		COLOR PHENOMENA				Page: 01. 02
Introduction	Ingredients	Spectra	Attributes	The Human Eye	Color Mixing	General Terms
Color Spaces	How to measure	Color Scales	Color Effects	After Images		Contents

	*Introduction*
INDEX.html on page 01.00 CONTENTS and LAYOUT on page 01. 01 COLOR-GLOSSARY on this page

G L O S S A R Y

CONSTANT UNDER CONSTRUCTION

A
A...	CIE Standard Illuminant for incandescent illumination, YELLOW-ORANGE in color, with a correlated Color Temperature of 2854 KELVIN.
a and a*	RED-GREEN coordinate in certain transformed color spaces ( Hunter Lab and CIELAB ), generally used as the difference in "a" between a specimen and a standard reference color. If "a" is positive, there is more RED than GREEN. If "a" is negative, there is more GREEN than RED. It is normally used with b and b* as part of the chromaticity or chromaticity color difference.
Achromatic	1	A neutral color such as BLACK, WHITE or GREY.
Achromatic	2	A color without HUE. See Chromatic
Additive Primary Colors		RED light, GREEN light and BLUE light are the additive primaries colors. [ RGB ] See also Subtractive Primary Colors
Additive Color Mixing	1	Superposition or other nondestructive combination of light of different chromaticity's, the visual effects of which depend only on their chromaticity's and not on their spectral distributions.
	2	Mixing colors by stimulating the eye with two or more sets of wavelengths simultaneously.
	3	When light colors are combined, the result becomes successively lighter.
	4	A mixture in which the light from each of the components reaches the eye in an unmodified state. Lights superimposed on a projection screen are an example of an additive mixture. See also Subtractive Color mixing
Angle of Incidence	1	The angle between the axis of an impinging light beam and perpendicular to the specimen surface.
	2	The angle between an incident ray of light and the normal to the surface at the point of incidence.
	3	When light strikes a surface it forms an angle with an imaginary line known as the "normal" which is perpendicular to the surface.
Anomia	See <Color Anomia>
Appearance	Manifestation of the nature of objects and materials through visual attributes such as size, shape, color, texture, glossiness, transparency, opacity, etcetera.
Attribute	1	Distinguishing characteristic of a sensation, perception or mode of appearance; distinction is made between chromatic and geometric appearance attributes.
Attribute	2	Colors are often described by their attributes of hue, saturation and lightness.
Artificial Illuminants	1	A synthetic light source of spectral distribution as close as possible to that of the natural illuminant (usually daylight) to be duplicated.
	2	All light not originating from a natural source (normally the sun).
	3	A man-made light source.

B
B..	An illuminant that presents a Color Temperature of 4874 Kelvin.
b and b*	Yellow-Blue coordinate in certain transformed color spaces ( Hunter Lab and CIELAB ), generally used as the difference in "b" between a specimen and a standard reference color. If "b" is positive, there is more YELLOW than BLUE. If "b" is negative, there is more BLUE than YELLOW. It is normally used with a and a* as part of the chromaticity or chromaticity color difference.
Binary hue	Binary hue as orange appears to be a mixture of red and yellow. All binary hues are mixtures of two of the Unique Hues.
Black	1	The absence of all reflected light.
	2	BLACK is the color that is produced when an object absorbs all wavelengths from the light source.
	3	The letter "K" is used to represent BLACK in the CMYK acronym to avoid confusion with BLUE [ B ] in [ RGB ].
Blackbody	A thermal radiator of uniform temperature whose radiant existence in all parts of the spectrum is maximum obtained from any thermal radiator at the same temperature. A blackbody radiator as a body which absorbs all radiation falling on it and reflects none.
Brightness to explain later on page 05.02	1	The attribute of visual sensation by which an observer aware of differences in luminance or lightness .
	2	Brightness Constancy: The perceptual process that makes an object maintain a particular level of brightness despite changes in the amount of light reflected from it.
	3	Brightness Constancy: The tendency to perceive an object as being just as bright even though lighting conditions change the intensity with which it impacts on the eye.
	4	Brightness Constancy: The ability of the brain to ignore differences in luminance under certain conditions in order to make sensed of the visual environment.
	5	Brightness is equivalent to Lightness and equivalent to Luminance and equivalent to Value.
	6	The attribute of visual perception in accordance with which an area appears to emit or reflect more or less light ( this attribute of color is used in the color model [ HSB ] - Hue, Saturation, BRIGHTNESS ). See also Lightness and LUMINANCE and VALUE.

