane's papers for much of my work now. And I seem to remember
Mike Ware using them as well for his work. I have also had success with
using some of the Lana mill papers, and some of Arches papers too. I
like papers that have a strong "hand" or crispness to them. This is
sometimes achieved with coatings or sizing inside the papers. And
sometimes the hand of the paper is increased with a process by which
the paper is passed through extra sets of rollers compressing the
paper's fibers into a tighter layer. I have had wonderful luck with
japanese papers with VDB (van dyke brown) processes too, but they are
almost ethereal in the trays/baths. But once dry these papers again are
easy to handle.

I have not tried to expose the papers through an enlarger. I would
think it is possible if you really have a dry darkroom and a high out
put UV light source, uncoated enlarger lenses, and a lot of time.

To print in northern wisconsin, I built an exposure unit from (12) 4
foot florescent light tube holders and a light switch. I ordered the UV
lamps that are not "purple" coated, instead they are like the ones
found in a tanning salon. I use contact printing for my work as you
have probably guessed. My exposure times with VDB run about 10 minutes
time. I use long selves and a face shield while the light is running.
You only have one set of eyes and I spent too many hours in the sun
already to risk too much extra exposure. You could try a trial
membership at a tanning salon and sneak in a few contact frames and a
bucket of water. You will find if you live in a large metro area after
a government skin cancer report "home tanning beds" sometimes are free
and are 6 to 8 feet long!!

Recently, i have been concentrating on the eccentricities of wet plate
collodion. While doing research on the process a fellow wet plate
practitioner found on ebay a LED flashlight which emitted UV band
light. He was able to expose the wet plate emulsion in near darkness!!
When i read that i began to turn over the idea of mounting a series of
LED UV bulbs in interior light fixtures for a still life or model.

I wonder if it would be possible to wire a group of these UV LED bulbs
into an old omega D2 enlarger and let er rip! The LED's wouldn't be as
hot as a point source mercury lamp, and a whole lot safer to have
running. This type of configuration may allow for enlargements from a
negative onto paper as well (I'm just guessing here).

Wow this is longer than i intended and hope this is of interest to
list. Any thoughts about the LED's would be of interest to me. I enjoy
the problem solving nature and the creativity of the pinhole community.

Respectfully,

eric nelson
artist/educator
chili, wisconsin, usa

On Nov 3, 2006, at 9:08 PM, Colin Talcroft wrote:

> I was wondering more how to keep it from going too
> dark, so the highlights don't turn blue. And, what are
> sources for cyanotype papers? Do you expose directly,
> or with negatives? Does the paper respond to enlarger
> light or only sunlight?
>
> Colin
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Received on Sat Nov 4 10:21:34 2006