Natural Color System
Encyclopedia
Property
Property is any physical or intangible entity that is owned by a person or jointly by a group of people or a legal entity like a corporation...
perceptual
Perception
Perception is the process of attaining awareness or understanding of the environment by organizing and interpreting sensory information. All perception involves signals in the nervous system, which in turn result from physical stimulation of the sense organs...
color model published by the Scandinavian Colour Institute (Skandinaviska Färginstitutet AB) of Stockholm, Sweden. It is based on the color opponency
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...
description of color vision, first proposed by German physiologist Ewald Hering
Ewald Hering
Karl Ewald Konstantin Hering was a German physiologist who did much research into color vision and spatial perception...
. The system is usually used for matching colors (using printed reference cards), rather than mixing colors.
The underlying physiological mechanisms involved in color opponency include the bipolar
Bipolar cell
As a part of the retina, the bipolar cell exists between photoreceptors and ganglion cells. They act, directly or indirectly, to transmit signals from the photoreceptors to the ganglion cells.-Overview:...
and ganglion cell
Ganglion cell
A retinal ganglion cell is a type of neuron located near the inner surface of the retina of the eye. It receives visual information from photoreceptors via two intermediate neuron types: bipolar cells and amacrine cells...
s in the retina
Retina
The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical...
, which process the signal originated by the retinal cones before it is sent to the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
. A model like RGB describes what happens at the lower, retinal cone level, and thus is very well fitted for the task of "fooling the eye" as done by TV sets and computer display
Computer display
A monitor or display is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure...
s. The NCS model, for its part, describes the organization of the color sensations as perceived at the upper, brain level, and thus is much better fitted than RGB to deal with how humans experience and describe their color sensations (hence the "natural" part of its name); but it would be useless, for example, for describing the behavior of mixing lights and pigments.
The NCS is based on the six elementary color
Color
Color or colour is the visual perceptual property corresponding in humans to the categories called red, green, blue and others. Color derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors...
percepts of human vision—the psychological primaries—as described by color opponency—white
White
White is a color, the perception of which is evoked by light that stimulates all three types of color sensitive cone cells in the human eye in nearly equal amounts and with high brightness compared to the surroundings. A white visual stimulation will be void of hue and grayness.White light can be...
, black
Black
Black is the color of objects that do not emit or reflect light in any part of the visible spectrum; they absorb all such frequencies of light...
, 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 630–740 nm. Longer wavelengths than this are called infrared , and cannot be seen by the naked eye...
, yellow
Yellow
Yellow is the color evoked by light that stimulates both the L and M cone cells of the retina about equally, with no significant stimulation of the S cone cells. Light with a wavelength of 570–590 nm is yellow, as is light with a suitable mixture of red and green...
, 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 nanometres. In the subtractive color system, it is not a primary color, but is created out of a mixture of yellow and blue, or yellow and cyan; it is considered...
, 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 nm. It is considered one of the additive primary colours. On the HSV Colour Wheel, the complement of blue is yellow; that is, a colour corresponding to an equal...
—which are difficult to define perceptually in terms of others (for example, one cannot describe color red as looking "like a yellow and magenta mixture", even though you will in fact get a red pigment by mixing yellow and magenta pigments). These six elementary colors are frequently chosen to paint educational toys, or for designs that try to appeal from their simplicity (such as the Olympic flag and the Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
logo). All the other perceptual colors are composite perceptions that can be defined in terms of those six (for example, turquoise looks like "bluegreen", orange like "a color that is both reddish and yellowish", and brown looks like "a very dark orange", that is, like a mixture of red, yellow and black). This all means the appearance of a color can be readily predicted from its NCS notation, whereas its notation in systems such as RGB often looks unintuitive (for example, yellow does not look like "a reddish-greenish color" at all, even though the yellow on an RGB monitor is obtained by mixing red and green lights). Note also that, under normal viewing circumstances, there is no hue that must be described as a mixture of opponent hues; that is, as a hue looking "redgreen" or "yellowblue" (see note in the color opponents
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...
article).
Colors in the NCS are defined by three values, specifying the amount of blackness (darkness), chromaticity
Chromaticity
Chromaticity is an objective specification of the quality of a color regardless of its luminance, that is, as determined by its hue and colorfulness ....
(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. Colorfulness is the degree of difference between a color and gray. Chroma is the colorfulness relative to the brightness of another color...
), and a percentage
Percentage
In mathematics, a percentage is a way of expressing a number as a fraction of 100 . It is often denoted using the percent sign, “%”, or the abbreviation “pct”. For example, 45% is equal to 45/100, or 0.45.Percentages are used to express how large/small one quantity is, relative to another quantity...
value between two of the colors red, yellow, green or blue (hue
Hue
Hue is one of the main properties of a color, defined technically , as "the degree to which a stimulus can be describedas similar to or different from stimuli that are described as red, green, blue, and yellow,"...
). The blackness and the chromaticity together add up to less than or equal to 100%—their remainder from 100%, if any, gives the amount of whiteness. The complete NCS color notations can also be tagged with a letter giving the version of the NCS color standard that was used to specify the color.
Two examples of NCS color notation—the yellow and blue shades of the Swedish flag:
- Yellow – NCS 0580-Y10R (= 5% darkness, 80% saturation, 90% yellow + 10% red = very slightly darkish mostly saturated yellow with a slight orangish tinge)
- Blue – NCS 4055-R95B (= 40% darkness, 55% saturation, 5% red + 95% blue = somewhat dark rather unsaturated blue with a very slight purplish tinge)
The NCS is represented in 19 countries and is the reference norm for color designation in Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
(since 1979), Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
(since 1984) and Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
(since 1994). It is also one of the standards used by the International Colour Authority
International Colour Authority
The International Colour Authority is a private organization publishing forecasts about colour trends for the coming seasons, to be used by industry designers. It also awards a Seal of Approval that companies may display in their promotional materials if the colour ranges they use are appraised by...
, a leading publisher of color trend forecasts for the interior design
Interior design
Interior design describes a group of various yet related projects that involve turning an interior space into an effective setting for the range of human activities are to take place there. An interior designer is someone who conducts such projects...
and textile markets.
Overview of the six base colors in Natural Color System with their equivalent in hex triplet, RGB and HSV coordinates systems.
| Color | Hex triplet | RGB | HSV |
|---|---|---|---|
| White | #FFFFFF | (255,255,255) | (-°, 0%, 100%) |
| Black | #000000 | (0,0,0) | (-°, -%, 0%) |
| Green | #009F6B | (0, 159, 107) | (160°, 100%, 63%) |
| Red | #C40233 | (196,2,51) | (345°, 99%, 77%) |
| Yellow | #FFD300 | (255, 211, 0) | (50°, 100%, 100%) |
| Blue | #0087BD | (0, 135, 189) | (197°, 100%, 74%) |
External links
- ToyPalette from Loo & Cox, a web application for generating color palettes from images. NCS color analysis of digital image.