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If you choose to use photographic paper, you can load it into your camera under specific lighting conditions. For photographic paper, you have to load it either under a safelight, or a flashlight filtered through at least three layers of red cellophane attached to the lighted end. The flashlight must be six to eight feet away, so hanging it from a ceiling and working underneath it is a good way to accomplish this distance. Unlike photographic paper, film must be loaded under completely dark conditions. Practice loading your camera with a simple piece of paper in lighted conditions, and then with your eyes closed to get the feel of loading the film before you attempt to do so in complete darkness. You will have to cut the film down into smaller frames. The size of the frame will depend on the overall size of your camera's body. For most moderately-sized cans, you can use a strip of film cut into 2 3/8 to 3 1/2-inch pieces. For a camera made from a one-gallon paint can, cut a 4 by 5-inch piece of film. A camera made from a 2-pound coffee can will take a 2 1/4 by 3 1/4-inch piece of film. These measurements apply to the use of photographic paper as well. Use sheet film if possible, which is easier to manipulate as it is completely flat. Make sure to cut down your paper or film in complete darkness. A closet should work fine as long as no cracks allow light to seep through. If you are unsure about the ratio between the size of your film and the size of the camera body, err on the side of cutting too large of a strip of light-sensitive material. You can always trim down the edges of your photo after you develop it.
Choose photographic paper or film. Determine the size of your light-sensitive material.