Misplaced Pages

#293706

86-442: However, the stencil process was not a color photography process and did not use color film stock . Like computer-based film colorization processes, it was a way of arbitrarily adding selected colors to films originally photographed and printed in black-and-white . Each frame of an extra print of the black-and-white film to be colored was rear-projected onto a sheet of frosted glass , as in rotoscoping . An operator used

172-534: A spectral density plot . Antibiotic spectrum of activity is a component of antibiotic classification . A broad-spectrum antibiotic is active against a wide range of bacteria, whereas a narrow-spectrum antibiotic is effective against specific families of bacteria. An example of a commonly used broad-spectrum antibiotic is ampicillin . An example of a narrow spectrum antibiotic is Dicloxacillin , which acts on beta-lactamase -producing Gram-positive bacteria such as Staphylococcus aureus . In psychiatry,

258-457: A blunt stylus to trace the outlines of areas of the projected image that were to be tinted one particular color. The stylus was connected to a reducing pantograph that caused a sharp blade to cut corresponding outlines through the actual film frame, creating the stencil for that color in that frame. This had to be done for each individual frame, and as many different stencil films had to be made as there were different colors to be added. Each of

344-561: A brief period in the early 1930s, the American Agfa-Ansco company produced Colorol, a roll-film tripack for snapshot cameras. The three emulsions were on unusually thin film bases. After exposure, the roll was sent to Agfa-Ansco for processing and the triple negatives were returned to the customer with a set of color prints. The images were not sharp and the color was not very good, but they were genuine "natural color" snapshots. "Bipacks" using only two emulsions face-to-face were

430-462: A depth that depends on the wavelength of the light. Thus, reading light at a lower layer in a silicon stack would yield a different value than reading it at the top, and the difference can be used to compute the color of the light in addition to its intensity. Another option is the use of a prism to separate the colors onto three separate capturing devices, as in a three-CCD camera . Spectrum A spectrum ( pl. : spectra or spectrums )

516-444: A high-quality camera of this type which was commercially introduced by Bermpohl in 1903. It was probably this Miethe-Bermpohl camera which was used by Miethe's pupil Sergei Mikhailovich Prokudin-Gorskii to make his now-celebrated color photographic surveys of Russia before the 1917 revolution. One sophisticated variant, patented by Frederic Eugene Ives in 1897, was driven by clockwork and could be adjusted to automatically make each of

602-423: A highly diffused light source, which causes loss of color saturation and other ill effects due to light scatter within the structure of the screen and emulsion, and by fluorescent or other artificial light which alters the color balance. The capabilities of the process should not be judged by the dull, washed-out, odd-colored reproductions commonly seen. Millions of Autochrome plates were manufactured and used during

688-400: A modification developed by Kodak rather than the original Agfa version. In 1941, Kodak made it possible to order prints from Kodachrome slides. The print "paper" was actually a white plastic coated with a multilayer emulsion similar to that on the film. These were the first commercially available color prints created by the chromogenic dye coupler method. In the following year, Kodacolor film

774-488: A name recycled from an earlier and completely different two-color process. Its development was led by the improbable team of Leopold Mannes and Leopold Godowsky Jr. (nicknamed "Man" and "God"), two highly regarded classical musicians who had started tinkering with color photographic processes and ended up working with the Kodak Research Laboratories. Kodachrome had three layers of emulsion coated on

860-529: A purplish-pink which absorbs green; and yellow, which absorbs blue. The red-filtered image is used to create a cyan dye image, the green-filtered image to create a magenta dye image, and the blue-filtered image to create a yellow dye image. When the three dye images are superimposed they form a complete color image. This is also known as the CMYK color model . The "K" is a black component normally added in ink-jet and other mechanical printing processes to compensate for

946-405: A range of qualities, which are the perceived "colors of the rainbow" and other properties which correspond to wavelengths that lie outside of the visible light spectrum. Spectrum has since been applied by analogy to topics outside optics. Thus, one might talk about the " spectrum of political opinion ", or the "spectrum of activity" of a drug, or the " autism spectrum ". In these uses, values within

