From: Brigitte Harper (BHarper@glencore.co.uk)
Date: 11/23/00-08:48:12 AM Z
I once tried a cyanotype paper in a 4x5 6 inch focal length pinhole box, located
on a windowsill for 2 days.
I could not make out any image whatsoever upon developing. The final colour came
out as a sludgy grey and I wondered at the time whether under exposure, over
exposure or even reciprocity failure contributed to this. A second try with 4
days exposure brought the same results. That's when I gave up the idea.
Regards,
Brigitte.
|--------+----------------------->
| | Sarah Van |
| | Keuren |
| | <svk@steuber.|
| | com> |
| | |
| | 20/11/2000 |
| | 20:59 |
| | Please |
| | respond to |
| | alt-photo-pro|
| | cess-l |
| | |
|--------+----------------------->
>----------------------------------------------------------------------------|
| |
| To: Alt Photo <alt-photo-process-l@sask.usask.ca> |
| cc: (bcc: Brigitte Harper/london/glen) |
| Subject: cyanotype as negative |
>----------------------------------------------------------------------------|
> At 2000/11/20 02:21 PM +0100, Andre Fuhrman wrote:
>
>>As to using cy as recording material in a pinhole camera (the original
>>question): that strikes me fairly masochistic indeed. But then, why not?
>
> Why masochistic? Easy, very easy. You load the camera (can be a big box
> with a pinhole at the opposite end of the paper) put in on a support, and
> just let it sit in its position for (say) 12 hours! You don't have to sit
> with it!
>
> Fox-Talbot made his first negatives in that manner, with salted paper,
> though he did use specially made boxes and lenses. He just placed the boxes
> around his grounds and examined them once in a while until they look
> "cooked" to the right density.
>
>
> Sil Horwitz, FPSA
> Technical Editor, PSA Journal
> teched@psa-photo.org
> silh@earthlink.net
> Visit http://www.psa-photo.org/
> Personal page: http://home.earthlink.net/~silh/
>
But Sil, the difference between using a pinhole and a lens is considerable
and so is the difference between the time the old cyanotype takes and that
of a salted paper print. On printing-out-paper (about the same speed as
salted paper)in an oatmeal box and also in my 12" long 8x10 inch pinhole
camera, I was able to chart the paths of the sun across the sky over a few
days with no fogging of the paper. I wonder if those paths would have
registered on cyanotype. Perhaps, but that was direct sunlight coming
through the pinhole. On P.O.P. there was no rendition of reflected light,
not even the sky around the sun, no evidence of trees against sky. Maybe in
a very bright place with white buildings cyanotype in a pinhole camera would
register some sort of negative in the course of a few weeks. That's my
estimate after making cyanotypes for over 20 years.
But even if one could produce a cyanotype negative, it probably wouldn't work
very well since blue lets blue light through instead of holding it back and most
non-silver processes are sensitive to actinic light which includes blue
wavelength as well as ultra-violet. Am I wrong about this?
Sarah Van Keuren
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