Photographs

A brief history of the development of photography

In a relatively short period photography has grown from a process still in its experimental stages to one that is well established and widely used.

The evolution of photography is not simple and straightforward; it is the result of the efforts of many people working in a great range of disciplines. The following notes give a brief summary of the main contributors and the milestone discoveries.

Beginnings

Well before the beginning of the 19th century, much of the equipment and knowledge necessary for the eventual appearance of photography were available.

The camera obscura had been known since at least 1038, when it was described by Ibn Al-Haitham. It was not until the 17th and 18th centuries that its use became widespread.

The study of photochemistry was a by-product of research into other areas and it was known that:

• the action of light alone caused silver salts to darken (Schulze, 1727);

• further work, using silver chloride, established that violet light caused silver salts to darken far more rapidly than longer wavelengths of visible light (Scheele). Where it took fifteen seconds for silver chloride to darken when exposed to violet light, it took up to twenty minutes to darken to the same degree when exposed to red light (Senebier, 1782).

• silver chloride, which had darkened under the action of light, was insoluble in ammonia. The darkened substance was, in fact, metallic silver (Scheele); and

• some resins became insoluble in turpentine after exposure to light (Senebier).

At the beginning of the 19th century, a number of people began to see that it might be possible to obtain a permanent image using the camera obscura and light-sensitive materials.

Thomas Wedgewood and Sir Humphry Davy did some early work on this. They produced images by placing items on sensitised paper and leather and then exposing them to light, but were unable to fix the images.

The first photograph

In 1816 in France, Nicphore Nipce produced a negative image using paper sensitised with silver chloride and placed in a camera obscura. But he failed to fix the image.

He produced a permanent image in 1822, using bitumen of Judea, which hardened when exposed to light. An engraving, made transparent with oil, was placed over a glass plate coated in the bitumen. After several hours' exposure to light, the unexposed areas of bitumen could be dissolved in lavender oil—a light petroleum oil—leaving an image formed by the hardened bitumen of Judea.

In 1827 Nicphore Nipce became the first person to produce a direct positive photograph from nature. He called the image a heliograph. He had used a bitumen-coated pewter plate which he had placed in a small camera obscura and exposed for about eight hours.

The daguerreotype and the calotype

Photography was announced to the world in 1839. There were two processes employing slightly different manipulations of light-sensitive silver salts.

Daguerre announced his discovery in January 1839 and presented the details of the process to the world in August 1839.

Daguerreotype image. Photograph courtesy of Artlab Australia, reproduced with permission of Art Gallery of South Australia

A silver-plated copper sheet was exposed, first to iodine vapour to sensitise it, then to light, and finally to mercury vapour which developed the latent photographic image. The image was then fixed with sodium thiosulphate solution, washed and gently dried over a flame.

The image, a fine amalgam of silver and mercury, had to be protected from abrasion and oxidising agents, and was framed and enclosed in a case.

The daguerreotype was an immediate success, but it had two disadvantages:

• it was difficult to see: and,

• each daguerreotype was a one-off and could not be used to produce copies.

In 1839 William Henry Fox Talbot prepared his Account of the Art of Photogenic Drawing, or the process by which natural objects may be made to delineate themselves without the aid of the artist's pencil. This described how he sensitised paper by brushing it with silver nitrate and then sodium chloride. After exposing the paper to light for about two hours in the camera obscura, the image which formed in the paper was fixed using a concentrated sodium chloride solution. By late 1840, Fox Talbot had made significant improvements to his process.

He produced an iodised paper by coating writing paper with silver nitrate solution and then—before it dried—immersing it in potassium iodide solution, thus forming silver iodide in the paper. This paper could be stored for an indefinite period in the dark.

For use, the paper was washed with Fox Talbot's exciting liquid, then exposed for less than a minute, after which it was brushed again with the exciting liquid. The second application of exciting liquid developed the latent image. The photograph was then washed and fixed. This produced a negative image, which was then waxed to make it transparent.