SECTION 10

#1732801710294

1032-435: A set of color separations was ultimately required in order to prepare printing plates. The second type, known variously as a multiple back, repeating back or drop back camera, still exposed the images one at a time but used a sliding holder for the filters and plates which allowed each filter and the corresponding unexposed area of emulsion to be quickly shifted into place. German photochemistry professor Adolf Miethe designed

1118-411: A single base, each layer recording one of the three additive primaries, red, green, and blue. In keeping with Kodak's old "you press the button, we do the rest" slogan, the film was simply loaded into the camera, exposed in the ordinary way, then mailed to Kodak for processing. Aside from manufacturing the film, processing was the most complex step. This involved the controlled penetration of chemicals into

1204-437: A special holder for the photographic plates. The holder contained the heart of the system: a clear glass plate on which very fine lines of three colors had been ruled in a regular repeating pattern, completely covering its surface. The idea was that instead of taking three separate complete photographs through three colored filters, the filters could be in the form of a large number of very narrow strips (the colored lines) allowing

1290-437: A spectrum may not be associated with precisely quantifiable numbers or definitions. Such uses imply a broad range of conditions or behaviors grouped together and studied under a single title for ease of discussion. Nonscientific uses of the term spectrum are sometimes misleading. For instance, a single left–right spectrum of political opinion does not capture the full range of people's political beliefs. Political scientists use

1376-407: A tripack did not have to be taken apart in order to produce the cyan, magenta and yellow dye images from them, they could be coated directly on top of each other, eliminating the most serious problems. In fact, some chemical magic was under development which would make that possible. In 1935, American Eastman Kodak introduced the first modern "integral tripack" color film and called it Kodachrome ,

1462-503: A variety of biaxial and multiaxial systems to more accurately characterize political opinion. In most modern usages of spectrum there is a unifying theme between the extremes at either end. This was not always true in older usage. In Latin , spectrum means "image" or " apparition ", including the meaning " spectre ". Spectral evidence is testimony about what was done by spectres of persons not present physically, or hearsay evidence about what ghosts or apparitions of Satan said. It

1548-401: A viewer displaying a still-life subject next to the actual objects photographed, inviting direct comparison. A Kromskop triple "lantern" could be used to project the three images, mounted in a special metal or wooden frame for this purpose, through filters as Maxwell had done in 1861. Prepared Kromograms of still-life subjects, landscapes, famous buildings and works of art were sold and these were

1634-495: A viewing device which used an arrangement of colored glass filters to illuminate each slide with the correct color of light and transparent reflectors to visually combine them into a single full-color image. The most popular model was stereoscopic . By looking through its pair of lenses, an image in full natural color and 3-D was seen, a startling novelty in the late Victorian age. The results won near-universal praise for excellence and realism. At demonstrations, Ives sometimes placed

1720-786: A wider dynamic range and, therefore, of a greater degree of realism than the more convenient medium of prints on paper. The early popularity of color "slides" among amateurs went into decline after automated printing equipment began improving print quality and lowering prices. Other currently available films are designed to produce color negatives for use in creating enlarged positive prints on color photographic paper. Color negatives may also be digitally scanned and then printed by photographic or non-photographic means, or viewed as positives electronically. Unlike reversal-film transparency processes, negative-positive processes are, within limits, forgiving of incorrect exposure and poor color lighting, because printing allows considerable correction. Negative film

1806-465: Is a stub . You can help Misplaced Pages by expanding it . Color photography Color photography is photography that uses media capable of capturing and reproducing colors . By contrast, black-and-white or gray- monochrome photography records only a single channel of luminance (brightness) and uses media capable only of showing shades of gray . In color photography, electronic sensors or light-sensitive chemicals record color information at

SECTION 20

#1732801710294

1892-436: Is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum . The word spectrum was first used scientifically in optics to describe the rainbow of colors in visible light after passing through a prism . As scientific understanding of light advanced, it came to apply to the entire electromagnetic spectrum . It thereby became a mapping of a range of magnitudes (wavelengths) to

1978-447: Is also known as the RGB color model . The same three images taken through red, green and blue filters which are used for additive color synthesis may also be used to produce color prints and transparencies by the subtractive method, in which colors are subtracted from white light by dyes or pigments. In photography, the dye colors are normally cyan, a greenish-blue which absorbs red; magenta,