C
C.	The CIE Standard illuminant that presents a Color Temperature of 6774 KELVIN.
Cartesian Coordinates	A system of coordinates for location a point on a plane by its distance from each of two perpendicular intersecting lines, or in space by the distance from each of three mutually perpendicular planes intersecting at a point.
Chroma	1	Chroma as the attribute of visual perception in accordance with which an area appears saturated with a particular color hue. A red apple is high in chroma, pastel colors are low in chroma and black, gray and white have no chroma.
	2	This attribute of color is used in the color model [ LCH* ] L* for LIGHTNESS C* for CHROMA H* for HUE
	3	The attribute CHROMA also referred to SATURATION and also to PURITY.
Chromatic	Chromatic Color or Hue. All colors other than the neutral colors as black, white and real gray are chromatic.
Chromaticity	Location in a Chromaticity Diagram.. Chromaticity is often used as a convenient approximation to chromaticness, which is the Hue and Saturation of a color ignoring Brightness.
Chromaticity Coordinates	1	Dimensions of a color stimulus expressed in terms of Hue and Saturation, or redness-greenness and yellowness-blueness, excluding the luminous intensity.
Chromaticity Coordinates	2	Coordinates that specify position in a Chromaticity Diagram. The chromaticity coordinates of a stimulus are derived from its tristimulus values by taking the ratio of each of the tristimulus values to their sum. As x=X/X+Y+Z , y=Y/X+Y+Z and z=Z/X+Y+Z where x and y are the chromaticity coordinates and X , Y and Z the tristimulus values.
Chromaticity Diagram	A diagram that represents the unit plane in a tristimulus space. The plane defined as the equation: X+Y+Z=1
CIE	CIE: The Commission Internationale de l' Eclairage (in Paris France) is the International Commission on Illumination, that recommends standards and procedures for light and lightning, including colorimetry.
CIE Illuminant C	A standard illuminant that is an approximation to average daylight. All illuminants are specified by their spectral power distribution.
CIE 1931 2^o Standard Observer	CIE 1931 2^o Standard Observer is the ideal colorimetric observer with color matching functions x^-₂(y), y^-₂(y), z^-₂(y) corresponding to a field of view subtending a 2^o angle on the retina; commonly called: The 2^o Standard Observer.
CIE 1964 10^o Standard Observer	CIE 1964 Supplementary Standard Observer is the ideal colorimetric observer with color matching functions x^-₁₀(y), y^-₁₀(y), z^-₁₀(y) corresponding to a field of view subtending a 10^oangle on the retina; commonly called: The 10^o Standard Observer.
CIE Standard Illuminants	Known spectral data established by the CIE for four different types of light sources. When using tristimulus data to describe a color, the illuminant must also be defined. These standard illuminants are used in place of actual measurements of the light source.
CIELAB	1	CIELAB as a color space in which values L, a and b* are plotted at right angles to one another to form a three dimensional system.
	2	CIELAB or CIE Lab*
	3	CIELAB or CIE Lab
CMC	Color Measurement Committee Of the Society of Dyes and Colorists in Great Britain. Developed a more logical, ellipse-based equation for computing (E values as an alternative to the rectangular coordinates of the CIELAB color space.)
CMY	The subtractive primary colors CYAN, MAGENTA, and YELLOW. See also Additive Primary Colors
Color Anomia	An inability to name colors despite intact color vision as demonstrated by non-verbal tests.
Color Constancy	1	The phenomenon whereby a viewer perceives the hue, saturation and lightness of a stimulus as remaining unchanged when the color quality and the level of the illumination are changed.
	2	The psychology tendency to see colors as we think they are rather than as we actually perceive them.
	3	The ability of the brain to ignore differences in coloration due to differences in illumination.
	4	Tendency to see the hue of an object as staying the same despite changes in the color of the light falling on it.
	5	The tendency to see a familiar object as of the same color, regardless of changes in illumination on it that alter its stimulus properties.
	6	The relative independence of perceived object colors to change in color of the light source or in viewing conditions.
	7	Stability in the perceived color of a surface across changes in illumination and the consequent changes in the light reaching the eye.
Color Space	A system for ordering colors that respects the relationship of similarity among them. There are a variety of different color spaces, but they are mostly three dimensional.
Color Temperature	1	The temperature of a perfect Blackbody radiator whose chromaticity is closest to that of the light under consideration.
	2	A measurement of the color of light radiated by an object while it is being heated. This measurement is expressed in terms of absolute scale, or degrees Kelvin. Lower Kelvin temperatures such as 2400 K are red; higher temperatures such as 9300 K are blue. Neutral temperature is gray, at 6504 K.
	3	The temperature of the Planckian radiator whose radiation has the same chromaticity as that of a given stimulus.
Complementary Colors	1	Colors opposite each other on a color wheel, as red and green, yellow and violet, blue and orange. Complementary colors often make good accent colors.
	2	Two colors of light that combine to make white light in the additive color mixing system. For red, green and blue, the complementary colors are cyan, magenta and yellow.
	3	Pairs of colors that have the maximum contrast and so, when set side by side, intensify one another.
	4	Any two colors of light that when combined include all the wavelength of light and thus produce white light. Any two dye colors that when combined absorb all wavelengths of light and thus produce black. A colored filter absorbs light of its complementary color and passes the light of its own color.
	5	When two ore more colors "go together", they are said to be complementary. This is completely subjective and open to interpretation and differences in opinion. A more exact definition is: any two colors that, when mixed together produce a neutral gray by using pigments or white by using light.
	6	Any two colors on a color wheel which are opposite to each other are called complements or opposites. Examples are red and green, blue and orange, yellow and purple. Note that one color is a primary, while the other is a mix of the other two primaries. Other complement pairs are tertiary colors. blue/green and red/orange for example. When a small amount of a color's complement is mixed with it, like adding a touch of orange to blue, the effect is to gray down that color, making it more subtle. It's possible to use very bright hues to gain very subtle colors when this is understood.
Colorants	Materials used to create colors, dyes, pigments, toners, phosphors.
Cone	A photoreceptor found in the human eye. There are three types of cones. The three types of cones have maximum sensitivities in the blue, green, and red regions of the spectrum, with absorption peaks near 445 nm, 535 nm, and 565 nm, respectively. These three sets are often designated as S, M, and L for their sensitivity to short, medium, and long wavelengths.
Correlated Color Temperature (CCT)	A term used to describe the color of a light source whose chromaticity lies close to the Planckian (black body) locus on a CIE Chromaticity chart. Specifically, it is the temperature of a black body radiator which produces the chromaticity most similar to that of the light source evaluated. It is usually expressed in Kelvin.
Cyan	One of the process ink colors for printing. Pure cyan is the "red less" color; it absorbs all red wavelengths of light and reflects all BLUE and GREEN wavelengths. TURQUOISE is also a BLUE-GREEN color

