Autochrome Lumière

Autochrome is an additive color[6] "mosaic screen plate" process. The medium consists of a glass plate coated on one side with a random mosaic of microscopic grains of potato starch[7] dyed red-orange, green, and blue-violet (an unusual but functional variant of the standard red, green, and blue additive colors); the grains of starch act as color filters. Lampblack fills the spaces between grains, and a black-and-white panchromatic silver halide emulsion is coated on top of the filter layer.

Unlike ordinary black-and-white plates, the Autochrome was loaded into the camera with the bare glass side facing the lens so that the light passed through the mosaic filter layer before reaching the emulsion. The use of an additional special orange-yellow filter in the camera was required to block ultraviolet light and restrain the effects of violet and blue light, parts of the spectrum to which the emulsion was overly sensitive. Because of the light loss due to all the filtering, Autochrome plates required much longer exposures than black-and-white plates and films, which meant that a tripod or other stand had to be used and that it was not practical to photograph moving subjects.[8] The plate was reversal-processed into a positive transparency — that is, the plate was first developed into a negative image but not "fixed", then the silver forming the negative image was chemically removed, then the remaining silver halide was exposed to light and developed, producing a positive image.

The luminance filter (silver halide layer) and the mosaic chrominance filter (the colored potato starch grain layer) remained precisely aligned and were distributed together, so that light was filtered in situ. Each starch grain remained in alignment with the corresponding microscopic area of silver halide emulsion coated over it. When the finished image was viewed by transmitted light, each bit of the silver image acted as a micro-filter, allowing more or less light to pass through the corresponding colored starch grain, recreating the original proportions of the three colors. At normal viewing distances, the light coming through the individual grains blended together in the eye, reconstructing the color of the light photographed through the filter grains.

To create the Autochrome color filter mosaic, a thin glass plate was first coated with a transparent adhesive layer. The dyed starch grains were graded to between 5 and 10 micrometers in size and the three colors were thoroughly intermingled in proportions which made the mixture appear gray to the unaided eye. They were then spread onto the adhesive, creating a layer with approximately 4,000,000 grains per square inch but only one grain thick. The exact means by which significant gaps and overlapping grains were avoided still remains unclear. It was found that the application of extreme pressure would produce a mosaic that more efficiently transmitted light to the emulsion, because the grains would be flattened slightly, making them more transparent, and pressed into more intimate contact with each other, reducing wasted space between them. As it was impractical to apply such pressure to the entire plate all at once, a steamroller approach was used which flattened only one very small area at a time. Lampblack was used to block up the slight spaces that remained. The plate was then coated with shellac to protect the moisture-vulnerable grains and dyes from the water-based gelatin emulsion, which was coated onto the plate after the shellac had dried. The resulting finished plate was cut up into smaller plates of the desired size, which were packaged in boxes of four. Each plate was accompanied by a thin piece of cardboard colored black on the side facing the emulsion. This was to be retained when loading and exposing the plate and served both to protect the delicate emulsion and to inhibit halation.

The 1906 U.S. patent describes the process more generally: the grains can be orange, violet, and green, or red, yellow, and blue (or "any number of colors"), optionally with black powder filling the gaps. Experimentations within the early twentieth century provided solutions to many issues, including the addition of screen plates, a yellow filter designed to balance the blue, and adjustments to the size of the silver halide crystals to allow for a broader spectrum of colour and control over the frequency of light.[9]

Because the presence of the mosaic color screen made the finished Autochrome image very dark overall, bright light and special viewing arrangements were needed for satisfactory results.

Stereoscopic Autochromes were especially popular, the combined color and depth proving to be a bewitching experience to early 20th Century eyes. Usually of a small size, they were most commonly viewed in a small hand-held box-type stereoscope. Larger, non-stereoscopic plates were most commonly displayed in a diascope, which was a folding case with the Autochrome image and a ground glass diffuser fitted into an opening on one side, and a mirror framed into the other side. The user would place the diascope near a window or other light source so that light passed through the diffuser and the Autochrome, and the resulting back-lit, dark-surrounded image would be viewed in the mirror. Slide projectors, then known as magic lanterns and stereopticons, were a less common but especially effective display technique, more suitable for public exhibitions. Unfortunately, projection required an extremely bright and therefore hot light source (a carbon arc or a 500 watt bulb were typical) and could visibly "fry" the plate if continued for more than two or three minutes, causing serious damage to the color.[10] More than a few surviving Autochromes suffer from such "tanning" and conventional projection is not a recommended means of displaying these irreplaceable images today.

