Photographic Techniques, History of

I

Introduction

Photographic Techniques, History of, development of photographic processes, starting with the recognition that certain chemicals changed tone as a result of exposure to light. Not until the 1820s, however, was the objective achieved of permanently fixing an image made by exposure to light. Since that time, scientists have continued to refine and improve the chemical and optical aspects of the photographic medium.

II

Pioneer Processes

The earliest surviving photograph is a direct positive image on a pewter plate, fixed in Bitumen of Judea (a type of naturally occurring solid bitumen mined in the Middle East). It dates from 1826 or 1827 and is a view of a courtyard from his window by the Frenchman Joseph Nicéphore Niépce. The plate required an eight-hour exposure. The resulting image represented a momentous stage in the pursuit of a goal which had intrigued scientists through the long pre-history of photography. Notable attempts to capture the images made by light on light-sensitive chemicals had been pursued by the British scientists Thomas Wedgwood and Sir Humphry Davy at the end of the 18th century. They were unsuccessful in fixing the images they had made, however. Niépce's image, though fixed, was crude and fell short of the necessary quality and convenience of use which would have ensured the adoption of his technique.

It fell to another man, Louis Jacques Mandé Daguerre, who became Niépce's associate and worked on independently after his death, to bring these first tentative achievements to a level of refinement which would guarantee their success with the public. Daguerre followed the path of making single direct positive images on metal plates. He experimented through the 1830s and in 1839 made the historic announcement of his daguerreotype process. This involved exposing a silvered copper plate, bearing a light-sensitive layer of silver iodide, developing the image in mercury vapour, and fixing it in a strong salt solution. The resulting images were fragile to the touch and needed to be protected under glass, but were capable of recording the finest detail.

Simultaneously through the late 1830s, the British scientist William Henry Fox Talbot had been pursuing his own experiments. His earliest successes were achieved in 1835 and included contact printings of plant stems and leaves and views made in his miniature cameras (the so-called “mouse-trap” cameras). These were negative images on paper prepared with solutions of light-sensitive silver salts, fixed at first in common salt and, later, at the suggestion of Sir John Herschel (the distinguished British astronomer), in sodium thiosulphate, commonly known as “hypo”. Talbot called his process photogenic drawing, and on January 31, 1839, spurred on by news of Daguerre's progress, he read a paper to the Royal Society, entitled “Some Account of the Art of Photogenic Drawing”. The next and crucial stage in Talbot's investigations was the discovery of the “latent” image, the invisible product of a short exposure, which could be chemically “developed”. His refinements, which were summarized in the patents of his improved “calotype” process (registered on February 8, 1841), laid the basis for the progress of photography: the creation in the camera of a negative from which, once developed and fixed, any number of positive prints could be made.

Notable independent experiments were made by other scientists. The Frenchman Hippolyte Bayard discovered his own methods for making direct positives on paper in 1839. Sir John Herschel devised his own photographic formula in the same year, making a historic negative on glass of his telescope. He made valuable contributions to the progress of the medium, not least through his recommendation of “hypo” as a fixing agent, his constructive relationship with Talbot, and his discovery of the “cyanotype” process, used by Anna Atkins in her publication Photographs of British Algae, the first part of which was published in October 1843, pre-dating the appearance of Part I of Talbot's The Pencil of Nature (1844), and thus becoming the earliest publication to be illustrated with actual photographs.

III

The Glass Negative and Refined Paper Processes

The discoveries of both Daguerre and Talbot were protected by patents; both processes had inherent qualities and disadvantages. Daguerre's plates were capable of remarkable clarity but could not be easily reproduced, while Talbot's paper negatives precluded fine detail. The announcement in 1851 by Frederick Scott Archer of his collodion on glass negative process at once resolved these questions, making possible negatives as sharply detailed as a daguerreotype and capable of producing any number of prints. The collodion on glass process was not the first glass negative process. In 1847 Claude Felix Abel Niépce de Saint-Victor had proposed glass negatives with albumen as the suspension agent for the sensitive chemicals. The process gave a high-quality negative but required a long exposure. Scott Archer's process had the disadvantage of demanding the use of wet chemicals, so negatives had to be prepared and developed as and when they were used, making fieldwork cumbersome. Exposure times, however, were reduced to a practicable level by further developments and the collodion on glass process was to dominate the following three decades.

Paper negatives remained in use until the late 1850s and numerous practitioners sought ways of improving their quality, since, for work in difficult terrain, they still had the advantage that they could be prepared and developed at leisure. The French photographer Gustave Le Gray devised the process of waxing the negative paper before sensitization, thus achieving a clarity close to that of glass. His processes, which included alternative chemical formulae to those of Talbot, were published in 1852 and helped to extend the use of paper for negatives.

Another Frenchman, Louis-Désiré Blanquart Evrard deserves mention for his innovations in paper photography and publishing. He published and patented his variant of Talbot's process, which involved impregnating rather than coating the negative paper and thereby achieving greater tonal range and detail. In July 1851 he opened an establishment at Lille which provided the facilities to print the work of a circle of photographers including Maxime du Camp, Henri Le Secq, and Charles Marville. Blanquart Evrard went on to publish a great deal of this work in a fine series of projects, issuing high-quality volumes devoted to individual photographers and specific topics or gathering multi-author anthologies of artistic images.

IV

Industrialization and Popularization

By the late 1850s the massive commercial exploitation of photography was well under way. Among the first popular applications of Scott Archer's glass negative was the ambrotype, an underexposed collodion negative which, when backed with black, appeared as positive. Mounted in small fancy cases, these provided a cheaper alternative to the daguerreotype and enjoyed a lasting popularity for portrait studio work. In 1854 André Adolphe Disdéri applied for a patent for an idea which was to enjoy a phenomenal success through several decades. This was the carte-de-visite, a small format (about 85 by 55 mm/3.3 by 2 in) portrait on paper, mounted on card and intended as a visiting card. They were produced in their millions, both for exchange between friends and family and, with portraits of every category of celebrity, as images to collect and treasure in albums. The 1860s witnessed the heyday of the carte-de-visite and no photographer brought greater skill to this format than the Frenchman Camille Silvy in his London studio.

An image-hungry public provided a ready market for topographical as well as portrait subjects and showed particular favour through the late 1850s and 1860s to stereoscopic photographs. Proposed by Scottish scientist Sir David Brewster, stereoscopic photography involved making pairs of negatives and prints to replicate the process of human vision. When viewed through the stereoscope the impression of depth would be recreated. Used at first with the daguerreotype process, stereoscopic photography became widely popular in the form of paper prints, mounted side by side on card and embracing every conceivable range of subject matter.

Photography in its popular forms provided the most effective means of spreading visual information about the appearance of the world and the people who were shaping its history. Photographs, typically those distributed in stereoscopic format, also provided entertainment and amusement and could serve a didactic moral purpose.