Exposure Information

The following exposure information is a starting point. For a camera with a focal length of approximately 12 inches, and an aperture that is the diameter of a push pin at its largest size, (not the tip) and using black & white photographic printing paper for "film".
Bright Sun, Bright Subject: For the shortest exposure times work in sunlight, especially if you are using use black & white printing paper as your film. Although sunlight is not consistent from morning to evening, or season to season, and weather changes, it is a rich source of UV light. Photographing in deep shade or indoors increases the exposure times for paper negatives. An indoor exposure could require hours instead of minutes!

Test your Camera for Light-leaks: In the darkroom or using a changing bag, attach black & white printing paper in the rear of the camera. Close the camera body up, check to see your shutter tape is in place and set the camera in the sun for a few minutes without making an exposure. Develop the negative. If it is not pure white you probably have a light leak. Try applying another coat of paint to the interior of the camera, and check to see that that your lid fits securely. If you suspect a leak tape the outside. If it leaks around the lid, tape the edge of the lid and repeat the test. Make sure that you camera is light-tight before going on to the next step - making an exposure.

First Exposures: Place the camera on the ground or somewhere stable. If the camera moves during the exposure your photograph will be blurry. Remove the tape for 30 seconds (bright sun, bright subject). Return to the darkroom and develop the paper negative. The beauty of working with black & white printing paper is that you can develop by examination and quickly fine-tune the exposure time. If your negative develops too rapidly (gets dark too quickly), shorten the next exposure. If the negative is too light, increase the exposure time. Remember that if you want the negative twice as dark, double the exposure time. With some trial and error you will discover what the correct exposure is for a particular camera. If there is no image at all, check if your aperture hole to see if it is plugged with black paint.


Self-Portrait with Umbrella, '83

paper negative
positive print

The exposure for the negative (above left) was approximately 45 seconds in bright sunlight. I set the camera down on the ground, removed the shutter tape and walked into position. Fifteen seconds into the exposure I slowly opened the umbrella. At the end of the 45 seconds, I replaced the shutter tape.

Using Paper Negatives: Generally, black & white printing paper is not panchromatic (sensitive to all colors of the visible spectrum). In the example above you see that the foreground and plants are underexposed. Skies will over-expose and loose cloud details due to the paper being more sensitive to blue light.To print a positive image, you can contact print the negative.