2064-407: Is the additive method of color reproduction. LCD, LED, plasma and CRT (picture tube) color video displays all use this method. If one of these displays is examined with a sufficiently strong magnifier, it will be seen that each pixel is actually composed of red, green and blue sub-pixels which blend at normal viewing distances, reproducing a wide range of colors as well as white and shades of gray. This

2150-422: Is the use of a Bayer filter , invented by Bryce Bayer of Eastman Kodak in 1976. In this approach, a sensor that is sensitive to multiple wavelengths of light is placed behind a color filter. Traditionally, each pixel, or "sensel", is thereby assigned an additional light response curve beyond its inherent differential response to different wavelengths - typically the filters applied respond to red, blue and green,

2236-401: Is the use of a spectrometer for chemical analysis . In the physical sciences , the term spectrum was introduced first into optics by Isaac Newton in the 17th century, referring to the range of colors observed when white light was dispersed through a prism . Soon the term referred to a plot of light intensity or power as a function of frequency or wavelength , also known as

2322-401: Is therefore more suitable for casual use by amateurs. Virtually all single-use cameras employ negative film. Photographic transparencies can be made from negatives by printing them on special "positive film", but this has always been unusual outside of the motion picture industry and commercial service to do it for still images may no longer be available. Negative films and paper prints are by far

2408-411: The spectrum approach uses the term spectrum to describe a range of linked conditions, sometimes also extending to include singular symptoms and traits . For example, the autism spectrum describes a range of conditions classified as neurodevelopmental disorders . In mathematics , the spectrum of a matrix is the multiset of the eigenvalues of the matrix. In functional analysis, the concept of

2494-478: The spectrum of a bounded operator is a generalization of the eigenvalue concept for matrices. In algebraic topology , a spectrum is an object representing a generalized cohomology theory . In social science , economic spectrum is used to indicate the range of social class along some indicator of wealth or income. In political science , the term political spectrum refers to a system of classifying political positions in one or more dimensions, for example in

2580-402: The "problem" colors could now be reduced from hours to minutes. As ever-more-sensitive gelatin emulsions replaced the old wet and dry collodion processes, the minutes became seconds. New sensitizing dyes introduced early in the 20th century eventually made so-called "instantaneous" color exposures possible. Making color separations by reloading the camera and changing the filter between exposures

2666-406: The 1840s. Early experiments were directed at finding a "chameleon substance" which would assume the color of the light falling on it. Some early results, typically obtained by projecting a solar spectrum directly onto the sensitive surface, seemed to promise eventual success, but the comparatively dim image formed in a camera required exposures lasting for hours or even days. The quality and range of

Pathécolor - Misplaced Pages Continue

2752-773: The Autochrome process quickly rendered the Lippmann method redundant. The method is still utilized to make singular images that cannot be copied for security purposes. The first commercially successful color process, the Lumière Autochrome , invented by the French Lumière brothers , reached the market in 1907. Instead of colored strips, it was based on an irregular screen plate filter made of three colors of dyed grains of potato starch which were too small to be individually visible. The light-sensitive emulsion

2838-601: The Kromskop viewer's usual fodder, but a "multiple back" camera attachment and a set of three specially adjusted color filters could be bought by "Kromskopists" wishing to make their own Kromograms. Kromskops and ready-made Kromograms were bought by educational institutions for their value in teaching about color and color vision, as well as by wealthy individuals. A few people made their own Kromograms. These were not enough to sustain Ives’ businesses, which had been set up to exploit

2924-606: The Lumière Autochrome. The most recent use of the additive screen process for non-digital photography was in Polachrome, an "instant" 35mm slide film introduced in 1983 and discontinued about twenty years later. Louis Ducos du Hauron had suggested using a sandwich of three differently color-recording emulsions on transparent supports which could be exposed together in an ordinary camera, then taken apart and used like any other set of three-color separations. The problem

3010-477: The color image in a typical LCD display. This was the invention of Irish scientist John Joly, although he, like so many other inventors, eventually discovered that his basic concept had been anticipated in Louis Ducos du Hauron's long-since-expired 1868 patent. The Joly screen process had some problems. First and foremost, although the colored lines were reasonably fine (about 75 sets of three colored lines to

