Quote Originally Posted by jnanian View Post
you can alao stick paper in your camera leave rhe shutter open for between 20-to as long as you wanr.
the NecIphore's retina prints were made like this ... no chemistry needed ...
i have some i recently made vut can'postem yet, too far from my numeric electrification device ...

have fun !
john
What are those? I am guessing the exposure time gets so long it basically burns away the chemicals in the paper?

I have just done a proof of concept in camera cyanotype so will have a go with some fresh mix (just used some older coated paper I had done a while back), should yield a negative the DIY lenses I am making will be letting a lot of light in, one of the lenses I am building will be a 71mm f0.85, so they won't be slow lenses, just slow cyanotype paper!