However, a projector-like optical system (i.e., using condenser lenses for illumination, with a viewing lens in place of the projection lens), employing daylight (not direct sunlight) for the light source, can produce comparably excellent visual results—although for only one viewer at a time—without the unacceptable hazards of actual projection.

The use of a "light box" or similar highly diffused artificial light source for viewing Autochromes, although now nearly universal, is unfortunate, as the heavy scattering of light within and among the several layers of coatings on the plate degrades the color saturation. The slight pinkish tinge caused by colloidal scattering (the effect seen through a glass of water into which a couple of drops of milk have been mixed) is exacerbated, and the use of artificial light—especially fluorescent light—upsets the color rendition of a system which the Lumière Brothers carefully balanced for use with natural daylight.

Making modern film or digital copies of Autochromes introduces other problems, because a color system based on red, green, and blue is used to copy an image that exists within the red-orange, green, and blue-violet system, providing further opportunities for color degradation. Vintage reproductions of Autochromes in old books and magazines have often been noticeably hand-adjusted by the photoengravers in an effort to compensate for some of the difficulties of reproduction, and as a result they sometimes look more like hand-colored photographs than "natural color" ones. In short, it is very difficult to form an accurate impression of the appearance of any Autochrome image without seeing the original "in person" and correctly illuminated.

The lamination of the grains, varnish and emulsion makes autochrome plates susceptible to deterioration with each layer being vulnerable to changes in environment including moisture, oxidation, cracking, or flaking as well as physical damage from handling; Solutions include conservative lighting conditions, chemical free materials, medium-range humidity control of between 63 and 68 degrees Fahrenheit, and a well designed preservation plan.[11]

If an Autochrome was well made and has been well preserved, color values can be very good. The dyed starch grains are somewhat coarse, giving a hazy, pointillist effect, with faint stray colors often visible, especially in open light areas such as skies. The smaller the image, the more noticeable these effects are. Autochrome has been touted as “the colour of dreams.”[12] The resulting "dream-like" impressionist quality may have been one reason behind the enduring popularity of the medium even after more starkly realistic color processes had become available.

Although difficult to manufacture and relatively expensive, Autochromes were relatively easy to use and were immensely popular among enthusiastic amateur photographers, at least among those who could bear the cost and were willing to sacrifice the convenience of black and white hand-held "snapshooting." Autochromes failed to sustain the initial interest of more serious "artistic" practitioners, largely due to their inflexibility. Not only did the need for diascopes and projectors make them extremely difficult to publicly exhibit, they allowed little in the way of the manipulation much loved by aficionados of the then-popular Pictorialist approach.[13]

Autochromes continued to be produced as glass plates into the 1930s, when film-based versions were introduced, first Lumière Filmcolor sheet film in 1931, then Lumicolor roll film in 1933. Although these soon completely replaced glass plate Autochromes, their triumph was short-lived, as Kodak and Agfa soon began to produce multi-layer subtractive color films (Kodachrome and Agfacolor Neu respectively). Nevertheless, the Lumière products had a devoted following, above all in France, and their use persisted long after modern color films had become available. The final version, Alticolor, was introduced in 1952 and discontinued in 1955, marking the end of the nearly fifty-year-long public life of the Autochrome.[14]

Between 1909 and 1931, a collection of 72,000 autochrome photographs, documenting life at the time in 50 countries around the world, was created by French banker Albert Kahn. The collection, one of the biggest of its kind in the world, is housed in The Albert Kahn Museum (Musée Albert-Kahn) on the outskirts of Paris.[15] A new compilation of images from the Albert Kahn collection was published in 2008.[16] The National Geographic Society made extensive use of autochromes and other mosaic color screen plates for over twenty years. 15,000 original Autochrome plates are still preserved in the Society's archives. The collection contains unique photographs, including numerous Autochromes from Paris by Auguste Léon from 1925 and by W. Robert Moore from 1936 just before WWII.