D
D-50	An illuminant that presents a Color Temperature of 5000 KELVIN.
D-65	The CIE Standard illuminant that presents a Color Temperature of 6500 KELVIN.
Deep Color	Deep Color is a term used to describe a method of representing graphical image data using an extremely large number of shades, hues and luminosities, capable of displaying millions of possible colors. It is often employed when display media have a very wide color gamut. Deep Color is sometimes referred to as the successor to t rue color.
Deuteranopia	1	A defect of the vision in which the retina fails to respond to GREEN.
	2	Colorblindness of the RED-GREEN type, also known as deuteranomaly or Daltonism.
	3	Dichromacy characterized by a lowered sensitivity to GREEN light resulting in an inability to distinguish GREEN and purplish-RED.
	4	Color blindness in which RED and GREEN are confused. Also called RED-GREEN color blindness.
	5	People with deuteranopia the M cones are missing perceive only BLUE and YELLOW.
Delta	A symbol used to indicate deviation or difference.
Dichromatism	A defect of vision in which the retina responds to only two of the three primary colors.
Dominant wavelength	1	Any color, when plotted on the CIE diagram may be specified in terms of its' dominant wavelength, which is the wavelength of the spectrum locus where the line drawn from the chromaticity point of the illuminant, through the chromaticity point of the color and then extended, intersects the locus. Dominant wavelength is generally abbreviated to λd
	2	The dominant wavelength of a color in the purple triangle of the chromaticity diagram bounded by the illuminant point, 400nm and 700nm on the spectrum locus is specified as the complementary of the greenish color found on the spectrum locus by extending the line joining the illuminant point to the sample color backwards to the top of the CIE diagram. it is abbreviated to λc.
	3	The dominant wavelength of the emerald-green pigment is 511.9 nm

