I've recently purchased a Grafmatic holder. It seems to be in pretty good condition. All the septums are flat, the mechanism works smoothly and seats into my Crown Graphic easily. My question is what's a good procedure for testing how light tight the unit is.
Instead of wasting 6 sheets of film, I could cut 6 pieces of B & W paper to 4x5, insert into the septums and make a series of exposures in daylight, then develop. But what's the ASA to use for exposure? Is this a reasonable method for testing?
Thanks in advance.