In 1931, the confusion and ambiguity in color led the Commission Internationale de l’Eclairage (also known as the CIE, or the International Commission on Illumination), to derive a three-dimensional color space from color-matching experiments using a small group of volunteer observers. This by no means was the first attempt at modeling color space, just the first standard that allowed us to calculate whether two spectral distributions have matching color. A little more than 100 years earlier, in 1810, the German painter-theorist Philipp Otto Runge, a Romantic artist and admirer of Newton’s handiwork, made one of the earliest attempts to coordinate hues and values (light and dark content) into a coherent whole by using red, blue and yellow as primaries in a three-dimensional color space rendering, which he titled simply Colour Sphere. Some 50-odd years later, the brilliant British mathematician and physicist James Maxwell, after correctly theorizing that Saturn’s rings consisted of particles, conducted Rumford Medalwinning investigations into the classification of colors and color-blindness. His color-classification system denoted colors in terms of hue, intensity, brightness and tint. (Early color television sets ended up with similar controls.)
The CIE based their additive CIE XYZ color-space model, also known as CIE 1931, on Maxwell’s work, which used the additive color mixture of red, green and blue primaries (see diagram). X, Y and Z define the primary colors in virtual 3-D space (like XYZ axes), with the locus of spectral colors forming a conical horseshoe shape that diminishes toward the rear to the point of black (at X=Y=Z=0) a shape resembling the shell of the Hollywood Bowl if viewed from a 45-degree angle (see diagram). The model represents all colors in the visible spectrum, and colorimetric spaces are always three-dimensional.
Really, the fault lies with Maxwell for setting the stage for eventual color-space clashes in motion pictures and television. In 1861, Maxwell, who actually is recognized more for his work in electromagnetism, stood before his learned colleagues at the Royal Society of London and demonstrated that any shade of colored light could be produced by combining various amounts of red, green and blue-violet: the additive color process. He used three lanterns and placed colored solutions before the lens of each. For his grand finale, he only happened to show the first color photograph. He had chosen a tartan ribbon as his subject, probably because he was a Scotsman, and had photographer Thomas Sutton photograph it three times once with a red filter on the lens, once with a green and once with a blue using wet collodion plates. At the Royal Society, Maxwell placed those primary filters on the three lanterns and projected the plates onto a screen. He then lined the three images up so they overlapped properly, producing one image with somewhat unnatural colors because, unbeknownst to Maxwell, photographic emulsions at that time were not sensitive to red and green light meaning the red- and green-filtered photographs were not true records, unlike the blue-filtered photograph. But there on the screen a color image was projected. (And Maxwell didn’t even charge admission.)
In 1889, George Eastman introduced a transparent celluloid roll to replace the fragile paper rolls in the Kodak camera he had designed a year earlier. Those interested in motion photography latched onto the new base for its thinness and flexibility. Naturally, one would assume that black-and-white dominated the early motion pictures. (It had to, because that was the only film stock available.) However, attempts to colorize the black-and-white imagery in both still and motion-picture photography were being attempted from the get-go. In fact, the first film made for screen projection was in color. In 1894, Annabelle’s Butterfly Dance wasn’t like one of Thomas Edison’s 5-cent Kinetoscope peep shows; it was to be seen by a mass audience (well, at least by more than one person at a time). A product of American inventor C. Francis Jenkins, the short movie simply depicted dancer Annabelle Moore fluttering about in a long, flowing white dress. Frame by frame, the film was hand-tinted to make Annabelle appear to be dancing under colored lights. Apparently, Annabelle was a hit, because seven sequels were spawned.
Jenkins was a busy innovator. In 1895, he and his partner, Thomas Armat, invented the phantoscope, a superior projector in its day, but lost their shirts at the Cotton States and International Exposition in Atlanta, Georgia. Fairgoers turned their noses up at a technology they had never heard of at a steep cost of 25 cents per admission. The phantoscope ended up in the hands of Edison for pocket change. He turned around and manufactured it under the name Vitascope, making a tidy fortune. Jenkins also was a founder and the first president of the Society of Motion Picture Engineers (SMPE); created “radiovision,” which first transmitted images over radio waves for public viewing in 1925; and constructed and managed a radiovision transmitter the first television station, W3XK near Washington, D.C. In 1947, he was presented with a Special Academy Award for his significant contributions to the industry.
Hand-tinting long films was a difficult task, and audiences were becoming annoyed with the fact that tinters could not color within the lines. The French company Pathé streamlined the process in an assembly-line fashion they called the Pathécolor stencil process, and it was performed entirely by women because they had smaller hands. The film was rear-projected onto a ground-glass screen with a stencil overlay, and certain areas were cut out. The stencil and the film were registered and run through a staining machine. A velvet loop saturated with dye applied the color, which reached the film through the holes. As many as six colors were applied, requiring multiple passes (see diagram).
Modeling a color space for the tinting method would produce a very narrow gamut that probably shifted on a per dye-per film basis, and perhaps per frame. Still, it was color and a wider space than black-and-white, which had the narrowest of color spaces: a straight line of grays stretching from the white point to the black point. Tinting was around for awhile. Cecil B. DeMille painted a heart red in his 1922 film Fool’s Paradise, and Sergei Eisenstein painted a flag red and the sky blue for a sequence in his 1925 epic The Battleship Potemkin.
Toning was a method of giving an overall color cast to a scene or full-length film. A kind of forefather of the traditional photochemical timing method, toning required the film to sit in a chemical bath. The types of chemicals determined the color, and the amount of time determined intensity. Toning met with a hasty demise when sound on film became de rigueur the chemicals destroyed the variable-density soundtracks.
Developers, cinematographers, and other experts knew that natural color films would be the way of the future for motion pictures (natural color meaning that the colors would either exist in the film stock or be added by optical or mechanical means). The result would be a more realistically colored image. Still photographers were already enjoying the advantages of three-color RGB film. In 1877, Louis Ducos du Haron, considered the father of photo colors, made the earliest natural color photograph on record, also by using the collodion process. However, the glass plate had an RGB additive-color network engraved onto it.
A number of RGB additive color processes were developed for motion pictures during its early years. Though the processes were natural color, they were beset with problems inherent to film. Sequential RGB processes photographed red-, green- and blue-filtered images successively via a rotating color wheel on the camera (see diagram). When projected, the red, green and blue frames took advantage of the latent-image aspect of a human’s persistence of vision, whereby the mind combined the images into a single color image. However, if a subject moved even the slightest bit, those three frames were not exact and color fringing occurred, causing red, green or blue halos around the subject. Furthermore, the inherently unsteady movement of film virtually guaranteed color fringing, whether the subject moved or not. The additive processes that depended on separate projectors combining to form a color image onscreen, à la James Maxwell, also were prone to fringing because of the films’ shifting movements within the gate.