Here's my first tries. With a pinhole of known diameter at optimal distance
from the paper, ASA 3 will yield a good print at 20 minute exposure. At 7
minute exposure it looks like ASA (ISO)4 might be closer to the mark. Keep
in mind that using different ASA at different exposure time accomplishes the
same thing as using different multipliers for reciprocity failure at
different exposure times. You don't have to do both. Also, with positive
paper you have less exposure latitude than is the case for a paper negative,
because what you see is what you've got and there's no compensating when
making the print from a paper negative that's overexposed. If you make your
own pinholes, begin by assuming that you have an optimal "focal length" and
correct as needed. It's really fun to see a color print right out of the
camera. P30 chemicals and paper are available from Calumet. They can be used
at room temperature, so all you'ld need is a drum and roller.
