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Dominant Wavelength
In color science, the dominant wavelength is a method of approximating a color's hue. Along with purity, it makes up one half of the Helmholtz coordinates. The dominant wavelength of a given color is defined to be the wavelength of monochromatic spectral light that lies on the straight line passing through the white point and the given colour in the chromaticity diagram. Determination Helmholtz coordinates The Helmholtz coordinates are a polar coordinate system for defining a 2D chromaticity plane. The circumferential coordinate is the dominant wavelength, which is analogous to hue of the HSV color space. The radial coordinate is the purity, which is analogous to saturation of the HSV color space. Color space Not all color spaces can be used for determining the dominant wavelength of a color, because in most approximately perceptually uniform color spaces (such as CIELAB, Oklab, CIECAM02, etc) two colors with the same hue can have slightly different dominant wavelengths. Unl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectral Locus
A spectral color is a color that is evoked by monochromatic light, i.e. either a spectral line with a single wavelength or frequency of light in the visible spectrum, or a relatively narrow spectral band (e.g. lasers). Every wave of visible light is perceived as a spectral color; when viewed as a continuous spectrum, these colors are seen as the familiar rainbow. Non-spectral colors (or extra-spectral colors) are evoked by a combination of spectral colors. In color spaces In color spaces which include all, or most spectral colors, they form a part of boundary of the set of all real colors. When considering a three-dimensional color space (which includes luminance), the spectral colors form a surface. When excluding luminance and considering a two-dimensional color space ( chromaticity diagram), the spectral colors form a curve known as the spectral locus. For example, the spectral locus of the CIE xy chromaticity diagram contains all the spectral colors (to the eye of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Naming
A color term (or color name) is a word or phrase that refers to a specific color. The color term may refer to human perception of that color (which is affected by visual context) which is usually defined according to the Munsell color system, or to an underlying physical property (such as a specific wavelength on the spectrum of visible light). There are also numerical systems of color specification, referred to as color spaces. An important distinction must be established between color and shape, as these two attributes usually are used in conjunction with one another when describing in language. For example, they are labeled as alternative parts of speech terms color term and shape term. Psychological conditions for recognition of colors exist, such as those who cannot discern colors in general or those who see colors as sound (a variety of synesthesia). Color dimensions Typical human color vision is trichromatic, meaning it is based on a three-dimensional color gamut. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photometry (optics)
Photometry is a branch of optics that deals with measuring light Light, visible light, or visible radiation is electromagnetic radiation that can be visual perception, perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400– ... in terms of its perceived brightness to the human eye. It is concerned with quantifying the amount of light that is emitted, transmitted, or received by an object or a system. In modern photometry, the radiant power at each wavelength is weighted by a luminosity function that models human brightness sensitivity. Typically, this weighting function is the photopic vision, photopic sensitivity function, although the scotopic vision, scotopic function or other functions may also be applied in the same way. The weightings are standardized by the International Commission on Illumination, CIE and International Organization for Standardization, ISO. Photometry is distinct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiant Flux
In radiometry, radiant flux or radiant power is the radiant energy emitted, reflected, transmitted, or received per unit time, and spectral flux or spectral power is the radiant flux per unit frequency or wavelength, depending on whether the spectrum is taken as a function of frequency or of wavelength. The SI unit of radiant flux is the watt (W), one joule per second (), while that of spectral flux in frequency is the watt per hertz () and that of spectral flux in wavelength is the watt per metre ()—commonly the watt per nanometre (). Mathematical definitions Radiant flux Radiant flux, denoted ('e' for "energetic", to avoid confusion with photometric quantities), is defined as \begin \Phi_\mathrm &= \frac \\ ptQ_\mathrm &= \int_ \int_ \mathbf\cdot \hat\mathbf\, dA dt \end where * is the time; * is the radiant energy passing out of a closed surface ; * is the Poynting vector, representing the current density of radiant energy; * is the normal vector of a point on ; * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiometry
Radiometry is a set of techniques for measurement, measuring electromagnetic radiation, including visible light. Radiometric techniques in optics characterize the distribution of the radiation's power (physics), power in space, as opposed to photometry (optics), photometric techniques, which characterize the light's interaction with the human eye. The fundamental difference between radiometry and photometry is that radiometry gives the entire optical radiation spectrum, while photometry is limited to the visible spectrum. Radiometry is distinct from quantum optics, quantum techniques such as photon counting. The use of radiometers to determine the temperature of objects and gasses by measuring radiation flux is called pyrometry. Handheld pyrometer devices are often marketed as infrared thermometers. Radiometry is important in astronomy, especially radio astronomy, and plays a significant role in Earth remote sensing. The measurement techniques categorized as ''radiometry'' in op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planckian Locus
