Tag Archives: Color

Red color in history and art

Red is the color at the end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and the CMYK color model, and is the complementary color of cyan. Reds range from the brilliant yellow-tinged scarlet and vermillion to bluish-red crimson, and vary in shade from the pale red pink to the dark red burgundy. The red sky at sunset results from Rayleigh scattering, while the red color of the Grand Canyon and other geological features is caused by hematite or red ochre, both forms of iron oxide. Iron oxide also gives the red color to the planet Mars. The red colour of blood comes from protein hemoglobin, while ripe strawberries, red apples and reddish autumn leaves are colored by anthocyanins. Red pigment made from ochre was one of…

Green color in history and art

Green is the color between blue and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495–570 nm. In subtractive color systems, used in painting and color printing, it is created by a combination of yellow and blue, or yellow and cyan; in the RGB color model, used on television and computer screens, it is one of the additive primary colors, along with red and blue, which are mixed in different combinations to create all other colors. By far the largest contributor to green in nature is chlorophyll, the chemical by which plants photosynthesize and convert sunlight into chemical energy. Many creatures have adapted to their green environments by taking on a green hue themselves as camouflage. Several minerals have a green color, including the emerald, which is colored green by its chromium content. During post-classical and early modern Europe, green was…

Blue colour in history and art

Blue is one of the three primary colours of pigments in painting and traditional colour theory, as well as in the RGB colour model. It lies between violet and green on the spectrum of visible light. The eye perceives blue when observing light with a dominant wavelength between approximately 450 and 495 nanometres. Most blues contain a slight mixture of other colors; azure contains some green, while ultramarine contains some violet. The clear daytime sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering. An optical effect called Tyndall scattering explains blue eyes. Distant objects appear more blue because of another optical effect called atmospheric perspective. Blue has been an important colour in art and decoration since ancient times. The semi-precious stone lapis lazuli was used in ancient Egypt for jewellery and ornament and later, in the Renaissance, to make the pigment ultramarine, the…

White color in history and art

White is the lightest color and is achromatic (having no hue), because it fully reflects and scatters all the visible wavelengths of light. It is the color of fresh snow, chalk, and milk, and is the opposite of black. In ancient Egypt and ancient Rome, priestesses wore white as a symbol of purity, and Romans wore a white toga as a symbol of citizenship. In the Middle Ages and Renaissance a white unicorn symbolized chastity, and a white lamb sacrifice and purity. It was the royal color of the Kings of France, and of the monarchist movement that opposed the Bolsheviks during the Russian Civil War (1917–1922). Greek and Roman temples were faced with white marble, and beginning in the 18th century, with the advent of neoclassical architecture, white became the most common color of new churches, capitols and other government buildings, especially in the United States. It was also…

Gray Color in history and art

Gray is an intermediate color between black and white. It is a neutral or achromatic color, meaning literally that it is a color “without color.” It is the color of a cloud-covered sky, of ash and of lead. The first recorded use of grey as a color name in the English language was in AD 700. Grey is the dominant spelling in European and Commonwealth English, although gray remained in common usage in the UK until the second half of the 20th century. Gray has been the preferred American spelling since approximately 1825, although grey is an accepted variant. In Europe and the United States, surveys show that grey is the color most commonly associated with neutrality, conformity, boredom, uncertainty, old age, indifference, and modesty. Only one percent of respondents chose it as their favorite color. In history and art Antiquity through the Middle Ages In antiquity and the Middle…

Black color in history and art

Black is the darkest color, the result of the absence or complete absorption of visible light. It is an achromatic color, literally a color without hue, like white (its opposite) and gray. It is often used symbolically or figuratively to represent darkness, while white represents light. Black ink is the most common color used for printing books, newspapers and documents, because it has the highest contrast with white paper and is the easiest to read. For the same reason, black text on a white screen is the most common format used on computer screens. In color printing it is used along with the subtractive primaries cyan, yellow, and magenta, in order to help produce the darkest shades. Black and white have often been used to describe opposites; particularly truth and ignorance, good and evil, the “Dark Ages” versus Age of Enlightenment. Since the Middle Ages black has been the symbolic…

