an excellent start Toffle,
some questions if i may;
what maths did you use to determine 5hrs?
why .75mm? what maths?
given that f stop equals distance from pinhole to light sensitive material (focal length) divided by diameter of pinhole, what dimensions and maths?
Ray
Tom,
If you get it to work, perhaps you would like to find out about the "pellet process" form of cyanotype - it gives a positive image instead the usual negative image.
Just google "pellet process"
Regards,
Neil.
sounds great. i love shooting pinholes. one suggestion. why not use a 6 inch box? you would get an f stop of about 330. that may reduce your exposure times. i shoot 8x10 with this set up and it is a good FL.
keep us posted.
eddie
As far as I know, relatively few substances reflect UV, so you may be chasing the impossible here. What are you attempting to photograph?
For now, I have my setup in my backyard. (someplace I can leave it for several hours untouched.) The scene is flowers, trees, sand, and water. I was hoping that over the long (looong) exposure times necessary for cyanotype images there would be enough UV reflected to create a decent image. If I'm mistaken, all I've wasted is a few sheets of treated paper and a few hours sitting in my own backyard.
Cheers,
Sorry for doubleposting, but has anyone tried cyanotype rex?
This seems to be the answer to direct photography, since the improved versions will make it possible to use "regular" light spectrum & very quick exposure:
http://www.f295.org/Pinholeforum/forum/Blah.pl?b-apd/m-1137519426/
I'dd be happy with some skyline/landscape b/w contrast images
Also, I have read up a bit on anthotypes
( http://www.alternativephotography.com/articles/art098.html )
since it will be easier and more fromscratch if I do this with kids.
Some plants only need 1-3 hours of exposure, which is relativly low, I wonder what light spectrum does the trick- so maybee its more likely to use this in a pinhole camera thats steadily fixed to a high contrast landscape or skyline for example?
Since it is positive developing too, it would be ready to view instantly, only downside is that there seems to be no way to stop the exposure except for keeping it stored in a dark place...
I would like to point you all who are intended to make in-camera exposure using *any* cyanotype formula to the address I provide below :
Dead Link Removed
In short: Don't waste your time...
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