In physics and color science, the Planckian locus or black body locus is the path or locus (mathematics), ''locus'' that the color of an black-body radiation, incandescent black body would take in a particular chromaticity space as the blackbody temperature changes. It goes from deep red at low temperatures through orange (color), orange, yellowish, white, and finally blue, bluish white at very high temperatures. A color space is a three-dimensional space; that is, a color is specified by a set of three numbers (the CIE 1931 color space, CIE coordinates ''X'', ''Y'', and ''Z'', for example, or other values such as hue, colorfulness, and luminance) which specify the perceived attributes of a particular homogeneous visual stimulus. A chromaticity is a color projected into a Plane (mathematics), two-dimensional space that ignores brightness. For example, the standard CIE XYZ color space projects directly to the corresponding chromaticity space specified by the two chromaticity coord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complementary Color
Complementary colors are pairs of colors which, when combined or color mixing, mixed, cancel each other out (lose Colorfulness, chroma) by producing a grayscale color like white or black. When placed next to each other, they create the strongest contrast (vision), contrast for those two colors. Complementary colors may also be called "opposite colors". Which pairs of colors are considered complementary depends on the color model that one uses: * Modern color theory uses either the RGB color model, RGB additive color model or the CMYK color model, CMY subtractive color model, and in these, the complementary pairs are red–cyan, green–magenta (one of the purples), and blue–yellow. * In the traditional RYB color model, the complementary color pairs are red–green, yellow–purple, and blue–orange (colour), orange. * Opponent process theory suggests that the most contrasting color pairs are red–green and blue–yellow. * The black–white color pair is common to all the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monochromatic Radiation
{{More citations needed, date=May 2023 In physics, monochromatic radiation is electromagnetic radiation with a single constant frequency or wavelength. When that frequency is part of the visible spectrum (or near it) the term monochromatic light is often used. Monochromatic light is perceived by the human eye as a spectral color. When monochromatic radiation propagates through vacuum or a homogeneous transparent medium, it remains with a single constant frequency or wavelength; otherwise, it suffers refraction. Practical monochromaticity No radiation can be totally monochromatic, since that would require a wave of infinite duration as a consequence of the Fourier transform's localization property (cf. spectral coherence). In practice, "monochromatic" radiation — even from lasers or spectral lines — always consists of components with a range of frequencies of non-zero width. Generation Monochromatic radiation can be produced by a number of methods. Isaac Newton observe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kelvin
The kelvin (symbol: K) is the base unit for temperature in the International System of Units (SI). The Kelvin scale is an absolute temperature scale that starts at the lowest possible temperature (absolute zero), taken to be 0 K. By definition, the Celsius scale (symbol °C) and the Kelvin scale have the exact same magnitude; that is, a rise of 1 K is equal to a rise of 1 °C and vice versa, and any temperature in degrees Celsius can be converted to kelvin by adding 273.15. The 19th century British scientist Lord Kelvin first developed and proposed the scale. It was often called the "absolute Celsius" scale in the early 20th century. The kelvin was formally added to the International System of Units in 1954, defining 273.16 K to be the triple point of water. The Celsius, Fahrenheit, and Rankine scales were redefined in terms of the Kelvin scale using this definition. The 2019 revision of the SI now defines the kelvin in terms of energy by setting the Bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Illuminant D65
A standard illuminant is a theoretical source of visible light with a spectral power distribution that 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 (1967) represent variations of daylight, illuminant E is the equal-energy illuminant, while illuminants F (2004) 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Temperature
Color temperature is a parameter describing the color of a visible light source by comparing it to the color of light emitted by an idealized opaque, non-reflective body. The temperature of the ideal emitter that matches the color most closely is defined as the color temperature of the original visible light source. The color temperature scale describes only the ''color'' of light emitted by a light source, which may actually be at a different (and often much lower) temperature. Color temperature has applications in lighting, photography, videography, publishing, manufacturing, astrophysics, and other fields. In practice, color temperature is most meaningful for light sources that correspond somewhat closely to the color of some black body, i.e., light in a range going from red to orange to yellow to white to bluish white. Although the concept of correlated color temperature extends the definition to any visible light, the color temperature of a green or a purple light rar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
