Pinhole photography is an age-old science that has been exploited and enjoyed for well over a century by children as well as renowned artists and photographers, space scientists and firms selling surveillance systems that use a pinhole instead of a lens in tiny cameras.

Like pot-holing in caves, pin-holing is a hobby that drags you in deeper and deeper once you dive in. Both children and adults enjoy the magic of making a photograph appear out of almost nothing, while artists continue to be attracted and enticed by the ephemeral quality of the images produced. Scientists, meanwhile, have exploited it to reveal the wonders of the universe.

With help, primary pupils can easily undertake this as a project, incorporating skills in planning and estimating, calculating and construction, while learning a bit about art history and the science of the image-forming properties of light.

A pinhole camera differs from its conven-tional counterpart by lacking a lens to focus the image, and is incredibly cheap to make and easy to use. Almost any light-proof container can be made into a pinhole camera, from a full-size room to a small match box.

Depending on their size, pinhole cameras can take pictures on light sensitive photographic enlarging paper or film. So what is the easiest, quickest and cheapest way to get started?

Making a pinhole camera

To make a camera you need: an old biscuit tin, some black matt paint, a drill, a piece of metal from a drinks can and some black electrical tape (picture number 1, below).

Drill a hole in the side of the biscuit tin about 5mm diameter (picture 2); measure a 20mm square piece of metal on the drinks can and mark it with a pencil (3). Carefully cut out the piece with a craft knife (4) and using a sewing needle (try size 9) punch a 0.5mm diameter hole in the centre of it (5).

Black tape this pinhole plate on the inside of the biscuit tin, centering the tiny hole in the middle of the main hole in the tin (6).

Cut a 40mm length of black tape (7) and place it over the pinhole on the outside of the biscuit tin, completely covering it (8).

Paint the inside of the tin with matt black paint and leave to dry (9). Within half an hour you can make a usable pinhole camera for less than pound;5.

Being usable is an important criteria - in many schools pinhole cameras are regularly made in science classes. The normal method is to take a shoe box, cut it away at one end and put some tracing paper over it. Make a hole at the other end with a pencil and cover with a piece of tin foil with a small hole in it. Throw a coat over your head and point your shoe box towards a window and voila!, you can see an image of real life going on upside down and back to front.

Why not then go a one step further and make a photograph? This demonstrates why people made and used pinhole cameras - they wanted a record of what they had seen to show and astonish their friends. Children and adults alike are still astonished by the wonder of animage coming out of a biscuit tin.

To complete your experiment you need a darkroom. One could be set up using a whole classroom or a broom cupboard. Ensure that all light is excluded and then place a red safelight above a flat work surface. Photographic safe lights can be bought from most high street photographic shops, but you can make do with a ceiling-mounted red light bulb.

You will also need a pack of multigrade black and white photographic paper, and three black and white photographic chemicals: developer, stop bath and fixer. Rubber gloves help you move the paper between the trays without getting any chemicals on your fingers.

The paper and chemicals should cost less than pound;20 and will allow you to work on the project with a full class group or individually to enjoy many fun sessions developing skills.

The easiest way to ensure you do the right thing is to explain what you are trying to do. You will need to mix the chemicals as per instructions and put them in three shallow trays about 5cm deep and 20 x 30 cm, and you will need a bucket of plain water to wash your prints in.

Most children from six or seven are quite able to understand the necessary health and safety points and teachers can use their discretion to allocate tasks, demonstrate some aspects and allow hands-on for other parts of the activity as appropriate. Missing out on seeing their picture appearing out of the chemicals under that special red lighting would deprive pupils of the magic of photography.

Taking a photograph

Once your camera is ready to make a photograph, take it into the darkroom. Under red light, open your pack of photographic paper and cut a sheet to fit the side of your biscuit tin that is opposite the pinhole. Using some Blu-tac stick it in with the shiny surface facing the pinhole (10).

Shut your biscuit tin making sure it is firmly closed and take it outside into a sunny or open light area. Put your camera on a flat surface and point the pinhole towards something you would like to photograph. Holding your camera firmly down to avoid any movement, peel back the black tape over the hole and let light in to our pinhole camera. As a general rule, allow the following exposure times: Bright sun: 64 seconds Hazy sun: 128 seconds Light cloud: 256 seconds Overcast: 512 seconds (Based on a tin 130mm wide )

Stick the black tape back over the hole - be careful not to move the camera while the pinhole is uncovered.