By exposing sensitised paper in contact with the negative, positive images could be produced. This was the calotype process.

The calotype process formed the base from which modern photography evolved.

Its greatest advantage was that it was a two-stage process. Where previously a negative image had been a disappointment to the experimenter, it was now seen as the means with which to produce multiple positive copies.

Albumen paper and the wet collodion process

By the early 1850s most of the teething troubles of photography had been eliminated; and it was from this time that photography really flourished. In 1850 and 1851 two important improvements to photography were published: the albumen printing-out paper and the wet collodion process.

Albumen printing-out paper was introduced in 1850 and it became the most important print material of the 19th century.

Albumen print. Photograph courtesy of Fred Francisco

Albumen was prepared by beating egg-white until it was very frothy, and then leaving it to settle to a liquid. Most manufacturers allowed the albumen to ferment, because this improved the final print quality. Very thin rag paper was coated by floating it on top of an albumen and sodium chloride mixture. Before use, the paper had to be sensitised. This was done by floating the paper on a solution of silver nitrate.

For printing, the sensitised paper was placed in a frame in contact with the negative and exposed for periods ranging from a few minutes to a number of hours. Once the image had appeared, it was fixed.

Various improvements were made to albumen paper between 1850 and 1900. These include:

• the introduction of gold toning for use with albumen paper. This changed the image's colour from a red-brown to a warm purple-brown or blue-black, and improved the stability of the image;

• from the late 1880s platinum toning was also used, usually in combination with gold toning: it gave the image a nearly neutral tone. Platinum toning on its own turned the image brown;

• from 1863 dyes were added to the paper base to counteract the yellowing of the albumen layer. Pink was the most common dye; but green, blue and violet were also used; and

• ready sensitised albumen paper became available in the 1870s. The use of citric acid in the preparation of the paper gave it a shelf-life of several months.

The wet collodion process was announced by Frederick Scott Archer in 1851. This used glass as the carrier for the negative image.

Collodion, containing potassium iodide, was poured over the glass to form a thin, even film. This was immediately sensitised with a silver nitrate solution. The plate had to be exposed while still wet, and then developed with pyrogallic acid.

Sodium thiosulphate or potassium cyanide were used to fix the image, which was then washed and dried. Then the plates were often warmed to receive a protective varnish before any positive prints were made.

It was not an easy process. All the processes described above were done by hand. And if photographs were to be taken outside, a portable darkroom, complete with all chemicals, water and equipment, had to be carried.

Some of the chemicals were toxic, for example, potassium cyanide was used for fixing and for cleaning excess developer off the equipment.

The wet collodion process was extremely popular. The advantages of fine detail, improved tonal ranges and reduced exposure times, plus the fact that the process was not protected by patent, outweighed the disadvantages.

Collodion on glass negatives and albumen-coated paper positive prints were such a successful combination that they dominated photography for over 30 years.

Gelatine dry plates and film negatives

From the 1870s the use of dry gelatine plates became common; and then in the late 1880s film negatives were introduced.

The gelatine dry plate was put forward by Dr R.L. Maddox in 1871. Two years later, ready-coated plates were available.

Glass plates were machine-coated with gelatine containing light-sensitive silver bromide.

Glass plate negative. Photograph courtesy of Fred Francisco

The plates did not need any processing to sensitise them before use; they could be stored for many months and required much shorter exposure times than previous methods.

The first film negatives, introduced in the United States in 1888, were made from cellulose nitrate. This was extremely flammable and was gradually phased out in favour of safer film materials.

Collodion and gelatine emulsion papers

Not long after the introduction of collodion and gelatine as emulsions in negative processes, they were applied to paper for the production of positive photographic prints. In these processes the gelatine or collodion emulsions contained the light-sensitive silver salts when they were coated onto the paper. These photographic papers are called emulsion papers.

