Hue

	Email		Print
	Bookmark		Link

Hue

Hue is one of the main properties of a color

Color

Color or colour is the visual perception property corresponding in humans to the categories called red, yellow, blue and others....
described with names such as "red

Red

Red is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 625?740 Nanometer....
", "yellow

Yellow

Yellow is the color evoked by light that stimulates both the L and M cone cells of the retina about equally, but does not significantly stimulate the S cone cells; that is, light with much red and green but not very much blue....
", etc. The two other main properties are lightness

Lightness (color)

Lightness is a property of a color, or a dimension of a color space, that is defined in a way to reflect the subjective brightness perception of a color for humans....
and colorfulness.

Discussion

Ask a question about 'Hue'

Start a new discussion about 'Hue'

Answer questions from other users

Full Discussion Forum

Encyclopedia

Hue is one of the main properties of a color

Color

Color or colour is the visual perception property corresponding in humans to the categories called red, yellow, blue and others....
described with names such as "red

Red

Yellow

Lightness (color)

Lightness is a property of a color, or a dimension of a color space, that is defined in a way to reflect the subjective brightness perception of a color for humans....
and colorfulness. Hue is also one of the three dimensions in some colorspaces along with saturation

Saturation (color theory)

In colorimetry and color theory, colorfulness, chroma, and saturation are related but distinct concepts referring to the perceived intensity of a specific color....
, and lightness

Lightness (color)

Lightness is a property of a color, or a dimension of a color space, that is defined in a way to reflect the subjective brightness perception of a color for humans....
.

Usually, colors with the same hue are distinguished with adjectives referring to their lightness and/or chroma

Chroma

Chroma, the Greek word for color, may refer to:* The difference from gray at a given hue and lightness in the Munsell color system#Chroma* The perceived colorfulness in proportion to the brightness of a reference white patch....
, such as with "light blue", "pastel blue", "vivid blue". Exceptions include brown

Brown

Brown, when used as a general term, is a color that is a dark yellow, orange , or red, of low luminance relative to lighter or white colored objects....
, which is a dark orange

Orange (colour)

The color orange occurs between red and yellow in the visible Optical spectrum at a wavelength of about 585 ? 620 nanometre, and has a hue of 30? in HSV colour space....
, and pink

Pink

Pink is a pale red color; the use of the word for the color was first recorded in the late 17th century, describing the flowers of Dianthus, flowering plants in the genus Dianthus. Pink itself is a combination of red and white....
, a light red with reduced chroma.

In painting

Painting

Painting is the practice of applying paint, pigment, color or other medium to a surface . In art, the term describes both the act and the result, which is called a painting....
color theory

Color theory

In the visual arts, color theory is a body of practical guidance to color mixing and the visual impact of specific color combinations. Although color theory principles first appear in the writings of Leone Battista Alberti and the notebooks of Leonardo da Vinci , a tradition of "colory theory" begins in the 18th century, initially within a...
, a hue refers to a pure color—one without tint or shade

Tints and shades

In color theory, a tint is the mixture of a color with white, which increases lightness , and a shade is the mixture of a color with black, which reduces lightness....
(added white or black pigment

Pigment

A pigment is a material that changes the color of light it Reflection as the result of selective color absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which the material itself emits light....
, respectively). A hue is an element of the color wheel

Color wheel

A color wheel or color circle is an organization of color hues around a circle, showing relationships between colors considered to be primary colors, secondary colors, complementary colors, etc....
.

Computing hue

In opponent color spaces

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 cone cell and rod cell in an antagonistic manner....
in which two of the axes are perceptually orthogonal to lightness, such as CIE L*a*b* (CIELAB) and CIE L*u*v*

CIELUV color space

In colorimetry, the CIE 1976 color space, also known as the CIELUV color space, is a color space adopted by the International Commission on Illumination in 1976, as a simple-to-compute transformation of the 1931 CIE 1931 color space, but which attempted perceptual uniformity....
(CIELUV), hue may be computed together with chroma by converting these coordinates from rectangular form to polar form. Hue is the angular component of the polar representation, while chroma is the radial component.

Specifically, in CIELAB:

while, analogously, in CIELUV:

In practice, a four-quadrant arctangent may be used if available to invert these formulae.

Computing hue from RGB

Preucil describes a color hexagon, similar to a trilinear plot described by Evans, Hanson, and Brewer, which may be used to compute hue from RGB. To place red at 0°, green

Green

Green is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520?570-Nanometre....
at 120°, and blue

Blue

Blue is a colour, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 440?490 Nanometre....
at 240°, one may solve:

He also used a polar plot, which he termed a color circle. Using R, G, and B, rather than the R, G, and B densities Preucil used, one may compute hue angle using the following scheme: determine which of the six possible orderings of R, G, and B prevail, then apply the appropriate formula; see table below.