E
E.	An illuminant that presents a Color Temperature of 5000 KELVIN
Electromagnetic Spectrum	The massive band of electromagnetic waves that pass through the air in different sizes, as measured by wavelength. Different wavelengths have different properties, but most are invisible, and some completely undetectable, to human beings. Only wavelengths between 400 and 700 nanometers are visible. Invisible waves outside the visible spectrum include gamma rays, x-rays, microwaves and radio waves.
Electron Volt	The amount of energy required to move an electron across a potential difference of one volt. A common unit of energy in physics. Energy in "eV"

F
Farnsworth-Munsell test	A test for deficiencies of color vision in which the subject is asked to arrange a set of 100 colored chips in a circle. Subjects with normal color vision will arrange the chips in a specific order with very few deviations. Subjects with abnormal color vision will deviate from the normal arrangement in ways that provide information about the nature of their defect.
Fluorescence	The absorption of light at one wavelength and its re-emission at a longer wavelength. Fluorescence plays an important role in the perceived color f many objects: the unnatural brightness of "day-glo" paints is due to fluorescence.
Four Color Process	Depositing combinations of the subtractive primaries CYAN, MAGENTA, YELLOW and BLACK on paper to achieve. These colorants are deposited as dots of different sizes, shapes, and angles to create the illusion of different colors. See also CMY and Subtractive Primary Colors .

G
Gamut	The range of different colors that can be interpreted by a color model or generated by a specific device.
Gamut Compression	Or total range compression. The color space coordinates of a color space with a larger gamut are reduced to accommodate the smaller gamut of a destination color space. For example, the gamut of photographic film is compressed for representation in the smaller CMYK gamut used for four color processing printing. See also Gamut
Gamut Mapping	Converting the coordinates of two or more color spaces into a common color space. Often results in tonal range compression. See also Gamut Compression

H
Helson-Judd-Effect	The tendency of lighter achromatic surfaces to take on the hue of the illuminant under which they are viewed and darker achromatic surfaces to take on the complementary hue.
Hue	1	The property of light by which the color of an object is classified as red, blue, green or yellow in reference to the spectrum.
	2	A gradation or variety of a color.
	3	An other name for color. Hue differences depend primarily on variation in the wavelengths of light reaching the human eye.

I
Illuminant A (CIE)	The CIE Standard Illuminant A that presents a Color Temperature of 2854 KELVIN
Intensity	The power of a light, often weighted by the spectral sensitivity of the human eye.
Ishihara Test	A test for colorblindness using a set of pseudoisochromatic plates

J

K
Kelvin	Unit of measurement for Color Temperature. The Kelvin scale starts from absolute zero, which is -273� Celsius.

L
Lambertian Surface	A perfectly diffusing surface; the intensity of the light emanating in a given direction from any small surface component is proportional to the cosine of the angle of the normal to the surface. The Brightness (Luminance, Radiance) of a Lambertian Surface is constant regardless of the angle from which it is viewed.
L-cone	One of three cone types that contribute to human color vision. The L-cones have their peak spectral sensitivity at a longer wavelength than the other two cone types, the M-cones and S-cones.
Light	Electromagnetic radiation in the spectral range detectable by the human eye.
Lightness	1	Lightness is equivalent to Brightness and equivalent to Luminance and equivalent to Value.
	2	The attribute of visual perception in accordance with which an area appears to emit or reflect more or less light. Also refers to the perception by which white objects are distinguished from gray objects and light- from dark-colored objects.
Light Source A (CIE)	The CIE Standard Illuminant A that presents a Color Temperature of 2854 Kelvin
Lumen	lm The unit of luminous flux. The lumen is the luminous flux emitted within 1 steradian by a point source having a luminous intensity of 1 candela.
Luminance	1	Luminance is equivalent to BRIGHTNESS and equivalent to LIGHTNESS and equivalent to VALUE.
	2	Luminous intensity per unit projected area of any surface, as measured from a specific direction.
	3	The physical measure of BRIGHTNESS.
	4	Standard unit of LUMINANCE is cd/m² (candela per square meter)