3096-468: The color was sometimes limited mainly to primary colors, as in the chemically complicated "Hillotype" process invented by American daguerreotypist Levi Hill around 1850. Other experimenters, such as Edmond Becquerel , achieved better results but could find no way to prevent the colors from quickly fading when the images were exposed to light for viewing. Over the following decades experimentation continued without practical results. The three-color method,

3182-492: The colors. It is similar to using the colors of soap bubbles to make an image. Gabriel Jonas Lippmann won the Nobel Prize in physics in 1908 for the creation of the first color photographic process using a single emulsion. The method is based on the interference phenomenon . The color fidelity is extremely high but the images can not be reproduced and viewing requires very specific lighting conditions. The development of

3268-408: The end of the spectrum called "red", another is sensitive to the middle or "green" region, and the third is sensitive to the "blue" region. The named colors are arbitrary divisions imposed on the continuous spectrum of visible light and the theory is not an entirely accurate description of cone sensitivity. The simple description of these three colors coincides enough with the sensations experienced by

3354-516: The expense (one plate cost about as much as a dozen black-and-white plates of the same size), the relatively long exposure times which made hand-held "snapshots" and photographs of moving subjects impractical, and the density of the finished image due to the presence of the light-absorbing color screen. Viewed under optimum conditions and by daylight as intended, a well-made and well-preserved Autochrome can look startlingly fresh and vivid. Unfortunately, modern film and digital copies are usually made with

3440-421: The exposures for a different length of time according to the particular color sensitivities of the emulsion being used. Otherwise simple cameras with multiple color-filtered lenses were sometimes tried, but unless everything in the scene was at a great distance, or all in a plane at the same distance, the difference in the viewpoints of the lenses ( parallax ) made it impossible to completely register all parts of

3526-456: The eye that when these three colors are used the three cones types are adequately and unequally stimulated to form the illusion of various intermediate wavelengths of light . In his studies of color vision, Maxwell showed, by using a rotating disk with which he could alter the proportions, that any visible hue or gray tone could be made by mixing only three pure colors of light – red, green and blue – in proportions that would stimulate

Pathécolor - Misplaced Pages Continue

3612-619: The final projection prints was matched up with one of the stencil films and run through a machine that applied the corresponding dye through the stencil. This operation was repeated using each of the different stencils and dyes in turn. The Pathécolor stencil process should not be confused with the later Pathécolor, Pathé Color and Color by Pathé (sometimes without the acute accent ) trade names seen in screen credits and advertising materials. Like Metrocolor, WarnerColor and Color by DeLuxe, these were simply rebrandings of Eastman Kodak 's Eastmancolor color negative film. This filmmaking article

3698-471: The first half of the 20th century, some of them short-lived, others, such as the Trichrome Carbro process, enduring for several decades. Because some of these processes allow very stable and light-fast coloring matter to be used, yielding images which can remain virtually unchanged for centuries, they are still not quite completely extinct. The production of photographic three-color prints on paper

3784-464: The foundation of most color processes, chemical or electronic, was first suggested in an 1855 paper on color vision by Scottish physicist James Clerk Maxwell . The method is based on the Young–Helmholtz theory , which states that the human eye sees color using millions of intermingled cone cells of three types on its inner surface. According to the theory, one type of cone is most sensitive to

3870-451: The imperfections of the colored inks used, which ideally should absorb or transmit various parts of the spectrum but not reflect any color, and to improve image definition. At first it may seem that each image ought to be printed in the color of the filter used in making it, but by following any given color through the process the reason for printing in complementary colors should become apparent. A red object, for example, will be very pale in

3956-459: The inch) they were still disturbingly visible at normal viewing distances and nearly intolerable when enlarged by projection. This problem was exacerbated by the fact that each screen was individually ruled on a machine which used three pens to apply the transparent colored inks, resulting in irregularities, high reject rates and high cost. The glass used for photographic plates at the time was not perfectly flat, and lack of uniform good contact between

4042-436: The later SX-70 system, which produced no separate negative to discard. Some currently available color films are designed to produce positive transparencies for use in a slide projector or magnifying viewer, although paper prints can also be made from them. Transparencies are preferred by some professional photographers who use film because they can be judged without having to print them first. Transparencies are also capable of

