Colorization

Monochrome images which have been "colorized" by tinting selected areas by hand or mechanically or with the aid of a computer are "colored photographs", not "color photographs". Their colors are not dependent on the actual colors of the objects photographed and may be inaccurate.

The foundation of all practical color processes, the three-color method was first suggested in an 1855 paper by Scottish physicist James Clerk Maxwell, with the first color photograph produced by Thomas Sutton for a Maxwell lecture in 1861.^[1][2] Color photography has been the dominant form of photography since the 1970s, with monochrome photography mostly relegated to niche markets such as art photography.

Three-color processes

Portrait of painter Albert Bierstadt, made by his brother Edward Bierstadt. This collotype print was sent in 1895 to Elbridge T. Gerry. It may be the oldest surviving color portrait photograph.

The three-color method, which is the foundation of most practical color processes, whether chemical or electronic, was first suggested in an 1855 paper on color vision by Scottish physicist James Clerk Maxwell.^[1][2]

In his studies of color vision, Maxwell showed, by using a rotating disk with which he could alter the proportions of visible hue, or gray tone. This could be made by mixing only three pure colors of light – red, green, and blue – in proportions that would stimulate the three types of cells to the same degrees under particular lighting conditions.^[3] Each type of cell by itself did not actually see color but was stimulated. He drew an analogy to black-and-white photography: if three colorless photographs of the same scene were taken through red, green and blue filters, and transparencies ("slides") made from them were projected through the same filters and superimposed on a screen. This would result in a image reproducing not only red, green and blue, but all of the colors in the original scene.^[4]

The first color photograph made according to this method, a set of three monochrome "color separations", was taken by Thomas Sutton in 1861 for use in illustrating a lecture on color by Maxwell, where it was shown in color by the triple projection method.^[5] The test subject was a bow made of ribbon with stripes of various colors, including red and green. During the lecture about physics and physiology, not photography, Maxwell commented on the inadequacy of the results and the need for a photographic material more sensitive to red and green light. A century later, historians were mystified by the reproduction of any red at all because the photographic process used by Sutton was, for all practical purposes, insensitive to red light and only marginally sensitive to green. In 1961, researchers found that many red dyes also reflect ultraviolet light, coincidentally transmitted by Sutton's red filter, and surmised that the three images were probably due to ultra-violet, blue-green, and blue wavelengths, rather than to red, green, and blue.^[6]

Screen-plate era

A color photograph made by Gabriel Lippmann in the 1890s, containing no pigments or dyes of any kind.

The Joly screen process emerged as a simpler and cheaper alternative, requiring no specialized camera or viewer. Instead, it necessitated a unique color-compensating filter for the camera lens and a particular holder for the photographic plates. The core of the system resided within the holder: a clear glass plate meticulously ruled with fine lines of three colors, creating a, repeating pattern across its entire surface. Rather than capturing three separate photographs through individual colored filters, this method employed narrow strips (the colored lines) to allow the essential color information to be recorded in a single, composite image. After developing the negative, a positive transparency was produced, and a viewing screen—with red, green, and blue lines matching the taking screen's pattern—was precisely aligned and applied, rendering the colors visible. The transparency and screen were notably similar to the monochrome liquid crystal elements and overlay of ultra-thin red, green, and blue color filter stripes that generate the color image in a typical LCD display. This invention was attributed to Irish scientist John Joly, who, like many inventors, discovered that the fundamental concept had been preemptively outlined in Louis Ducos du Hauron's 1868 patent, which had since expired.^[7]

Digital photography

This section is an excerpt from Digital photography § History.[edit]

While digital photography has only relatively recently become mainstream, the late 20th century saw many small developments leading to its creation. The history of digital photography began in the 1950s. In 1951, the first digital signals were saved to magnetic tape via the first video tape recorder.^[8] Six years later, in 1957, the first digital image was produced through a computer by Russell Kirsch. It was an image of his son.^[9]

First digital image ever created, by Russell Kirsch. It is an image of his son, Walden.