Polychrome

Polychrome is the “practice of decorating architectural elements, sculpture, etc., in a variety of colors.” The term is used to refer to certain styles of architecture, pottery or sculpture in multiple colors. Classical world Some very early polychrome pottery has been excavated on Minoan Crete such as at the Bronze Age site of Phaistos. In ancient Greece sculptures were painted in strong colors. The paint was frequently limited to parts depicting clothing, hair, and so on, with the skin left in the natural color of the stone. But it could cover sculptures in their totality. The painting of Greek sculpture should not merely be seen as an enhancement of their sculpted form but has the characteristics of a distinct style of art. For example, the pedimental sculptures from the Temple of Aphaia on Aegina have recently[when?] been demonstrated to have been painted with bold and elaborate patterns, depicting, amongst other…

Color-blocking

Color-blocking is thought of as the exploration of taking colors that are opposites on the color wheel and pairing them together to make interesting and complementary color combinations. It is commonly associated in fashion as a trend that originated from the artwork of Dutch painter, Piet Mondrian. However, other experts argue whether his artwork is the true origin of color-blocking. History It’s widely believed by most historians that Piet Mondrian, a turn-of-the-century artist, whose paintings were a collection of stark lines and flat squares, inspired this current color-blocking trend. Mondrian valued simplicity and therefore experimented with how far he could simplify his work, maximizing simplicity while still maintaining recognizable, although abstract, geometric shapes. Mondrian later named this style of painting Neo-Plasticism. In Piet Mondrian’s Neoplasticism movement, his art directly inspired the fashion world, as well as home décor and baked goods. Although Mondrian is said to be the key figure…

Spectral color

A spectral color is a color that is evoked in a normal human by a single wavelength of light in the visible spectrum, or by a relatively narrow band of wavelengths, also known as monochromatic light. Every wavelength of visible light is perceived as a spectral color, in a continuous spectrum; the colors of sufficiently close wavelengths are indistinguishable. The spectrum is often divided into named colors, though any division is somewhat arbitrary: the spectrum is continuous. Traditional colors in English include: red, orange, yellow, green, blue, and violet. In some other languages the ranges corresponding to color names do not necessarily agree with those in English. The division used by Isaac Newton, in his color wheel, was: red, orange, yellow, green, blue, indigo and violet; a mnemonic for this order is “Roy G. Biv”. In modern divisions of the spectrum, indigo is often omitted. One needs at least trichromatic…

Windows Color System

Windows Color System (WCS) is a platform for color management, first included with Windows Vista, that aims to achieve color consistency across various software and hardware, including cameras, monitors, printers and scanners. Different devices interpret the same colors differently, according to their software and hardware configurations. As a result, they must be properly calibrated to reproduce colors consistently across different devices. WCS aims to make this process of color calibration automatic and transparent, as an evolution of ICC profiles. Windows Color System features a Color Infrastructure and Translation Engine (CITE) at its core. It is backed up by a color processing pipeline that supports bit-depths more than 32 bits per pixel, multiple color channels (more than three), alternative color spaces and high dynamic range coloring, using a technology named Kyuanos developed by Canon. The color processing pipeline allows device developers to add their own gamut mapping algorithm into the pipeline…

Whiteness

In colorimetry, whiteness is the degree to which a surface is white. An example of its use might be to quantitatively compare two pieces of paper which appear white viewed individually, but not when juxtaposed. The International Commission on Illumination describes it in the following terms: To promote uniformity of practice in the evaluation of whiteness of surface colors, it is recommended that the formulæ for whiteness, W2 or W10, and for tint, Tw,2 or Tw,10, given below, be used for comparisons of the whiteness of samples evaluated for CIE standard illuminant D65. The application of the formulae is restricted to samples that are called “white” commercially, that do not differ much in color and fluorescence, and that are measured on the same instrument at nearly the same time. Within these restrictions, the formulæ provide relative, but not absolute, evaluations of whiteness, that are adequate for commercial use, when employing…

White point

A white point (often referred to as reference white or target white in technical documents) is a set of tristimulus values or chromaticity coordinates that serve to define the color “white” in image capture, encoding, or reproduction. Depending on the application, different definitions of white are needed to give acceptable results. For example, photographs taken indoors may be lit by incandescent lights, which are relatively orange compared to daylight. Defining “white” as daylight will give unacceptable results when attempting to color-correct a photograph taken with incandescent lighting. Illuminants An illuminant is characterized by its relative spectral power distribution (SPD). The white point of an illuminant is the chromaticity of a white object under the illuminant, and can be specified by chromaticity coordinates, such as the x, y coordinates on the CIE 1931 chromaticity diagram (hence the use of the relative SPD and not the absolute SPD, because the white point…