Collodion printing-out papers became available in 1867. The papers had a barium sulphate layer—the pigment baryta—between the paper and the emulsion, to overcome the problem of the collodion not sticking to the paper. The collodion contained silver chloride and citric acid.

Gelatine printing-out papers became available in the late 1880s.

The only difference between the two types of paper was in the nature of the binder, i.e. collodian or gelatine:

• they were both exposed to daylight in printing-out frames and processed in the same way;

• they both produced reddish-brown to purple-brown image colours; and

• photographs which were double-toned with gold and platinum tended to be neutral. Some papers were self-toning, that is, the necessary salts were contained in the emulsion and were released during fixing.

Most photographic papers after this time had a three-layer structure. The baryta layer produced a very smooth, opaque, white surface on which to coat the emulsion. The image quality was improved as the underlying paper fibres were masked and final image contrast was heightened. The emulsion layer was protected from chemically active substances which might have been present in the paper.

Developing-out papers

Chemical development of positive images was used as early as 1851 by Blanquart Evart in his commercial photographic printing firm. But development was not commonly used until the 1880s, when the materials of the gelatine dry plate method were applied to production of positive prints.

From about 1885, papers coated with gelatine containing silver bromide became available. At first the emulsion was coated directly onto the paper; after 1895 bromide developing-out papers were also coated with a layer of barium sulphate.

Silver bromide and gelatine emulsions were sensitive enough to allow enlargement of negatives.

Bromide developing-out papers produced neutral, black images with improved image stability. This was largely due to the structure and shape of the silver formed by the development process.

Developed images have much larger silver particles than printed-out images. Chemical development of positive prints produces filamentary silver, which is deposited as long, twisted strands. It is these larger, irregularly shaped silver particles that give neutral-toned images greater chemical stability

In printed-out papers the images are made up of small spherical particles of silver called photolytic silver. The particle size is directly proportional to the amount of light received during exposure. Photolytic silver produced warm-toned images, tending toward reds, browns and yellows. These small particles are very vulnerable to the chemical activity which results in image deterioration.

Chemical development of positive photographic images was the way forward for modern photography. In the first decade of the 20th century developing-out papers began to take over from printing-out papers.

Colour photography

From the early beginnings of photography, there was a desire to produce colour images. But it was some time before any practical systems of colour photography were available and it was many years before colour photography became the norm.

A number of different systems for producing colour images were tried. Many fell by the wayside, while others were altered in minor ways over many years to produce better colour and better quality images.

A full description of the developments is not necessary in such a brief history of photography, so only a few of the developments are listed below. These give some idea of when these developments took place in relation to the development of black and white photography.

In 1903 the Lumire brothers invented and patented the Autochrome process, the first practical system of colour photography. It was a coloured transparent image on glass.

A silver-gelatine emulsion was exposed through a screen of potato starch grains dyed orange, green and violet. After reversal processing, a positive silver image was produced which, when viewed through the colour screen, reproduced the original colours. Autochrome plates were produced in large quantities between 1907 and 1940.

The Tricolor Carbro—invented in 1905—was used commercially for the first time in 1919. Carbro prints were made by placing three carbon images, coloured with pigment, onto paper. The risk of fading was reduced by the use of pigments instead of dyes.

In 1935 Kodak Kodachrome was introduced. It was first a movie film, then introduced as a 35mm slide film the following year. Other film companies followed with their own colour films.

In 1939 the Diffusion Transfer process was invented. Initially it was intended as a method of rapid document copying. Now it is used in instant-picture cameras.

In 1941 Minicolor prints, made from Kodachrome slides, were made available for the first time.

Kodacolor, a method for producing colour prints from negatives was introduced in 1942.

In 1944, Kodak introduced the Dye Transfer technique. It largely supplanted Tricolor Carbro. It was used primarily by studio photographers or serious artists.

By this time the major hurdles in the development of colour photography had been overcome; from then on, many minor developments were made, resulting in the processes with which we are familiar today.