4128-405: The latter being used twice as often based on an argument that the human eye is more sensitive to variation in green than any other color. Thus, the color image produced would preserve color in a way resembling human perception, and not appear unduly deteriorated in any particular color range. However, alternative approaches do exist. The Foveon sensor uses the fact that light penetrates silicon to

4214-474: The lens into three parts, each part passing through a different color filter and forming a separate image, so that the three images could be photographed at the same time on three plates (flexible film had not yet replaced glass plates as the support for the emulsion) or different areas of one plate. Later known as "one-shot" cameras, refined versions continued to be used as late as the 1950s for special purposes such as commercial photography for publication, in which

4300-456: The most common form of color film photography today. After a transition period centered around 1994–2006, color film was relegated to a niche market by inexpensive multi-megapixel digital cameras that can shoot both in monochrome as well as color. Some photographers continue to prefer film for its distinctive "look" for artistic purposes or out of fondness. The most commonly used method of obtaining color information in digital photography

4386-504: The necessary color information to be recorded in a single compound image. After the negative was developed, a positive transparency was printed from it and a viewing screen with red, green and blue lines in the same pattern as the lines of the taking screen was applied and carefully aligned. The colors then appeared as if by magic. The transparency and screen were very like the layer of monochrome liquid crystal elements and overlay of hair-thin red, green and blue color filter stripes which create

SECTION 50

#1732801710294

4472-511: The norm for snapshot-taking in most families. Black-and-white film continued to be used by some photographers who preferred it for aesthetic reasons or who wanted to take pictures by existing light in low-light conditions, which was still difficult to do with color film. They usually did their own developing and printing. By 1980, black-and-white film in the formats used by typical snapshot cameras, as well as commercial developing and printing service for it, had nearly disappeared. Instant color film

4558-447: The norm. By 1960, color was much more common but still tended to be reserved for travel photos and special occasions. Color film and color prints cost several times as much as black-and-white, and taking color snapshots in deep shade or indoors required flashbulbs —an inconvenience and an additional expense. By 1970, prices were dropping, film sensitivity had improved, electronic flash units were replacing flashbulbs, and color had become

4644-413: The optical systems involved, and in simplifying the apparatus to bring down the cost of producing it commercially. The color images, dubbed "Kromograms", were in the form of sets of three black-and-white transparencies on glass, mounted onto special cloth-tape-hinged triple cardboard frames. To see a Kromogram in color it had to be inserted into a "Kromskop" (generic name "chromoscope" or "photochromoscope"),

4730-508: The photographic process used by Sutton was for all practical purposes totally 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. Creating colors by mixing colored lights (usually red, green and blue) in various proportions

4816-515: The previously ineffective colors except true red, to which only a marginal trace of sensitivity could be added. In the following year, Edmond Becquerel discovered that chlorophyll was a good sensitizer for red. Although it would be many more years before these sensitizers (and better ones developed later) found much use beyond scientific applications such as spectrography, they were quickly and eagerly adopted by Louis Ducos du Hauron, Charles Cros and other color photography pioneers. Exposure times for

4902-463: The primary colors of light with color reversal. As long as photographic materials were usefully sensitive only to blue-green, blue, violet and ultraviolet, three-color photography could never be practical. In 1873 German chemist Hermann Wilhelm Vogel discovered that the addition of small amounts of certain aniline dyes to a photographic emulsion could add sensitivity to colors which the dyes absorbed. He identified dyes which variously sensitized for all

4988-461: The public. The most extensive and expensive of the two was the "Kromskop" (pronounced "chrome-scope") system developed by Frederic Eugene Ives . This was a straightforward additive system and its essential elements had been described by James Clerk Maxwell, Louis Ducos du Hauron and Charles Cros much earlier, but Ives invested years of work and ingenuity in refining the methods and materials to optimize color quality, in overcoming problems inherent in

5074-430: The quarter century before the plates were replaced by film-based versions in the 1930s. The very last film version, named Alticolor, brought the Autochrome process into the 1950s but was discontinued in 1955. Many additive color screen products were available between the 1890s and the 1950s, but none, with the possible exception of Dufaycolor , introduced as film for still photography in 1935, was as popular or successful as

