Hunt Effect (color)
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Hunt Effect (color)
The Hunt effect or Luminance-on-colorfulness effect comprises an increase in colorfulness of a color with increasing luminance. The effect was first described by RWG Hunt in 1952. Hunt noted that this effect occurs at low luminance levels. At higher luminance, he noted a hue shift of colors to be more blue with higher luminance, which is now known as the Bezold–Brücke effect. The hunt effect is related to the Helmholtz–Kohlrausch effect, where a partially desaturated stimulus is seen to be brighter than fully saturated or achromatic stimuli. See also * Opponent process The opponent process is a color theory that states that the human visual system interprets information about color by processing signals from photoreceptor cells in an antagonistic manner. The opponent-process theory suggests that there are thr ... * Purkinje shift * Abney effect References Color appearance phenomena {{color-stub ...
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Colorfulness
Colorfulness, chroma and saturation are attributes of perceived color relating to chromatic intensity. As defined formally by the International Commission on Illumination (CIE) they respectively describe three different aspects of chromatic intensity, but the terms are often used loosely and interchangeably in contexts where these aspects are not clearly distinguished. The precise meanings of the terms vary by what other functions they are dependent on. * Colorfulness is the "attribute of a visual perception according to which the perceived color of an area appears to be more or less chromatic"., page 87. The colorfulness evoked by an object depends not only on its spectral reflectance but also on the strength of the illumination, and increases with the latter unless the brightness is very high ( Hunt effect). * Chroma is the "colorfulness of an area judged as a proportion of the brightness of a similarly illuminated area that appears white or highly transmitting". As a re ...
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Luminance
Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through, is emitted from, or is reflected from a particular area, and falls within a given solid angle. Brightness is the term for the ''subjective'' impression of the ''objective'' luminance measurement standard (see for the importance of this contrast). The SI unit for luminance is candela per square metre (cd/m2). A non-SI term for the same unit is the nit. The unit in the Centimetre–gram–second system of units (CGS) (which predated the SI system) is the stilb, which is equal to one candela per square centimetre or 10 kcd/m2. Description Luminance is often used to characterize emission or reflection from flat, diffuse surfaces. Luminance levels indicate how much luminous power could be detected by the human eye looking at a particular surface from a particular angle of view. Luminance is thus ...
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RWG Hunt
''Red. White. Green.'' is the second studio album by American metalcore band Upon a Burning Body. The album was released on April 10, 2012 through Sumerian Records. The album was produced by Will Putney, who produced their debut album, '' The World Is Ours''. All of the songs on the album are titled after films, continuing a trend set from their debut album, but this time mostly films that Robert Rodriguez produced or directed. It is the only album with Jonathan Gonzalez on drums and the last album with Chris "CJ" Johnson on guitar. Music videos were made for "Once Upon a Time in Mexico", "Sin City" and "Texas Blood Money". Also, a lyric video was made for "Mimic". The music video for "Sin City" was shot during a live performance at LKA Longhorn in Stuttgart, Germany. Track listing Credits ; Upon A Burning Body * Danny Leal - vocals * Sal Dominguez - lead guitar * Chris "C.J." Johnson - rhythm guitar * Ruben Alvarez - bass * Jonathon Gonzalez - drums ; Guest musicians * ...
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Bezold–Brücke Shift
The Bezold–Brücke shift or luminance-on-hue effect is a change in hue perception as light intensity changes. As intensity increases, spectral colors shift more towards blue (if below 500 nm) or yellow (if above 500 nm). At lower intensities, the red/green axis dominates. This means that reds become more yellow with increasing brightness. Light may change in the perceived hue as its brightness changes, despite the fact that it retains a constant spectral composition. It was discovered by Wilhelm von Bezold and M.E. Brücke. The shift in the hue of the colors that occur as the intensity of the corresponding energy change is materially increased, except in some cases like the change for certain invariable hues (approximating the psychologically primary hues). Both Bezold & Brücke worked on the Bezold-Brücke effect and gave important contributions in the field of optical illusions. This effect is a problem for simple HSV color space, HSV-style color models, which treat ...
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Helmholtz–Kohlrausch Effect
The Helmholtz–Kohlrausch effect (after Hermann von Helmholtz and V. A. Kohlrausch) is a perceptual phenomenon wherein the intense saturation of spectral hue is perceived as part of the color's luminance. This brightness increase by saturation, which grows stronger as saturation increases, might better be called chromatic luminance, since "white" or achromatic luminance is the standard of comparison. It appears in both self-luminous and surface colors, although it is most pronounced in spectral lights. Lightness Even when they have the same luminance, colored lights seem brighter to human observers than white light does. The way humans perceive the brightness of the lights is different for everyone. When the colors are more saturated, our eyes interpret it as the color's luminance and chroma. This makes us believe that the colors are actually brighter. An exception to this is when the human observer is red-green colorblind, they cannot distinguish the differences between the l ...
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Opponent Process
The opponent process is a color theory that states that the human visual system interprets information about color by processing signals from photoreceptor cells in an antagonistic manner. The opponent-process theory suggests that there are three opponent channels, each comprising an opposing color pair: red versus green, blue versus yellow, and black versus white ( luminance). The theory was first proposed in 1892 by the German physiologist Ewald Hering. Color theory Complementary colors When staring at a bright color for awhile (e.g. red), then looking away at a white field, an afterimage is perceived, such that the original color will evoke its complementary color (green, in the case of red input). When complementary colors are combined or mixed, they "cancel each other out" and become neutral (white or gray). That is, complementary colors are never perceived as a mixture; there is no "greenish red" or "yellowish blue", despite claims to the contrary. The strongest color c ...
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Purkinje Effect
The Purkinje effect (; sometimes called the Purkinje shift, often incorrectly pronounced ) is the tendency for the peak luminance sensitivity of the eye to shift toward the blue end of the color spectrum at low illumination levels as part of dark adaptation. In consequence, reds will appear darker relative to other colors as light levels decrease. The effect is named after the Czech anatomist Jan Evangelista Purkyně. While the effect is often described from the perspective of the human eye, it is well established in a number of animals under the same name to describe the general shifting of spectral sensitivity due to pooling of rod and cone output signals as a part of dark/light adaptation. This effect introduces a difference in color contrast under different levels of illumination. For instance, in bright sunlight, geranium flowers appear bright red against the dull green of their leaves, or adjacent blue flowers, but in the same scene viewed at dusk, the contrast is revers ...
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Abney Effect
The Abney effect or the purity-on-hue effect describes the perceived hue shift that occurs when white light is added to a monochromatic light source. The addition of white light will cause a desaturation of the monochromatic source, as perceived by the human observer. However, a less intuitive effect of the perceived white light addition is the change in the apparent hue. This hue shift is physiological rather than physical in nature. This variance of hue as a result of the addition of white light was first described by the English chemist and physicist Sir William de Wiveleslie Abney in 1909, although the date is commonly reported as 1910. A white light source can be created by the combination of red, blue, and green light. Abney demonstrated that the cause of the apparent change in hue was the red and green light that comprised this light source, and that the blue light component had no contribution to the Abney effect.W. de W. Abney. “On the Change in Hue of Spectrum C ...
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