In the visual arts, color theory is a body of practical
guidance to color
mixing and the visual effects of a specific color combination. There are also
definitions (or categories) of colors based on the color wheel:
primary
color, secondary color and tertiary
color. Although color theory principles first appeared in the writings of Leone Battista Alberti (c.1435) and the
notebooks of Leonardo da Vinci (c.1490), a tradition of
"colory theory" began in the 18th century, initially within a
partisan controversy around Isaac Newton's theory of color (Opticks, 1704)
and the nature of so-called primary colors. From there it developed as an
independent artistic tradition with only superficial reference to colorimetry
and vision
science.
Color abstractions
The foundations of pre-20th-century color theory were built
around "pure" or ideal colors, characterized by sensory experiences
rather than attributes of the physical world. This has led to a number of
inaccuracies in traditional color theory principles that are not always
remedied in modern formulations.
The most important problem has been a confusion between the
behavior of light
mixtures, called additive color, and the behavior of paint or ink or
dye or pigment mixtures, called subtractive
color. This problem arises because the absorption of light by material
substances follows different rules from the perception of light by the eye.
A second problem has been the failure to describe the very
important effects of strong luminance (lightness) contrasts in the appearance
of colors reflected from a surface (such as paints or inks) as opposed to
colors of light; "colors" such as browns or ochres cannot appear in
mixtures of light. Thus, a strong lightness contrast between a mid-valued
yellow paint and a surrounding bright white makes the yellow appear to be green
or brown, while a strong brightness contrast between a rainbow and the
surrounding sky makes the yellow in a rainbow appear to be a fainter yellow, or
white.
A third problem has been the tendency to describe color
effects holistically or categorically, for example as a contrast between
"yellow" and "blue" conceived as generic colors, when most
color effects are due to contrasts on three relative attributes that define all
colors:
- lightness (light vs. dark, or white vs. black),
- saturation (intense vs. dull), and
- hue (e.g., red, orange, yellow, green, blue or purple).
Thus, the visual impact of "yellow" vs.
"blue" hues in visual design depends on the relative lightness and
intensity of the hues.
These confusions are partly historical, and arose in
scientific uncertainty about color perception that was not resolved until the
late 19th century, when the artistic notions were already entrenched. However,
they also arise from the attempt to describe the highly contextual and flexible
behavior of color perception in terms of abstract color sensations that can be
generated equivalently by any visual media.
Many historical "color theorists" have assumed
that three "pure" primary colors can mix all possible colors,
and that any failure of specific paints or inks to match this ideal performance
is due to the impurity or imperfection of the colorants. In reality, only
imaginary "primary colors" used in colorimetry can "mix" or
quantify all visible (perceptually possible) colors; but to do this, these
imaginary primaries are defined as lying outside the range of visible colors;
i.e., they cannot be seen. Any three real "primary" colors of light,
paint or ink can mix only a limited range of colors, called a gamut, which is
always smaller (contains fewer colors) than the full range of colors humans can
perceive.
Historical background
Color theory was originally formulated in terms of three
"primary" or "primitive" colors—red, yellow and blue (RYB)—because
these colors were believed capable of mixing all other colors. This color
mixing behavior had long been known to printers, dyers and painters, but these
trades preferred pure pigments to primary color mixtures, because the mixtures
were too dull (unsaturated).
The RYB primary colors became the foundation of 18th century
theories of color vision, as the fundamental sensory qualities
that are blended in the perception of all physical colors and equally in the
physical mixture of pigments or dyes. These theories were enhanced by
18th-century investigations of a variety of purely psychological color effects,
in particular the contrast between "complementary" or opposing hues
that are produced by color afterimages and in the contrasting shadows in
colored light. These ideas and many personal color observations were summarized
in two founding documents in color theory: the Theory of Colours (1810) by the
German poet and government minister Johann Wolfgang von Goethe, and The
Law of Simultaneous Color Contrast (1839) by the French industrial chemist Michel Eugène Chevreul.
Subsequently, German and English scientists established in
the late 19th century that color perception is best described in terms of a
different set of primary colors—red, green and blue violet (RGB)—modeled
through the additive mixture of three monochromatic lights. Subsequent research
anchored these primary colors in the differing responses to light by three
types of color receptors or cones in the retina (trichromacy).
On this basis the quantitative description of color mixture or colorimetry
developed in the early 20th century, along with a series of increasingly
sophisticated models of color space and color perception, such as the opponent
process theory.
Across the same period, industrial chemistry radically
expanded the color range of lightfast synthetic pigments, allowing for
substantially improved saturation in color mixtures of dyes, paints and inks.
