I just built 4 pinhole cameras (an 8x10, a 4x5, and two Altoid 35mm). I used 35mm film to test the 8x10 and 4x5 cameras for light leaks and now I am ready to test them with sheet film. I have been able to find some reasonably priced 4x5 black and white sheet film but went into sticker shock when I priced the 8x10 film. In the past, my employer supplied all the sheet film I needed. Now I need my own source of reasonably priced 8x10 sheet film. Please advise.