I've been helping a friend of mine build a 12 foot square room out in the desert to be a camera obscure as the final project. The house is facing another house that is run down. We're almost done building it but I need some information on pinhole size and material. I've built camera obscuras before and pinhole cameras and generally use soda can metal to make my pinholes out of. However, for his application, the aperture is going to need to be like half an inch in diameter? What would be the best material for him to use? I would think it would be a little difficult making a larger hole in something as thin and flexible as soda can metal. I know that the thinner the material is, the better the image quality, and of course the less reflective it is the better. Also, seeing as he is showing the house on Saturday, the material needs to be readily available at home depot, or a hobby shop,...etc. Any information would be greatly appreciated!