It also created the dyes and chemical processes necessary for color
photography. As a result three-color printing became aesthetically and
economically feasible in mass printed media, and the artists' color theory was
adapted to primary colors most effective in inks or photographic dyes: cyan, magenta, and yellow (CMY). (In
printing, dark colors are supplemented by a black ink, known as the CMYK system; in both
printing and photography, white is provided by the color of the paper.) These
CMY primary colors were reconciled with the RGB primaries, and subtractive color
mixing with additive color mixing, by defining the CMY primaries as substances
that absorbed only one of the retinal primary colors: cyan absorbs only
red (−R+G+B), magenta only green (+R−G+B), and yellow only blue violet
(+R+G−B). It is important to add that the CMYK, or process, color printing is
meant as an economical way of producing a wide range of colors for printing,
but is deficient in reproducing certain colors, notably orange and slightly
deficient in reproducing purples. A wider range of color can be obtained with
the addition of other colors to the printing process, such as in Pantone's Hexachrome
printing ink system (six colors), among others.
Munsell's color system represented as a three-dimensional
solid showing all three color making attributes: lightness, saturation
and hue.
For much of the 19th century artistic color theory either
lagged behind scientific understanding or was augmented by science books
written for the lay public, in particular Modern Chromatics (1879) by
the American physicist Ogden Rood, and early color atlases developed by Albert
Munsell (Munsell Book of Color, 1915, see Munsell color system) and Wilhelm
Ostwald (Color Atlas, 1919). Major advances were made in the early 20th
century by artists teaching or associated with the German Bauhaus, in
particular Wassily Kandinsky, Johannes
Itten, Faber Birren and Josef Albers, whose writings mix speculation with an
empirical or demonstration-based study of color design principles.
Contemporary color theory must address the expanded range of
media created by digital media and print management systems, which
substantially expand the range of imaging systems and viewing contexts in which
color can be used. These applications are areas of intensive research, much of
it proprietary; artistic color theory has little to say about these complex new
opportunities.
Traditional color theory
Complementary colors
Chevreul's 1855 "chromatic diagram" based on the RYB
color model, showing complementary colors and other relationships
Main article: Complementary color
For the mixing of colored light, Isaac Newton's color wheel
is often used to describe complementary colors, which are colors which cancel
each other's hue to produce an achromatic (white, gray or black) light mixture.
Newton offered as a conjecture that colors exactly opposite one another on the
hue circle cancel out each other's hue; this concept was demonstrated more thoroughly
in the 19th century.
A key assumption in Newton's hue circle was that the
"fiery" or maximum saturated hues are located on the outer
circumference of the circle, while achromatic white is at the center. Then the
saturation of the mixture of two spectral hues was predicted by the straight
line between them; the mixture of three colors was predicted by the
"center of gravity" or centroid of three triangle points, and so on.
Primary, secondary, and tertiary colors of the RYB
color model
According to traditional color theory based on subtractive primary colors and the RYB
color model, which is derived from paint mixtures, yellow mixed with
violet, orange mixed with blue, or red mixed with green produces an equivalent
gray and are the painter's complementary colors. These contrasts form the basis
of Chevreul's
law of color contrast: colors that appear together will be altered as if mixed
with the complementary color of the other color. Thus, a piece of yellow fabric
placed on a blue background will appear tinted orange, because orange is the
complementary color to blue.
However, when complementary colors are chosen based on
definition by light mixture, they are not the same of the artists' primary
colors. This discrepancy becomes important when color theory is applied across
media. Digital color management uses a hue circle defined around the additive primary colors (the RGB
color model), as the colors in a computer monitor are additive mixtures of
light, not subtractive mixtures of paints.
One reason the artist's primary colors work at all is that
the imperfect pigments being used have sloped absorption curves, and thus
change color with concentration. A pigment that is pure red at high
concentrations can behave more like magenta at low concentrations. This allows
it to make purples that would otherwise be impossible. Likewise, a blue that is
ultramarine at high concentrations appears cyan at low concentrations, allowing
it to be used to mix green. Chromium red pigments can appear orange, and then
yellow, as the concentration is reduced. It is even possible to mix very low
concentrations of the blue mentioned and the chromium red to get a greenish
color. This works much better with oil colors than it does with watercolors and
dyes.
So the old primaries depend on sloped absorption curves and
pigment leakages to work, while newer scientifically derived ones depend solely
on controlling the amount of absorption in certain parts of the spectrum.
Another reason the correct primary colors were not used by
early artists is that they were not available as durable pigments. Modern
methods in chemistry were needed to produce them.
