Henry Fox Talbot’s original calotype process of 1841 consisted of treating good quality writing paper with light-sensitive chemicals and placing the prepared sheet in a camera. After exposure, the paper with the as yet invisible, or latent, image was removed from the camera and developed chemically to produce a negative. Placing a second piece of sensitized paper in direct contact with the negative and exposing both to the sun created a positive of the image in the form of a salted paper print.
French photographers modified Talbot’s calotype process, patented in England and France, in the late 1840’s and early 1850’s to make the process simpler and more reliable. Gustave Le Gray further adapted the process by applying bee’s wax to the paper negative before sensitization. This not only strengthened the paper but also, by its transparency, allowed more light to pass through, thereby creating a sharper image. In addition, these negatives could be prepared in advance, exposed, and kept for several days before being developed. Maxime Du Camp, John Beasley Greene, August Salzmann, and Félix Teynard, whose work is shown on the facing wall, all used paper negatives during their travels.
Charles Nègre’s view of the church of Saint-Gilles du Gard shows the relationship between the waxed paper negative and salted paper print positive. Due to chemical limitations, it was difficult to achieve a proper exposure for both sky and foreground. To circumvent this, ink was often used to black out the sky on the negative before printing, thereby rendering it white in the resulting positive image. Paper negatives now have tremendous aesthetic appeal, due to the luminous beauty of their reversed tones, as Gustave de Beaucorp’s negative reveals.