Unique hues

Unique hue is a term used in certain theories of color vision, which implies that human perception distinguishes between “unique” (psychologically primary) and composite (mixed) hues. A unique hue is defined as a color which an observer perceives as a pure, without any admixture of the other colors. There is a great deal of variability when defining unique hues experimentally. Often the results show a great deal of interobserver and intraobserver variability leading to much debate on the number of unique hues. Another source of variability is environmental factors in color naming. Despite the inconsistencies, often four color perceptions are associated as unique; “red”, “green”, “blue”, and “yellow”. History Hering’s opponent process theory The need for certain hues to be designated as unique came with the advent of Opponent process theory. Ewald Hering first proposed the idea that red, green, blue, and yellow were unique in 1892. His theory suggests…

Type color

Type color is an element of typography that describes how dense or heavy the text appears on the page. Finding the correct balance of type color and white space can make text more easily readable. The term type color should not be confused with the usual meaning of color, (i.e. red, yellow, blue), instead it has more to do with the blackness or boldness of the text on the page. A bold font creates more contrast on the page, therefore creates more emphasis. Using a bold font is therefore one way that type color can be adjusted. There are four different decisions a typographer can make that affect the type color. These are the letter spacing, the way the specific font or type is designed, word spacing, and line spacing (leading). Text will appear darker or blacker if the letters are kerned more closely, or if there is less spacing…

Beer color standard reference method

The Standard Reference Method or SRM is one of several systems modern brewers use to specify beer color. Determination of the SRM value involves measuring the attenuation of light of a particular wavelength (430 nm) in passing through 1 cm of the beer, expressing the attenuation as an absorption and scaling the absorption by a constant (12.7 for SRM; 25 for EBC). The SRM (or EBC) number represents a single point in the absorption spectrum of beer. As such it cannot convey full color information which would require 81 points, but it does remarkably well in this regard (it conveys 92% of spectral information) even when fruit beers are considered. Auxiliary “deviation coefficients” (see Augmented SRM below) can pick up the remainder and are necessary for fruit beers and when subtle color differences in malt beers are to be characterized. Measurement method The ASBC and EBC measurements are now identical…

Standard illuminant

A standard illuminant is a theoretical source of visible light with a profile (its spectral power distribution) which is published. Standard illuminants provide a basis for comparing images or colors recorded under different lighting. CIE illuminants The International Commission on Illumination (usually abbreviated CIE for its French name) is the body responsible for publishing all of the well-known standard illuminants. Each of these is known by a letter or by a letter-number combination. Illuminants A, B, and C were introduced in 1931, with the intention of respectively representing average incandescent light, direct sunlight, and average daylight. Illuminants D represent phases of daylight, Illuminant E is the equal-energy illuminant, while Illuminants F represent fluorescent lamps of various composition. There are instructions on how to experimentally produce light sources (“standard sources”) corresponding to the older illuminants. For the relatively newer ones (such as series D), experimenters are left to measure to profiles…

Spectral sensitivity

Spectral sensitivity is the relative efficiency of detection, of light or other signal, as a function of the frequency or wavelength of the signal. In visual neuroscience, spectral sensitivity is used to describe the different characteristics of the photopigments in the rod cells and cone cells in the retina of the eye. It is known that the rod cells are more suited to scotopic vision and cone cells to photopic vision, and that they differ in their sensitivity to different wavelengths of light. It has been established that the maximum spectral sensitivity of the human eye under daylight conditions is at a wavelength of 555 nm, while at night the peak shifts to 507 nm. In photography, film and sensors are often described in terms of their spectral sensitivity, to supplement their characteristic curves that describe their responsivity. A database of camera spectral sensitivity is created and its space analyzed.…

Relative luminance

Relative luminance follows the photometric definition of luminance, but with the values normalized to 1 or 100 for a reference white. Like the photometric definition, it is related to the luminous flux density in a particular direction, which is radiant flux density weighted by the luminosity function y(λ) of the CIE Standard Observer. The use of relative values is useful in systems where absolute reproduction is impractical. For example, in prepress for print media, the absolute luminance of light reflecting off the print depends on the illumination and therefore absolute reproduction cannot be assured. Relative luminance in colorimetric spaces For color spaces such as XYZ, xyY, etc. the letter Y refers to relative luminance. No computation is required to find relative luminance when it is explicit in a color representation in such spaces. For RGB color spaces that use the ITU-R BT.709 primaries (or sRGB, which defines the same primaries),…

