The most interesting but certainly the slowest method for using blueprint paper in photography is to directly expose the paper in a camera. While it’s a very simple method, it produces some of the most unique images, images that really show off blueprint paper’s unique qualities. The downside is that an exposure can take over four hours to complete, so a lot of patience is required when experimenting. If you don’t have the patience, move on to trying contact prints, but please give this method a try at least once.

To use a camera, simply cut your paper to size and insert the paper into the bac k of the camera where film would go. Make sure you do this under your safelight. If you have a film plate in the back, I suggest affixing the paper to the plate. Small bits of masking tape on the back of the paper work well, as do photo corners from a craft store or photo shop. Close up the camera.

Affix the camera to a tripod or find a very stable place for it to rest when making the shot. Attach the remote release cable and make sure that it’s set to lock when pressed.

Go outside on a bright and sunny day, preferably around 9 or 10 AM. Compose your shot, set the camera shutter to B or whatever is required to keep the shutter open, and open the shutter using your remote release. Make sure that the release locks with the shuttter open.

After four to six hours (depending on the light, your camera, and your paper), close the shutter and bring the camera inside. Under your safelight, remove the paper and put develop it (see the developer listing under equipment for details). When it is done, you’ll have your image!

Finding the right exposure time and light requirements for your camera and paper will take some experimentation. My Polaroid 95A takes about 4 hours on a nice sunny day for a good image, and my view camera takes about 8 hours of good sun for an acceptable image. You may find that you need to leave your camera in place and expose it over two days to get enough light. Again, look for a large aperture (f/2.0 is a good goal, larger if you can find it) lens on the camera. Much of the time, you’ll just use f/5.6 or even f/8, but you will want the larger aperture option for faster shots.