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Shedding Light on the Autochrome

The Lumière family was not only innovative in cinema, but also in photography, where its inventions made a considerable mark. At the start of the 20th century, the Lumière brothers marketed the Autochrome plate, the first industrial color photography process based, surprisingly, on potato starch. Two French researchers recently revisited the Autochrome, conceived not without difficulty and protected by secrecy for many years.

Soon the whole world will run wild with color, and the Lumière brothers will be responsible,” intuitively proclaimed the American photographer Alfred Stieglitz when the Autochrome plate was first put on sale in 1907. And this industrial color photography process enjoyed considerable success, as the Lumière brothers went on to sell millions of Autochrome plates over the following decades. To better understand the technology behind the Autochrome, researchers Bertrand Lavédrine, director of the CRCC,1 and Jean-Paul Gandolfo, professor at the film school ENS Louis-Lumière, decided to revive it, more than half a century after it went out of production.

1

© Y. Cornu (avec l'aimable autorisation des descendants d'Édouard Blanc)

Autochrome self-portrait of Édouard Blanc, a chemist at the Lumière factory in Monplaisir (Lyon), around 1907.



Painstakingly recreating the steps involved in making Autochromes, they began by selecting minuscule grains of potato starch, dyeing them violet, green, or orange, and mixing them. They then sprinkled millions of these grains onto a varnished glass plate and added lampblack—soot from oil lamps—to fill the gaps between the grains. This was followed by lamination—pressing the plate—and a second application of varnish. The final step—the most difficult to recreate by hand on small plates in a dark room—was the application of the final layer of the Autochrome, a black and white emulsion of gelatino silver bromide, a light-sensitive substance which requires particular care.

10

© J.-P. Gondolfo

A press used for flattening the starch grains has been restored and is now classified as a historic monument.



The device works on the basis of “additive color synthesis,” the principle that enables all color hues to be created from only three primary colors (red, green, and blue) and which was later to be used in television screens. In Autochromes, the photosensitive layer is exposed to light rays, which are filtered beforehand by the dyed grains of starch. After taking the picture and developing it, the silver grains in the photosensitive layer mask certain colored grains of starch to a greater or lesser extent, thus recreating the colors of the original image photographed. The image appears by viewing the transparent positive print in a special device or by projecting it as a slide. “The grains are extremely small, invisible to the naked eye. An optical mixture of the different starch colors is then created within the eye... resulting in the palette of colors visible in the Autochrome,” explains Lavédrine.
If the underlying principle of the Autochrome (first formulated by French inventor Louis Ducos du Hauron) is sound, it nevertheless took seven years for the mighty Lumière family business, already specialized in photography and cinema, to launch its industrial production. The choice of starch for example, a key aspect of the invention, required months of head scratching. Potato grains were preferred to rice grains, which take on colors less easily.

13

© Musée Albert-Kahn / Dép. des Hauts-de-Seine

Paris, 1918. The author, Auguste Léon, worked for the “Archives de la Planète,” an immense photo- and cinematographic record of the epoch, founded by the banker Albert Kahn. Today, the Albert-Kahn Museum archives some 72,000 Autochromes.



For this in-depth study of Autochromes, Lavédrine and Gandolfo also struggled for many years. Not only did they try to produce them but, as they explain in their book L'Autochrome Lumière,2 they also interviewed the children of eyewitnesses from the period, dissected laboratory notebooks, and analyzed the dyes in old plates. They also closely examined a lamination press, which the Lumière brothers chose not to patent, probably to keep it unique. Lamination—a crucial phase which, by squashing the grains against each other, enhanced the transparency of the granular network—was indeed alluded to in a patent, but only in an elusive manner. Competitors were thus kept at bay. And they needed to be: at the turn of the 20th century, photography, which was invented in 1839, was thriving. Creating photographs in color was a major challenge, and the object of much research and experimentation which benefited from the scientific progress on light phenomena and color recombination.
With the Autochrome, photography finally adopted color. But the process proved fragile and the production of Autochrome plates difficult. The exposure time, approximately one second, virtually precluded instantaneity. Despite both this weakness and their high price, millions of Autochrome plates were sold throughout the world in 30 years. In 1931, the glass plates were replaced by a flexible substrate, but it was only in the mid-1950s, two decades after the introduction of the more popular Kodachrome, that the invention fell into obsolescence, and that the Lumière factory ceased production of its Alticolor films, direct descendants of the Autochrome plate. Beside its obvious historical interest, a more in-depth understanding of this technology should no doubt help us better preserve the existing samples.

Mathieu Hautemulle

Notes :

1. Centre de recherche sur la conservation des collections (CNRS / Ministère de la culture et de la communication / Muséum national d'histoire naturelle).
2. Bertrand Lavédrine and Jean-Paul Gandolfo, L'Autochrome Lumière (Paris: Editions du CTHS, 2009).

Contacts :

Bertrand Lavédrine,
CRCC, Paris.
lavedrin@mnhn.fr


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