Pentachromacy

Pentachromacy describes the capability and capacity for capturing, transmitting, processing, and perceiving five independent channels of color information through the primary visual system. Organisms with pentachromacy are termed pentachromats. For these organisms, it would take at least five differing ranges of wavelengths along the electromagnetic spectrum to reproduce their full visual spectrum. In comparison, a combination of red, green, and blue wavelengths of light are all that is necessary to simulate most of the common human trichromat visual spectrum. One proposed explanation for pentachromacy is a retina containing five distinct types of cone cells with differing absorption spectra. In actuality the number of cone cell types may be greater than five as different types may be active at a specific intensity or range of intensities for a given wavelength of electromagnetic radiation. Animals that are potentially pentachromats Some birds (notably pigeons) and butterflies have five or more kinds of color…

Opponent process

The color opponent process is a color theory that states that the human visual system interprets information about color by processing signals from cones and rods in an antagonistic manner. The three types of cones (L for long, M for medium and S for short) have some overlap in the wavelengths of light to which they respond, so it is more efficient for the visual system to record differences between the responses of cones, rather than each type of cone’s individual response. The opponent color theory suggests that there are three opponent channels: red versus green, blue versus yellow, and black versus white (the last type is achromatic and detects light-dark variation, or luminance). Responses to one color of an opponent channel are antagonistic to those to the other color. That is, opposite opponent colors are never perceived together – there is no “greenish red” or “yellowish blue”. While the…

Oil droplet

Oil droplets are found in the eyes of some animals, being located in the photoreceptor cells. They are especially common in the eyes of diurnal (active during the day) reptiles (e.g. lizards, turtles) and birds (see bird vision), though are present in other taxa such as lungfish. They are found in cone cells far more often than in rods, suggesting a role in colour vision. Occurrence in rod cells may imply that they have been modified from a cone cell ancestor. They occasionally occur in double cones/double rods. Some oil droplets are coloured, while others appear colourless. They are located in the cone inner segment, where they intercept and filter light before it can pass through to the cone outer segment where the visual pigment is. The adaptive advantage of oil droplets is not firmly established. Coloured oil droplets have a cost in that they reduce the amount of light…

Obangsaek

The traditional Korean color spectrum, also known as Obangsaek (오방색), is the color scheme of the five Korean traditional colors of white, black, blue, yellow and red. In Korean traditional arts and traditional textile patterns, the colors of Obangsaek represent five cardinal directions: Blue: east Red: south Yellow: center White: west Black: north These colors are also associated with the Five Elements of traditional Korean culture: Blue: Wood Red: Fire Yellow: Earth White: Metal Black: Water Source From Wikipedia…

Newton disc

The Newton disc is a well-known physics experiment with a rotating disc with segments in different colors (usually Newton’s primary colors: red, orange, yellow, green, blue, indigo, and violet) appearing as white (or off-white or gray) when it spins very fast. This type of mix of light stimuli is called temporal optical mixing, a version of additive-averaging mixing. Many modern sources state that Isaac Newton himself used a disc with colored sectors to demonstrate how white light was actually the compound of the primary colors. However, none seem to refer to a historical source for this. Ptolemy and Ibn al-Haytham described additive optical mixing with turning wheels and spinning tops hundreds of years before Newton, but they did not use primary colors to get the (off-)white result of the Newton disc. Transparent variations for magic lantern projection have been produced. History Around CE 165 Ptolemy described in his book Optics…

Neugebauer equations

The Neugebauer equations are a set of equations used to model color printing systems, developed by Hans E. J. Neugebauer. They were intended to predict the color produced by a combination of halftones printed in cyan, magenta, and yellow inks. The equations estimate the reflectance (in CIE XYZ coordinates or as a function of wavelength) as a function of the reflectance of the 8 possible combinations of CMY inks (or the 16 combinations of CMYK inks), weighted by the area they take up on the paper. In wavelength form: where Ri(λ) is the reflectance of ink combination i, and wi is the relative proportions of the 16 colors in a uniformly colored patch. The weights are dependent on the halftone pattern and possibly subject to various forms of dot gain. Light can interact with the paper and ink in more complex ways. The Yule–Nielsen correction takes into account light entering…