M
Magenta	One of the process ink colors for printing. Pure magenta is the �greenless� color; it absorbs all wavelengths of green from light and reflects all red and blue wavelengths.
M-cone	One of the three cone types that contribute to human color vision. The peak spectral sensitivity of the M-cones is between the peak sensitivity of the other two cone types, the L-cones and S-cones.
Metameric match	A color match between physically different stimuli. A match between stimuli with different reflectance's or spectral power distributions. Such stimuli that match (for an observer and a viewing condition) are metamers (with respect to that observer and that viewing condition).
Metamerism	A layman can recognize metamerism when two colored objects that match under one illuminant fail to match under an other illuminant
Monochromatism	A defect of vision in which the retina fails to perceive color. Persons who have no functioning cone system suffer from the extremely rare monochromatism and can perceive only grays.
Munsell color system	A widely used system for describing the color appearance of samples. The Munsell system uses matching against a set of samples and interpolation between them to arrive at a designator for the appearance of a given test sample. Color appearance in the Munsell system is characterized using sets of three symbols, for example 2.5 YR 5/10. 2.5 YR is the HUE, 5/ the VALUE (= LIGHTNESS), and /10 the CHROMA

N
Nanometer	One billionth of a meter. 10^-9 meter^.The most common unit used for characterizing the wavelength of light in visual science.

O
Overprint	On a press sheet color bar, overprints are color patches where two process inks have been printed, one atop the other. Checking the density of these patches allows press operators to determine trap value. The term Overprint also applies to any object printed on top of other colors.

P
Pigment	An insoluble colorant; as opposed to a dye, which is soluble.
Primary Colors	The dominant regions of the visible spectrum: red, green, and blue.
Prism	Triangular-shaped glass or other transparent material. When light is passed through a prism, its wavelengths refract into a rainbow of colors. This demonstrates that light is composed of color, and indicates the arrangement of colors in the visible spectrum.
Protanopia	A defect of the vision in which the retina fails to respond to red. People with protanopia the L cones are missing and perceive only blue and yellow.
Pseudoiso Chromatic Plates	Common test for color blindness that use patterns of colored dots.

R
Reflectance	The percentage of light that is reflected from an object. Spectrophotometers measure an object�s reflectance at various intervals along the visible spectrum to determine the object color�s spectral curve
Reflective Object	A solid object that returns some or all of the wavelengths of light that strike its surface. A reflective object that returns 100% of all light is called a perfect diffuser � a perfectly white surface.
RGB	The additive primary colors Red, Green and Blue. See also Subtractive Primary Colors

