This was a positive image on a metal support.

The Daguerreotype was the first successful photographic process, the discovery being announced on 7 January 1839. The process consisted of

• exposing copper plates to iodine, the fumes forming light-sensitive silver iodide. The plate would have to be used within an hour.
• exposing to light - between 10 and 20 minutes, depending upon the light available.
• developing the plate over mercury heated to 75 degrees Centigrade. This caused the mercury to amalgamate with the silver.
• fixing the image in a warm solution of common salt (later sodium sulphite was used.)
• rinsing the plate in hot distilled water.

Daguerre's choice of chemicals was such that the action of light left a milky white image or mercury amalgam.

His first plates were 8 1/2" by 6 1/2"; it is interestting to note that this still remains the standard "whole-plate" today.

The quality of the photographs was stunning. However, the process had its weaknesses:

• the pictures could not be reproduced and were therefore unique;
• the surfaces were extremely delicate, which is why they are often found housed under glass in a case;
• the image was reversed laterally, the sitter seeing himself as he did when looking at a mirror. (Sometimes the camera lens was equipped with a mirror to correct this);
• the chemicals used (bromine and chlorine fumes and hot mercury) were highly toxic;
• the images were difficult to view from certain angles.

Many of the daguerreotypes that remain are noticeable for their detail, and this caused quite a sensation at the time. Indeed, the Spectator (2 February 1839) called daguerreotypes the "self operating process of Fine Art." The reaction in America was also one of amazement. The Journal "The Knickerbocker" for December that year quoted:

We have seen the views taken in Paris by the 'Daguerreotype,' and have no hesitation in avowing, that they are the most remarkable objects of curiosity and admiration, in the arts, that we ever beheld. Their exquisite perfection almost transcends the bounds of sober belief.

Carl Dauthendey, a photographer who became the first professional daguerreotype photographer in St. Petersburg, makes an interesting comment on the way Daguerreotypes were viewed:

"People were afraid at first to look for any length of time at the pictures he produced. They were embarrassed by the clarity of these figures and believed that the little, tiny faces of the people in the pictures could see out at them, so amazing did the unaccustomed detail and the unaccustomed truth to nature of the first daguerreotypes appear to everyone"

Sometimes the details might reveal something that the photographer had not intended. Fox Talbot, Daguerre's rival, observed:

"It frequently happens, moreover - and this is one of the charms of photography - that the operator himself discovers on examination, perhaps long afterwards, that he has depicted many things that he had no notion of at the time. Sometimes inscriptions and dates are found upon the buildings, or printed placards most irrelevant, are discovered upon their walls: sometimes a distant dial-plate is seen, and upon it - unconsciously recorded - the hour of the day at which the view was taken."

This capacity to record minute detail was put to good use by Jean Baptiste Louis Gros, an amateur who made the first images of the Parthenon whilst on a mission in Greece. On his return to Paris he discovered that on close inspection details which he had not observed could be examined, including the minutest sculptural elements.

In the museum at the Royal Photographic Society one of Daguerre's cameras is displayed. It was used by Talbot for his own process. However, there is an interesting omission: Daguerre's cameras always had a label on the side, bearing his signature, but Fox Talbot appears to have removed this!

One problem with early daguerreotypes was the length of exposure required - 10 to 15 minutes in bright sunlight. In fact, a daguerreotype in the International Museum in Rochester, depicting a chapel, states that the picture was taken between 4:40pm and 5:30pm on 19 April 1840. Such lengths were hardly suitable for portraiture. Fox Talbot noted in a letter dated 21 May 1852:

"Ld Brougham assured me once that he sat for his Dabguerreotype portrait half an hour in the sun and never suffered so much in his life."

To make photography possible, rests were used to keep the head still, and sitters had often to cope with brilliant sunlight. One photographer even used to run flour on the sitter's face, in order to reduce exposure time!

There was clearly a need to find some more effective ways of reducing the exposure time:

• On the chemistry side, J.G. Goddard started using bromide as well as iodine to sensitise plates, while Antoine Claudet experimented using chlorine.
  
  
• On the optical side, J. M. Petzval invented a portrait lens with an aperture of f3.6 (as opposed to f14, which was currently being used.) Petzval's lens was still being widely used almost a century later.

Taken together, these improvements enabled photographers to use exposures of between ten and thirty seconds, thus making portraiture more of a practical proposition. By March 1841 Beard had opened a studio at the Royal Polytechnic Institution, while Claudet opened one three months later, behind St. Martin's church, Trafalgar Square. In 1853 Daguerre's patent expired, and many daguerreotypists began to open for business. At that time, of course, all photographs were monochrome (it was not until after the time of Maxwell that colour photography became a possibility), so many artists turned to hand-colouring the photographs, which were almost invariably presented in ornate cases.

Colouring was a skilled and delicate affair. Typical of the kits was the Newman kit, dated 1850, with thirty-six colours. The colours would be applied very carefully with a fine brush, and then fixed simply by breathing on the plate itself.

The daguerreotype, aptly called a "mirror with a memory", was an amazing development, and one cannot but marvel at the intricacy of the detail. However, it was a blind alley as far as photography was concerned.


By Dr. Robert Leggat