Ordering	Hue Region	Formula
	Red-Yellow
	Yellow-Green
	Green-Cyan
	Cyan-Blue
	Blue-Magenta
	Magenta-Red

Note that in each case the formula contains the fraction , where H is the highest of R, G, and B; L is the lowest, and M is the mid one between the other two. This is referred to as the Preucil Hue Error, and was used in the computation of mask strength in photomechanical color reproduction.

Hue angles computed for the Preucil circle agree with the hue angle computed for the Preucil Hexagon at integer multiples of 30 degrees (red, yellow, green, cyan, blue, magenta, and the colors mid-way between contiguous pairs), and differ by approximately 1.2 degrees at odd integer multiples of 15 degrees (based on the circle formula), the maximum divergence between the two.

The process of converting an RGB color into an HSL color space

HSL color space

HSL and HSV are two related representations of points in an RGB color space, which attempt to describe perceptual color relationships more accurately than RGB, while remaining computationally simple....
or HSV color space is usually based on a 6-piece piecewise mapping, treating the HSV cone as a hexacone, or the HSL double cone as a double hexacone. The formulae used are those in the table above.

Specialized hues

The hues exhibited by caramel colorings and beer

Beer

Beer is the world's oldest and most widely consumed alcoholic beverage and the third most popular drink overall after water and tea. It is produced by the brewing and Fermentation of starches, mainly derived from cereal?the most common of which is malted barley, although wheat, maize , and rice are widely used....
s are fairly limited in range. The Linner hue index

Linner hue index

The Linner hue index, , is used to describe the hues which a given caramel coloring may produce. In conjunction with tinctorial strength, or the depth of a caramel coloring's color, it describes the spectrum which a solution of the coloring may produce at different dilutions and thicknesses....
is used to quantify the hue of such products.

Hue as a qualification in the names of artist's colors

Manufacturers of pigments use the word hue e.g. 'Cadmium Yellow (hue)' to indicate that the original pigmentation ingredient, often toxic, has been replaced by safer (or cheaper) alternatives whilst retaining the hue of the original. Replacements are often used for chromium

Chromium

Chromium is a chemical element which has the symbol Cr and atomic number 24. It is a steely-gray, Lustre , hard metal that takes a high polish and has a high melting point....
, cadmium

Cadmium

Cadmium is a chemical element with the symbol Cd and atomic number 48. A relatively abundant , soft, bluish-white, transition metal, cadmium is known to cause cancer and occurs with zinc ores....
and alizarin

Alizarin

Alizarin is an organic compound that is historically important as a prominent dye. It is an anthraquinone originally derived from the root of the madder plant....
.

Hue vs. dominant wavelength

Dominant wavelength

In color, the dominant wavelength and complementary wavelength are ways of describing non-spectral light mixtures in terms of the Color#Spectral versus non-spectral colors light that evokes an identical perception of hue....
(or sometimes equivalent wavelength) is a physical analog to the perceptual attribute hue. On a chromaticity diagram, a line is drawn from a white point

White point

A white point is a set of tristimulus or chromaticity coordinates that serve to define the color "white" in image capture, encoding, or reproduction....
through the coordinates of the color in question, until it intersects the spectral locus

CIE 1931 color space

In the study of the perception of color, one of the first mathematically defined color spaces was the CIE 1931 XYZ color space , created by the International Commission on Illumination in 1931....
. The wavelength at which the line intersects the spectrum locus is identified as the color's dominant wavelength

Dominant wavelength

In color, the dominant wavelength and complementary wavelength are ways of describing non-spectral light mixtures in terms of the Color#Spectral versus non-spectral colors light that evokes an identical perception of hue....
if the point is on the same side of the white point as the spectral locus, and as the color's complementary wavelength if the point is on the opposite side.

Hue difference: or ?

There are two main ways in which hue difference is quantified. The first is the simple difference between the two hue angles. The symbol for this expression of hue difference is in CIELAB and in CIELUV. The other is computed as the residual total color difference after Lightness and Chroma differences have been accounted for; its symbol is in CIELAB and in CIELUV.

Hue

Computing hue

Computing hue from RGB

Specialized hues

Hue as a qualification in the names of artist's colors

Hue vs. dominant wavelength

Hue difference: or ?

See also

External links