S
Saturation	1	The colorfulness of an area judged in proportion to its brightness.
Saturation	2	The attribute of color perception that expresses the amount of departure from the neutral gray of the same lightness. Also referred to as CHROMA.
S-cone	One of the three cone types that contribute to human color vision. The peak spectral sensitivity of the S-cones is at a shorter wavelength than that of the other two cone types, the L-cones and M-cones.
Simultaneous Contrast	1	A property of complementary colors when placed side by side, resulting in the fact that both appear BRIGHTER and more intense than when seen in isolation.
	2	An optical effect caused by the tendency of contrasting forms and colors to emphasize their difference when they are placed together.
	3	The color of interest is influenced by its surroundings. A neutral object will appear to have a hint of the background complementary color.
	4	The effect produced by the fact that any region in the visual field tends to induce its complementary color in adjoining areas. A GRAY patch will tend to look BLUISH if surrounded by yellow and look YELLOWISH if surrounded by BLUE.
	5	The phenomenon in which the perceived color of an area of a scene tends to take on a HUE opposite to that of the surrounding area. Thus a GRAY square on a red background will take on a GREENISH tint.
	6	An optical effect caused by the tendency of contrasting forms and colors to emphasize their difference when they are placed together.
	7	The tendency for colors at the opposite ends of the primary scale to perceptually "jump" when placed together; for example, red and green.
	8	The phenomenon in which the perceived color of an area of a scene tends to take on a hue opposite to that of the surrounding area. Thus a grey square on a red background will take on a greenish tint.
	9	When two different color tones come into direct contact, the contrast intensifies the difference between them.
Spectrophotometry	Measurements of the relative amounts of radiant flux at each wavelength of the spectrum.
Spectrum	Spatial arrangement of electromagnetic energy in order of wavelength size. See Electromagnetic Spectrum, Visible Spectrum.
Standard	An established, approved reference against which instrument measurements of samples are evaluated.
Subtractive Color Mixing	1	A color mixture in which the light from each component is modified by the others. Since pigments modify light by absorbing a portion of the incident light and thus each pigment will modify the light from the others, pigment mixtures are subtractive mixtures. See also Additive Color Mixing
Subtractive Color Mixing	2	When all three subtractive primaries are combined on white paper, black is produced.
Subtractive Primary Colors	Cyan, Magenta, and Yellow are the subtractive primaries colors. [ CMY ]. See also Additive Primary Colors
Successive Contrast	The influence of the color of an area on the perceived color of an area viewed immediately afterward. See also After Images.

T
Tolerance	The amount of acceptable difference between a known correct standard (usually the customer�s specifications) and a set of measured samples.
Transmissive Object	An object that allows light to pass through from one side to the other. The color of a transmissive object results from the manipulation of wavelengths of light as they pass through.
Trichromatism	A normal vision in which the retina responds to all colors.
Tristimulus	1	The tristimulus values that combine to define or generate a specific color, such as [ R255-G255-B000 ]. Tristimulus values does not completely describe a color, the illuminant must also be defined.
	2	A method for communicating or generating a color using three stimuli; either additive or subtractive colorants such as [ RGB ] or [ CMY ] or three attributes as LIGHTNESS, CHROMA and HUE.
Tritanopia
	1	A defect of the vision in which the retina fails to respond to blue and yellow.
	2	People with tritanopia the S cones are missing and only green and red are perceived.

U
Unique Hue	Unique Hue as an unmixed chromatic component. The four Unique Hues RED, GREEN, YELLOW and BLUE are thought to be basic components out of which all other Binary Hues are composed.

V
Value	Value is equivalent to Brightness and equivalent to Luminance and equivalent to Lightness .
Visible Spectrum
	1	The region of the electromagnetic spectrum between 400 and 700 nanometers. Wavelengths inside this span create the sensation of color when they are viewed by the human eyes.
	2	Band of electromagnetic radiation ranging from wavelengths of approximately 400 to approximately 700 nanometers, corresponding to the sensitivity of the human eye. Sensitivity does not drop to zero at the standard endpoints of the visible spectrum, but is so low that light outside these limits rarely has a significant effect on visual response. Many non-human animals respond significantly to light outside this range, especially to light of shorter wavelengths.

W
Wave	A physical activity that rises and then falls periodically as it travels through a medium.
Wavelength	Light is made up of electromagnetic waves; wavelength is the crest (peak)-to-crest distance between two adjacent waves.
Weber's Law	1	The thesis that perceptual systems respond in such a way so as to make the ratio between the minimum perceptible change in a physical magnitude and the absolute value of that magnitude a constant.
	2	Weber's Law predict that the smallest detectable intensity difference between two lights will be larger on a bright background than a dim one. This conclusion is approximately true for high light levels.
White Light	In theoretically, LIGHT that emits all wavelengths of the visible spectrum at uniform intensity. In reality, most LIGHT sources cannot achieve such perfection.
Whiteness	An attribute of color perception by which an object color is judged to approach the preferred white

X
X	X is one of the three CIE-Tristimulus values. Primary RED

Y
Y	Y is one of the three CIE-Tristimulus values. Primary GREEN
Yellow	Yellow is one of the process ink colors for printing. Pure yellow is a blue less color, it absorbs all wavelengths of blue from light and reflects all red and green wavelengths.

Z
Z	Z is one of the three CIE-Tristimulus values. Primary BLUE

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Last update
2009-03-23