I tried a few different styles in pinhole cameras, one shoe box, a bigger box and a oats box. All three are painted black in the inside and I used a dr pepper can to do the pinhole except the largest box which I wanted to try foil. They were all consistent but when I would develop the paper it would be gray with just the hole. At first I thought maybe the hole wasn't big enough to get an image but making the hole a bit larger didn't do anything. I know the photo paper was in correctly glossy side up. I've made a pinhole in the past but never had this problem.
Originally Posted by TheToadMen