ON the chairman's last evening in office at the Prestwich Co-op Camera Club, he is given carte blanche to organise anything that takes his fancy.

Usually the evening is very interesting, as it was last Tuesday when Roy Taylor did some research on the origins and developments of photography in the 19th century.

The basic elements have been known for about 400 years and some of the earlier artists projected an image on to a sheet of glass using a lens or a pinhole to lay out the basis of a print with the correct perspective.

In the early 1700s, it was discovered that silver salts would turn black when exposed to light.

In 1832 Niepce projected an image on to white bitumen and produced an image after about eight hours' exposure to give us the first photograph.

He collaborated with Daguerre and in 1839 they coated a clean copper plate with silver. They sensitised this in mercury vapour to give a copper iodide coating. An image was projected onto it and it was intensified with mercury vapour. It was fixed in hypo and this was the Daguerreotype. They were all the rage on the continent for many years but, unfortunately, each was a one-off and could not be copied.

In England, Fox Talbot patented the Calotype process. Good quality paper was dipped in silver chloride (later silver bromide) on which a negative image was produced in his mousetrap cameras. This could be placed on a similar piece of paper and, with the sunlight shining through them, a positive contact print was made. Many positive prints could be made from the same negative and this is the process used today.

Many developments were made. In 1851 the wet process used collodion solution on glass but it had to be exposed before it dried. In 1871 gelatin containing silver bromide could be coated on to glass and dried to start the dry plate process.

It was found that paper could be used instead of glass, hence bromide paper. Later, modified celluloid was used to produce roll film.

So developments went on. The first Kodak camera in 1888 had a roll of film for 100 pictures. This had to be returned for developing and printing and it was returned with the prints and reloaded. The Box Brownie, with celluloid roll film, was introduced in 1900. Progress in film, cameras, lenses and all the other things connected with photography has continued to this day.

Roy and his associates - Phil Cohen who produced the images and Vernon Barlow with Allan Hardman who projected them - were properly thanked for an interesting evening.

We were reminded that next Tuesday will be the annual general meeting and if you don't attend you will not have a say in any proposals!

G. E. WILSON