5160-475: The red or orange-filtered negative requiring hours of exposure in the camera. His earliest surviving color prints are "sun prints" of pressed flowers and leaves, each of the three negatives having been made without a camera by exposing the light-sensitive surface to direct sunlight passing first through a color filter and then through the vegetation. His first attempts were based on the red-yellow-blue colors then used for pigments, with no color reversal. Later he used

5246-462: The red, green and blue which are present in white light ( CMY color , used for prints on paper and transparencies on film). 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,

SECTION 60

#1732801710294

5332-421: The red-filtered image but very dark in the other two images, so the result will be an area with just a trace of cyan, absorbing just a bit of red light, but a large amount of magenta and yellow, which together absorb most of the green and blue light, leaving mainly red light to be reflected back from the white paper in the case of a print, or transmitted through a clear support in the case of a transparency. Before

5418-405: The resulting images at the same time. Prior to the late 1890s color photography was strictly the domain of a very few experimenters willing to build their own equipment, do their own color-sensitizing of photographic emulsions, make and test their own color filters and otherwise devote a large amount of time and effort to their pursuits. There were many opportunities for something to go wrong during

5504-406: The same filters and superimposed on a screen, the result would be an image reproducing not only red, green and blue, but all of the colors in the original scene. The first color photograph made according to Maxwell's prescription, 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

5590-604: The screen and the image gave rise to areas of degraded color. Poor contact also caused false colors to appear if the sandwich was viewed at an angle. Although much simpler than the Kromskop system, the Joly system was not inexpensive. The starter kit of plate holder, compensating filter, one taking screen and one viewing screen cost US$ 30 (the equivalent of at least $ 750 in 2010 dollars) and additional viewing screens were $ 1 each (the equivalent of at least $ 25 in 2010 dollars). This system, too, soon died of neglect, although in fact it pointed

5676-558: The series of operations required and problem-free results were rare. Most photographers still regarded the whole idea of color photography as a pipe dream, something only madmen and swindlers would claim to have accomplished. In 1898, however, it was possible to buy the required equipment and supplies ready-made. Two adequately red-sensitive photographic plates were already on the market, and two very different systems of color photography with which to use them, described in photographic magazines for several years prior, were finally available to

5762-514: The sharpest image. The two layers behind it, one sensitized to red but not green and the other to green but not red, would suffer from scattering of the light as it passed through the topmost emulsion, and one or both would further suffer by being spaced away from it. Despite these limitations, some "tripacks" were commercially produced, such as the Hess-Ives "Hiblock" which sandwiched an emulsion on film between emulsions coated on glass plates. For

5848-425: The subject of some development. Although the range of colors which could be reproduced by only two components was limited, skin tones and most hair and eye colors could be rendered with surprising fidelity, making bipack processes a viable option for color portraiture. In commercial practice, however, the use of bipacks was almost entirely confined to two-color motion picture systems. If the three layers of emulsion in

5934-528: The system; they soon failed, but the viewers, projectors, Kromograms and several varieties of Kromskop cameras and camera attachments continued to be available through the Scientific Shop in Chicago as late as 1907. The simpler and somewhat more economical alternative was the Joly screen process. This required no special camera or viewer, just a special color-compensating filter for the camera lens and

6020-461: The technical innovations of the years 1935 to 1942, the only way to create a subtractive full-color print or transparency was by means of one of several labor-intensive and time-consuming procedures. Most commonly, three pigment images were first created separately by the so-called carbon process and then carefully combined in register. Sometimes, related processes were used to make three gelatin matrices which were dyed and assembled or used to transfer

6106-446: The three dye images into a single layer of gelatin coated on a final support. Chemical toning could be used to convert three black-and-white silver images into cyan, magenta and yellow images which were then assembled. In a few processes, the three images were created one on top of another by repeated coating or re-sensitizing, negative registration, exposure and development operations. A number of variations were devised and marketed during

6192-404: The three layers of emulsion. A simplified description of the process is as follows: as each layer was developed into a black-and-white silver image, a " dye coupler " added during that stage of development caused a cyan, magenta or yellow dye image to be created along with it. The silver was chemically removed, leaving only the three layers of dye images in the finished film. Initially, Kodachrome

6278-413: The three types of cells to the same degrees under particular lighting conditions. To emphasize that each type of cell by itself did not actually see color but was simply more or less 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

