Talbot's discovery, almost by accident, of the calotype process in September 1840 transformed his art. Most importantly, the dramatic reduction in exposure times meant that he could now photograph living subjects, and as early as 10 October 1840 he made a successful and moving 30-second portrait of his wife Constance. Details of the process were revealed in the patent of 8 February 1841 (strictly speaking, the name referred only to the negative; prints continued to be made by the photogenic drawing method), to the Royal Society in June, and in scientific and popular journals. However, further refinements to the process in England would continue to revolve around Talbot and his circle.
Although Talbot hoped that calotype portrait studios would prove profitable his first licensee, the miniature painter Henry Collen, struggled to master the process. He required long exposure times, even after acquiring a special large-aperture lens from London's premier lens maker, Andrew Ross. Perhaps Collen was not a particularly competent technician, for Talbot himself produced some charming private portraits of his family, including several of his children. The masterly calotype portraits of Hill and Adamson were produced after much experimentation following lengthy correspondence between Talbot and his scientific friend in Scotland, Sir David Brewster.
Nicolaas Henneman and the chemist Thomas Malone, working on Talbot's behalf at the Reading printing establishment, acquired useful experience that led to some refinements to early practice. Talbot had often waxed negatives after processing, but although this offered greater negative transparency, it was found that it sometimes led to a not always desirable increase in contrast of the print and rather cold grey tones. The aim was to produce uniform prints of a rich mulberry colour. Nitric acid, ‘hypo’, and hot irons were all tried as toners, although there were worries about the long-term effects of these actions. Yet consistent quality remained a problem and was always dependent on impurity-free chemicals and the vagaries of the weather.
The calotype process was most popular with amateurs. Many did not bother to apply for a licence and the materials were cheap—good-quality writing paper and a limited range of common chemicals. Compared with the daguerreotype process, it was portable and convenient for travellers. It also enjoyed the advantage of being a negative-positive process, allowing numerous copies to be made. There were problems of course. The unpredictable nature of the early process required an experimental bucket-chemistry approach beyond the skills of many potential practitioners. It was not surprising, therefore, that several of the early English amateurs were relatives or friends of Talbot and constantly sought his advice. Talbot's associate, Calvert Jones, wrote regularly while calotyping in the Mediterranean, on one occasion complaining that even in the ‘energetic’ sunlight of Malta, he required a three-minute exposure.
The calotype process only became popular in France after 1847 when Blanquart-Évrard found that, by omitting gallic acid from Talbot's sensitizing solution and using it solely as a developing agent, he required shorter exposures and obtained clearer images. He was able to mass-produce prints in a standard range of hues and with a consistency of quality that had eluded Talbot. Gustave Le Gray's ‘dry’ waxed-negative technique of 1851 involved waxing negatives before they were sensitized and exposed, rather than after, as was Talbot's practice. This technique further shortened exposure times and allowed negative paper to be pre-prepared and kept for many weeks, a boon to travelling photographers. Calotype photography was never popular in America. Talbot sold calotype rights to the Langenheim brothers, operators of a successful daguerreotype studio in Philadelphia, but photographs on paper did not impress the American public and the venture was a financial disaster. During the 1850s the process was generally supplanted by
— John P. Ward
Bibliography
- Arnold, H. J. P., William Henry Fox Talbot (1977).
- Brettell, R., Flukinger, R., Keeler, N., and Kilgor, S., Paper and Light: The Calotype Process in France and Britain 1839-1870 (1984).
- Schaaf, L. J., The Photographic Art of William Henry Fox Talbot (2000)