In the U.S. Library of Congress's huge collection of American Pictorialist photographer Arnold Genthe's work, 384 of his autochrome plates were among the holdings as of 1955.[17]

The George Eastman Museum in Rochester, N.Y. has an extensive collection of early colour photography, including Louise Ducos Du Hauron's earliest autochrome images and materials used by the Lumiere brothers.

Bassetlaw Museum in Retford, Nottinghamshire holds a collection of over 700 autochromes by Stephen Pegler. This includes a collection of over 100 plates purchased by the museum in 2017 thanks to the generosity of local individuals and organisations.[18]The images cover a range of subjects from still lifes, posed studies, local people and landscapes, and his travels abroad, and were taken between 1910 and the early 1930s. The Pegler collection of autochromes is thought to be the largest collection of autochromes by one photographer in Britain today.[19]

The Royal Horticultural Society, UK has among the earliest colour photographs of plants and gardens taken by amateur photographer William Van Sommer (1859 - 1941), including of RHS Garden Wisley taken around 1913.[20]

One of the first books published with color photography used this technique. The 12 volumes of "Luther Burbank: His Methods and Discoveries, Their Practical Application" included 1,260 color photographs and a chapter on how this process worked.

In the early 1900s Ethel Standiford-Mehlingan was an experimental photographer and artist and owner of the Standiford Studio in Louisville, Kentucky. She was commissioned by Louisville artist and art patron Eleanor Belknap Humphrey to create an autochrome diascope of her two oldest children. Both the autochrome photograph of the Humphrey children and the diascope mirror viewing device, which closes into itself in a leather-bound case similar in size and appearance to a book, are well preserved and still viewable in 2015. Ethel Standiford-Mehlingan later moved her Louisville enterprise Standiford Studios to Cleveland, Ohio[21] and it is not known if any other examples of her autochrome diascopes still exist.

Vladimír Jindřich Bufka was a pioneer and popularizer of Autochrome in Bohemia.

There has been a revival of interest in the process by some, including a few groups in France working with original Lumiere machinery and notes. One such recreation is a series of images from 2008 by the French photographer Frédéric Mocellin.[22]

• The 2006 film The Illusionist tried to recreate the look of Autochrome, although apparently basing that "look" on published reproductions rather than on actual Autochrome plates.[23]
• Modern image sensors in digital cameras most commonly use a Bayer filter, which works in essentially the same way as the colored starch grains in an Autochrome plate—by breaking up the image into microscopically small color-filtered elements. In physical arrangement, however, the Bayer filter mosaic much more closely resembles the regular geometric pattern used in other color screen plates of the Autochrome era, such as the Paget and Finlay plates.

• Autochrome images
• 
  An Autochrome of the Taj Mahal reproduced in The National Geographic Magazine, March 1921.
• 
  An Autochrome of the pavilion of Poland in Paris 1925.
• 
  An Autochrome of a World War I Nieuport 23 biplane fighter, circa 1917.
• 
  Mirror view in a diascope of a 1913 Autochrome of Percy MacKaye, photographed by Arnold Genthe.
• 
  House in Stockholm, Autochrome, 1930.
• 
  Autochrome nude study by Arnold Genthe
• 
  Original, unused box of Autochrome plates (1921)
• 
  Original, unused box of Autochrome plates (1921) - reverse side, featuring different languages
• 
  Original Autochrome instruction manual - front cover (scan)
• 
  Autochrome Price List pamphlet - front (scan)
• 
  Autochrome Price List pamphlet - reverse (scan)

• Dufaycolor

Wikimedia Commons has media related to Autochromes.

• The Albert Kahn website
• 1907-1935: Universal Polychrome Overview
• Autochrome: Beauty in Colored Pointillism
• Dawn of Colour (includes original instruction booklet (1908)) National Media Museum
• Photographs of World War I in color
• The Albert-Kahn Museum Official Web site (in French)
• Autochromes (including World War I) et al. by Jean-Baptiste Tournassoud (some errors in Autochrome historical information)
• Autochromes from Belgium
• Presentation of Czech Autochrome
• Autochromes from the Mark Jacobs Collection