6364-416: 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. Color photography has been the dominant form of photography since the 1970s, with monochrome photography mostly relegated to niche markets such as fine art photography . Color photography was attempted beginning in

6450-533: The time of exposure . This is usually done by analyzing the spectrum of colors into three channels of information, one dominated by red, another by green and the third by blue, in imitation of the way the normal human eye senses color . The recorded information is then used to reproduce the original colors by mixing various proportions of red, green and blue light ( RGB color , used by video displays, digital projectors and some historical photographic processes), or by using dyes or pigments to remove various proportions of

6536-438: The triple projection method. The test subject was a bow made of ribbon with stripes of various colors, apparently including red and green. During the lecture, which was 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

6622-406: The way to the future. Surviving examples of the Joly process usually show extremely poor color now. The colors in the viewing screens have badly faded and shifted, making it impossible to judge their original appearance. In some specimens the viewing screen is also misaligned. Lippmann photography is a way of making a color photograph that relies on Bragg reflection planes in the emulsion to make

6708-531: Was available only as 16mm film for home movies, but in 1936 it was also introduced as 8mm home movie film and short lengths of 35mm film for still photography. In 1938, sheet film in various sizes for professional photographers was introduced, some changes were made to cure early problems with unstable colors, and a somewhat simplified processing method was instituted. In 1936, the German Agfa followed with their own integral tripack film, Agfacolor Neu , which

6794-411: Was coated directly onto the screen plate, eliminating problems due to imperfect contact between the screen and image. Reversal processing was used to convert the negative image which was initially produced into a positive image by removing the exposed silver metal, and re-exposing the remaining silver halide, so no printing or screen registration was required. The shortcomings of the Autochrome process were

6880-418: Was generally similar to Kodachrome but had one important advantage: Agfa had found a way to incorporate the dye couplers into the emulsion layers during manufacture, allowing all three layers to be developed at the same time and greatly simplifying the processing. Most modern color films, excepting the now-discontinued Kodachrome, use the incorporated dye coupler technique, but since the 1970s nearly all have used

6966-400: Was inconvenient, added delays to the already long exposure times and could result in the camera being accidentally shifted out of position. To improve the actual picture-taking, a number of experimenters designed one or more special cameras for color photography. They were usually of two main types. The first type used a system of partially reflecting surfaces to divide the light coming through

7052-552: Was introduced by Polaroid in 1963. Like Polaroid's contemporary instant black-and-white film, their first color product was a negative-positive peel-apart process which produced a unique print on paper. The negative could not be reused and was discarded. The blight created by carelessly discarded caustic-chemical-laden Polaroid negatives, which tended to accumulate most heavily at the prettiest, most snapshot-worthy locations, horrified Polaroid founder Edwin Land and prompted him to develop

7138-493: Was introduced. Unlike Kodachrome, it was designed to be processed into a negative image which showed not only light and dark reversed but also complementary colors. The use of such a negative for making prints on paper simplified the processing of the prints, reducing their cost. The expense of color film as compared to black-and-white and the difficulty of using it with indoor lighting combined to delay its widespread adoption by amateurs. In 1950, black-and-white snapshots were still

7224-485: Was pioneered by Louis Ducos du Hauron , whose comprehensive 1868 French patent also included the basic concepts of most of the color photographic processes which were subsequently developed. For making the three color-filtered negatives required, he was able to develop materials and methods which were not as completely blind to red and green light as those used by Thomas Sutton in 1861, but they were still very insensitive to those colors. Exposure times were impractically long,

7310-448: Was that although two of the emulsions could be in contact face-to-face, the third would have to be separated by the thickness of one transparent support layer. Because all silver halide emulsions are inherently sensitive to blue, the blue-recording layer ought to be on top and have a blue-blocking yellow filter layer behind it. This blue-recording layer, used to make the yellow print which could most afford to be "soft", would end up producing

7396-493: Was used to convict a number of persons of witchcraft at Salem, Massachusetts in the late 17th century. The word "spectrum" [Spektrum] was strictly used to designate a ghostly optical afterimage by Goethe in his Theory of Colors and Schopenhauer in On Vision and Colors . The prefix "spectro-" is used to form words relating to spectra. For example, a spectrometer is a device used to record spectra and spectroscopy

#293706