The first semiconductor image sensor was the charge-coupled device (CCD), invented by physicists Willard S. Boyle and George E. Smith at Bell Labs in 1969.^[10] While researching the metal-oxide semiconductor (MOS) process, they realized that an electric charge was analogous to a magnetic bubble and that the charge could be stored on a tiny MOS capacitor. As it was fairly straightforward to fabricate a series of MOS capacitors in a row, they connected a suitable voltage to the capacitors so that the charge could be stepped along from one to the next.^[11] This semiconductor circuit was later used in the first digital video cameras for television broadcasting,^[12] and its invention was recognized by a Nobel Prize in Physics in 2009.^[13]

The first close-up image of Mars was taken as Mariner 4 flew by it on July 15, 1965, with a digital camera system designed by NASA and JPL. In 1976, the twin Mars Viking Landers produced the first images from the surface of Mars. The imaging process was different from that of a modern digital camera, though the result was similar; Viking used a mechanically scanned facsimile camera rather than a mosaic of solid state sensor elements.^[14] This produced a digital image that was stored on tape for later, relatively slow transmission back to Earth.^[15][16]

The first published color digital photograph was produced in 1972 by Michael Francis Tompsett using CCD sensor technology and was featured on the cover of Electronics Magazine. It was a picture of his wife, Margaret Tompsett.^[17] The Cromemco Cyclops, a digital camera developed as a commercial product and interfaced to a microcomputer, was featured in the February 1975 issue of Popular Electronics magazine. It used MOS technology for its image sensor.

An important development in digital image compression technology was the discrete cosine transform (DCT), a lossy compression technique first proposed by Nasir Ahmed while he was working at the Kansas State University in 1972.^[18] DCT compression is used in the JPEG image standard, which was introduced by the Joint Photographic Experts Group in 1992.^[19] JPEG compresses images down to much smaller file sizes, and has become the most widely used image file format.^[20] The JPEG standard was largely responsible for popularizing digital photography.^[21]

The first self-contained (portable) digital camera was created in 1975 by Steven Sasson of Eastman Kodak.^[22][23] Sasson's camera used CCD image sensor chips developed by Fairchild Semiconductor in 1973.^[24] The camera weighed 8 pounds (3.6 kg), recorded black-and-white images to a cassette tape, had a resolution of 0.01 megapixels (10,000 pixels), and took 23 seconds to capture its first image in December 1975. The prototype camera was a technical exercise, not intended for production.^[25] While it was not until 1981 that the first consumer camera was produced by Sony, the groundwork for digital imaging and photography had been laid.^[26]

The first digital single-lens reflex (DSLR) camera was the Nikon SVC prototype demonstrated in 1986, followed by the commercial Nikon QV-1000C released in 1988.^[27] The first widely commercially available digital camera was the 1990 Dycam Model 1; it also sold as the Logitech Fotoman. It used a CCD image sensor, stored pictures digitally, and connected directly to a computer for downloading images.^[28][29][30] Originally offered to professional photographers for a hefty price, by the mid-to-late 1990s, due to technology advancements, digital cameras were commonly available to the general public.

The advent of digital photography also gave way to cultural changes in the field of photography. Unlike film photography, dark rooms and hazardous chemicals were no longer required for the post-production of an image – images could now be processed and enhanced from a personal computer. This allowed photographers to be more creative with their processing and editing techniques. As the field became more popular, digital photography and photographers diversified. Digital photography expanded the field of photography from a small, somewhat elite circle to one that encompassed many people.^[31]

The camera phone further helped popularize digital photography, along with the Internet, social media,^[32] and the JPEG image format.^[21] The first cell phones with built-in digital cameras were produced in 2000 by Sharp and Samsung.^[33] Small, convenient, and easy to use, camera phones have made digital photography ubiquitous in the daily life of the general public.

The Bayer arrangement of color filters on the pixel array of an image sensor

Proponents

Paul Outerbridge was an American photographer prominent for his early use and experiments in color photography. He began writing a monthly column on color photography for the U.S. Camera Magazine around 1930. Outerbridge became known for the high quality of his color illustrations, made by a highly complex tri-color carbro process.^[34] In 1940 he published his seminal book Photographing in Color, using high quality illustrations to explain his techniques.^[35]

Ferenc Berko, a photographer who lived during the introduction of color film, recognized a potential of color film. He saw it as a way to experiment with the subjects he photographed and how he conveyed emotion in the photograph.^[36]

John Hedgecoe, another photographer who lived during the time period, was another example of those who adopted color photographs. He published a book entitled The Art of Color Photography, which explained the importance of understanding the

Special and often subtle relationships between different colors.

— John Hedgecoe

He also described the psychological and emotional power of color on the viewer since certain colors, he argues, can make people feel a certain way.^[37]

Skeptics

Harold Baquet, for instance—a photographer who lived during the 1980's, known best for documenting New Orleans civil rights—was not keen on color. He preferred to take pictures mainly using black-and-white film. When asked about his reasoning for this preference during an interview, he replied,

The less is more. Sometimes the color distracts from the essential subject. Sometimes, light, line, and form is enough, allowing you to explore the sculptural qualities of that third dimension, that illusional dimension of depth. And it’s fun.

— Harold Baquet

This aversion to color was due mainly to a fear of losing simplicity in his pictures. He worried that color gave the eye too much to take in.^[38]