26. June 2007, 12:33 | by WD Milner | Full Article |

This article is a composite of several unknown sources and short notes and instructions from from my old photography workbook.

barn photograph Anyone can make a camera using common household materials that will produce pictures. Making and using a pinhole camera will acquaint you with the basic elements of photography while providing an inexpensive and interesting way to take pictures.

The photograph at the right was taken with a pinhole camera. The subject in bright sunlight, the pinhole size was .34mm (1/75 inch), the film-to-pinhole distance was 114 mm (4.5 inches) and the exposure was 2 seconds.

What is a Pinhole Camera?

A pinhole camera is a small, light-tight box or can with a black interior and a tiny hole in the center of one end. It can be designed to use either roll or sheet film. The two ends of the camera are parallel, and the end opposite the pinhole is flat so that the film is held in a flat plane. The pinhole has a cover (shutter) to prevent light from entering the camera when not taking a picture.

box type pinhole camera barn photograph

Box & Can type pinhole cameras.

Choosing a Can Or Box

When making a pinhole camera to accept roll or sheet film, you can use any light-tight box with tight seams or any can that has a tight-fitting top as the camera body. A 1 kilogram (2 pound) coffee can will make a good pinhole camera. You can also use a clean paint can, a vegetable shortening can, a peanut can, or even a cylindrical oatmeal box.

If the can chosen has a plastic lid, it should be painted black both inside and out. Before using it, check to make sure no paint has chipped off as chipped or peeling paint on the lid will allow light to enter the camera and ruin the photographs. To prevent light reflections, also paint the inside of the camera body with dull black paint or line it with black paper.

Making The Pinhole

Make the pinhole in the end opposite the removable end of the can or box as it is easier to attach the film to the removable end. While you can make the pinhole in the box or the can itself, it is much easier to make it in a separate piece of heavy black paper or thin metal which is then fastened over a larger hole cut in the center of the permanent end of the can or box. Heavy-duty aluminum foil, heavy craft paper or the backing paper from roll film can be used for this purpose.

needle detail With the pinhole 3 to 6 inches from the film, the best results are achieved if the pinhole is about .3 millimeters (1/75 inch) in diameter. An easy way to make a hole this size is by pushing a Number 10 sewing needle through the paper or metal to a point halfway up the needle. A smoother hole will result if you rotate the needle as you push it through. If using aluminum foil or paper, sandwich it between two lightweight cards while making the pinhole to ensure a smoother, rounder hole.

needle detail A good pinhole can also be made in soft aluminum sheet metal. Place the aluminum on a hard surface and make a small hole in the aluminum with an awl or an ice pick. The tip should just barely break through the surface. Typically, the hole will be a bit ragged so enlarge and smooth it by pushing a Number 10 needle into it from the indented side. Any rough edges can be smoothed with very fine sandpaper and then the hole opened with the tip of the needle. The same method can be used to make the pinhole directly in the metal of a can by working the hole through from inside the bottom of the can.

If the pinhole is made in a separate piece of black paper or metal, you should make a hole 6 millimeters (1/4 inch) or more in diameter in the center of one end of the camera body. The pinhole can then be taped in position over the center of the hole.

The roundness of the pinhole can be checked by looking through the back of the camera. To see if the image is clearly visible, aim the camera toward a printed page to determine if you can see the letters clearly.

Making The Shutter and Viewfinder

The shutter for the camera can simply be a flap of opaque dark paper hinged with a piece of tape. A small piece of tape can also be used to hold the shutter closed while not taking a photograph.

While not usually necessary, a viewfinder for a pinhole camera can be made of cardboard or wire. A larger frame should be located directly above the pinhole at the front of the camera and be slightly smaller than the film size used. If the film isn’t square, the viewfinder should have its longer dimension parallel to the longer dimension of the film. A smaller frame is a sighting peephole squarely behind the center of the large frame and directly above the film.

When aiming the camera at subjects closer than about 1.5 metres (5 feet), tip the camera up slightly to allow for parallax — the difference between the view you see through the viewfinder and the image recorded on the film caused by the separation between the viewfinder and the pinhole.

Loading The Pinhole Camera

The camera can be loaded with either film or fast photographic paper. Paper is easier to handle as it can be loaded into the camera under a safelight. If you don't have a safelight, a passable substitute can be made with a flashlight covered with several layers of red cellophane and located 2-3 metres (6-9 feet) away. Most film, however, must be handled in total darkness. The choice of film or paper may depend in part on the exposure times. Paper, because it is less sensitive to light than film, will likely require an exposure of about 2 minutes for sunlit subjects whereas film may require only 1 or 2 seconds for subjects in sunlight.

Depending on the size of the camera, you may have to trim the paper or film to fit. A camera made from a 4 litre (1 gallon) paint can will take a 4x5 inch piece of film or paper without trimming. A 1 kilogram coffee can will take a 2.25 x 3.25 inch piece of film or photographic paper. Other sized cans and boxes will use different sizes of film or paper.

Once you have determined the size of paper or film needed, tape it firmly to the inside of the end of the camera opposite the pinhole. The emulsion (shiny side for paper, usually the dull side for film) should face the pinhole. The emulsion on roll film is on the inside of the curl. Sheet film is identified by notches cut into one of the shorter sides. When you hold the film in a vertical position with the notches in the top edge toward the right side, the emulsion is facing you. Though not recommended, another way to determine the emulsion side of either paper or film is to touch both sides with a moistened finger. The emulsion side will feel slightly tacky.

You will need to tape down the four corners if you use cut-up roll film or paper as it tends to curl. Taping two diagonal corners will work for sheet film. Close the camera, making sure the shutter is closed.

Taking a Picture

To get clear, sharp pictures, the camera must be kept very still while the shutter is open. Once firmly secure, lift the black paper shutter to uncover the pinhole and keep the pinhole uncovered during exposures. Cover the pinhole with the black paper between exposures.

Exposure times can vary from 1-2 seconds for an ASA 400 film to 2 minutes for a bromide paper. A bit of experimentation will soon provide the best times to use for your camera in differeent light and film/paper combinations.

Processing and Printing

Print film negatives in the usual way. If you use paper to make your picture, make the camera exposure long enough to allow the resulting paper negative to be a little darker than an ordinary photographic print. Dry the paper negative and make a contact print from it in the normal way, with the emulsion (picture) side of the paper negative toward the emulsion (shiny) side of the printing paper.

Disclaimer: The source of the images used I believe is Kodak but am not sure.

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Keywords: pinhole,camera,photography



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