Developing your picture

Now take your pinhole camera back into the darkroom. Under red safe light open your camera, take out the photographic paper that will still be white at this stage, and put it into the diluted developer for one and a half minutes - a black and white negative image should gradually appear. To complete the process you need to put the paper into the stop bath, then the fixer and finally in to the water for a wash. You can now look at it under normal light, where you can assess your picture.

How did it turn out?

If the photographic paper looks very black, too much light went through the pinhole, so make the hole smaller or expose for fewer seconds. If the paper is white or has a dim image on it, make the hole bigger andor give more seconds. Eventually, by trial and error and recording your results, you will produce a black and white negative image.

If everything is black it is likely your camera has a light leak, while if your paper stays permanently white the paper is probably round the wrong way. If the image looks fuzzy your camera may have moved during the exposure time or your pinhole might be a bit rough.

Making a final positive print

Once you have a satisfactory first negative, you can make a contact print to make a positive image. Under a red safe light, place a fresh sheet of photographic paper shiny side up on the work surface. Put your negative print image side down on top of it. Place a piece of perspex over the two to keep them flat and expose your new sheet of paper to a white light source for about five seconds. Process as before and assess the results as you did for your pinhole negative.

For more information, Pinhole Photography - a beginner’s guide - is a good starting point. The booklet is pound;4.95 from Picture House Centre for Photography, International House, 125 Granby Street, Leicester LE1 6FD. Tel: 0116 2555282 Email: photo@pichouse.demon.co.ukFor more detailed information see thepinhole resources website: www.pinholeresource.com Anna Smalley is co-director of the Picture House Centre for Photography in Leicester

A BRIEF HISTORY

Pinhole images and their formation have vexed and intrigued people for hundreds of years. Photography as we know it came about as the result of two separate developments: one in optical science, with the camera obscura, and the other, in chemical science, with the discovery that silver salts were photosensitive, or sensitive to light.

The image-making qualities of a very small hole was noted in Greek and Roman times, and possibly even earlier in China. Around 330bc, Artistotle recorded the creation of images in a darkened room, when light passed through a small hole and fell on a surface opposite the hole.

Awareness of this phenomenon was used by painters and architects in the creation of camera obscuras, a phrase first used by Johannes Kepler (1571-1630), “camera” meaning room and “obscura” meaning dark. Painters could sit inside room-sized camera obscuras and record the image projected on to the wall opposite. Simple lenses and mirrors were later incorporated into the camera obscuras giving sharper and larger images, and the possibility of focusing. Camera obscuras flourished at seaside and other scenic locations.

For many years the scene was set for photography - literally “drawing with light” - to be created. All that remained was to find a way to preserve the images projected in the camera obscuras. In 1839 the Frenchman Louis Daguerre and the Englishman William Henry Fox Talbot were jointly credited with inventing the first permanent photographic image. Talbot discovered that ordinary paper could be coated with a weak salt solution, followed by a stronger silver nitrate solution.

This was repeated several times before the paper was ready and placed in a simple wooden camera. Light passed through the lens on to the paper recording whatever the camera was pointed at. At first the image would disappear when viewed in ordinary daylight, but then it was found that salt helped make the picture last longer. Eventually the astronomer Sir John Herscel discovered that sodium thiosulfate could preserve the image almost indefinitely.

FACT FILE

* In the 16th century pinhole photography was used to study solar eclipses

* A drawing from 1689 by Cornelius Meyer shows how pinhole spectacles can help near-sighted people

* Innuit have long used pinhole glasses to avoid snow blindness

* The mollusc Nautilus has a natural pinhole eye

* The first commercial pinhole camera was made in France in 1887

* In 1892, 4,000 pinhole cameras called “Photominibuses” were sold in London

* In the 1940s it was found that pinhole cameras could be used to photograph high-energy X-rays and gamma rays from the sun. The pinhole has been widely used by nuclear physicists to photograph high energy in laser plasma