The Sabattier effect

Initially, the term solarisation was used to describe the effect observed in cases of extreme overexposure of the negative in the camera. The effect generated in the dark room was then called pseudo-solarisation. This fine distinction is not made in the jargon of contemporary photography.

The effect was first described in print by H. de la Blanchere in 1859 in L’Art du Photographe. It was described again in 1860 by L.M. Rutherford and C.A. Seely, separately, in successive issues of The American Journal of Photography, and in the same year by Count Schouwaloff in the French publication Cosmos. The phenomenon should have been christened the Blanchere Effect, for it was not described by Sabatier until later in 1860 in Cosmos, and another paper published in 1862 in the Bulletin de Societe Francaise de Photographie.

The effect was usually caused by inadvertent severe over-exposure or occasionally by accidentally exposing an exposed plate or film to light before processing. Artist Man Ray perfected the technique which was accidentally discovered in his darkroom by his assistant Lee Miller. It is evident from publications in the 19th century that this phenomenon was invented very many times by many photographers as it tends to occur whenever a light is switched on inadvertently in the darkroom whilst a film or print is being developed.

In modern film photography, this effect can be emulated for artistic effect by briefly exposing the film to actinic light during chemical development. However, because of the speed of modern films, the effect is much more commonly seen in printing.

In solarisation, not only are parts of the image reversed in tone but a thin line is generated around areas of contrasting tone, called a Mackie line. If a film is treated the line is light, which produces a dark line in the print; when the print itself is processed it produces a white or light line around areas of high contrast. It is therefore always possible to determine whether a film or print has been used to produce the solarisation.