Maybe I'm reading this wrong, but it sounds as if you are removing the paper and scanning straight away with no development steps or chemicals? If that's the case, then the light from outside the pinhole camera and certainly the light from the scanner would be overexposing the paper, fading any image on it. What you might be asking for is just the normal steps for developing prints. First random link from google, here, is about pinholes using beer cans and photo paper. Some steps listed there. Heaps more info out there, no doubt people here have done printing and can add advice. What you want to be doing, I think, is; 1. Load camera in darkroom, maybe try using the darkest room in your house at night. 2. Take photo, given the length of exposure is 6 months, check with a pinhole exposure calc that you are not using too long a time. 3. Unload in darkroom, as in step 1. 4. Develop paper with chemicals, needs darkroom. 5. Dry paper, then scan. Also, sound like quite an interesting experiment. If you do get images be sure to post them up.