First, the name. We owe the name "Photography" to Sir John Herschel, who first used the
term in 1839, the year the photographic process became public. The word is derived from the
Greek words for light and writing.
Before mentioning the stages that led to the development of photography, there is one
amazing, quite uncanny prediction made by a man called de la Roche (1729-1774) in a work
called Giphantie. In this imaginary tale, it was possible to capture images from nature, on a
canvas which had been coated with a sticky substance.1 This surface, so the tale goes, would not
only provide a mirror image on the sticky canvas, but would remain on it. After it had been dried
in the dark the image would remain permanent. The author would not have known how
prophetic this tale would be, only a few decades after his death.
There are two distinct scientific processes that combine to make photography possible. It
is somewhat surprising that photography was not invented earlier than the 1830s, because these
processes had been known for quite some time. It was not until the two distinct scientific
processes had been put together that photography came into being.
The first of these processes was optical. The Camera Obscura (dark room) had been in
existence for at least four hundred years. There is a drawing, dated 1519, of a Camera Obscura
by Leonardo da Vinci; about this same period its use as an aid to drawing was being advocated.2
The second process was chemical. For hundreds of years before photography was
invented, people had been aware, for example, that some colours are bleached in the sun, but
they had made little distinction between heat, air and light.
In the sixteen hundreds Robert Boyle, a founder of the Royal Society, had reported that
silver chloride turned dark under exposure, but he appeared to believe that it was caused by
exposure to the air, rather than to light.
Angelo Sala, in the early seventeenth century, noticed that powdered nitrate of silver is
blackened by the sun.3 In 1727 Johann Heinrich Schulze discovered that certain liquids change
colour when exposed to light. At the beginning of the nineteenth century Thomas Wedgwood
was conducting experiments; he had successfully captured images, but his silhouettes could not
survive, as there was no known method of making the image permanent.The first successful
picture was produced by Niépce,using material that hardened on exposure to light.4
On 4 January 1829 Niépce agreed to go into partnership with Louis Daguerre. Niépce
died only four years later, but Daguerre continued to experiment. Soon he had discovered a way
of developing photographic plates, a process which greatly reduced the...