I am using the Rockland Colliod tintype kit in conjunction with pinhole cameras. I am exposing the plates in daylight within the cameras (no negatives). The pinhole aperture is f239. I've found a million charts that convert typical aperture exposures to the pinhole exposure, however, I don't know the speed of the ag-plus emulsion or how to convert that to an exposure time. Hypothetically, if the speed of the ag-plus were 10 ASA would my exposure be twice that metered for 100 ASA? How would I figure out what the speed is? Also, I read on the website that i need to meter with blue acetate in front of the meter because the emulsion only reacts to blue light... how much will that increase my exposure time... does anyone know if i'm looking at a 1/2 hour exposure or a 1/2 day exposure? I'd appreciate any input, I'm desperate for help. Thanks.