Warm vs. cool colors
The distinction between 'warm' and 'cool' colors has been
important since at least the late 18th century. It is generally not remarked in
modern color science or colorimetry in reference to painting, but is still used
in design practices today. The contrast, as traced by etymologies in the Oxford English Dictionary, seems related
to the observed contrast in landscape light, between the "warm"
colors associated with daylight or sunset and the "cool" colors associated
with a gray or overcast day. Warm colors are often said to be hues from red
through yellow, browns and tans included; cool colors are often said to be the
hues from blue green through blue violet, most grays included. There is
historical disagreement about the colors that anchor the polarity, but
19th-century sources put the peak contrast between red orange and greenish
blue.
Color theory has described perceptual and psychological
effects to this contrast. Warm colors are said to advance or appear more active
in a painting, while cool colors tend to recede; used in interior design or
fashion, warm colors are said to arouse or stimulate the viewer, while cool
colors calm and relax. Most of these effects, to the extent they are real, can
be attributed to the higher saturation and lighter value of warm pigments in
contrast to cool pigments. Thus, brown is a dark, unsaturated warm color that
few people think of as visually active or psychologically arousing.
Contrast the traditional warm–cool association of color with
the color temperature of a theoretical radiating black body,
where the association of color with temperature is reversed. For instance, the
hottest stars
radiate blue light (i.e., with shorter wavelength and higher frequency) and the
coolest radiate red.
The hottest radiating bodies (e.g. stars) have a
"cool" color while the less hot bodies radiate with a
"warm" color. (Image in mired scale.)
Achromatic colors
Any color that lacks strong chromatic content is said to be unsaturated,
achromatic, or near neutral. Pure achromatic colors include
black, white and all grays; near neutrals include browns, tans, pastels and
darker colors. Near neutrals can be of any hue or lightness.
Neutrals are obtained by mixing pure colors with
white, black or grey, or by mixing two complementary colors. In color theory,
neutral colors are colors easily modified by adjacent more saturated colors and
they appear to take on the hue complementary to the saturated color. Next to a
bright red couch, a gray wall will appear distinctly greenish.
Black and white have long been known to combine well with
almost any other colors; black decreases the apparent saturation or brightness
of colors paired with it, and white shows off all hues to equal effect.
Tints and shades
When mixing colored light (additive color models), the
achromatic mixture of spectrally balanced red, green and blue (RGB) is always
white, not gray or black. When we mix colorants, such as the pigments in paint
mixtures, a color is produced which is always darker and lower in chroma, or
saturation, than the parent colors. This moves the mixed color toward a neutral
color—a gray or near-black. Lights are made brighter or dimmer by adjusting
their brightness, or energy level; in painting, lightness is adjusted through
mixture with white, black or a color's complement.
It is common among some painters to darken a paint color by
adding black paint—producing colors called shades—or lighten a color by
adding white—producing colors called tints. However it is not always the
best way for representational painting, as an unfortunate result is for colors
to also shift in hue. For instance, darkening a color by adding black can cause
colors such as yellows, reds and oranges, to shift toward the greenish or
bluish part of the spectrum. Lightening a color by adding white can cause a
shift towards blue when mixed with reds and oranges. Another practice when
darkening a color is to use its opposite, or complementary, color (e.g.
purplish-red added to yellowish-green) in order to neutralize it without a
shift in hue, and darken it if the additive color is darker than the parent
color. When lightening a color this hue shift can be corrected with the
addition of a small amount of an adjacent color to bring the hue of the mixture
back in line with the parent color (e.g. adding a small amount of orange to a
mixture of red and white will correct the tendency of this mixture to shift slightly
towards the blue end of the spectrum).
Split primary colors
In painting and other visual arts, two-dimensional color
wheels or three-dimensional color
solids are used as tools to teach beginners the essential relationships
between colors. The organization of colors in a particular color model depends
on the purpose of that model: some models show relationships based on human
color perception, whereas others are based on the color mixing properties
of a particular medium such as a computer display or set of paints.
This system is still popular among contemporary painters, as
it is basically a simplified version of Newton's geometrical rule that colors
closer together on the hue circle will produce more vibrant mixtures. However,
with the range of contemporary paints available, many artists simply add more
paints to their palette as desired for a variety of practical reasons. For
example, they may add a scarlet, purple and/or green paint to expand the
mixable gamut; and
they include one or more dark colors (especially "earth" colors such
as yellow ochre or burnt sienna) simply because they are convenient to have
premixed. Printers commonly augment a CYMK palette with spot
(trademark specific) ink colors.
Color harmony
It has been suggested that "Colors seen together to
produce a pleasing affective response are said to be in harmony".However,
color harmony is a complex notion because human responses to color are both
affective and cognitive, involving emotional response and judgement. Hence, our
responses to color and the notion of color harmony is open to the influence of
a range of different factors. These factors include individual differences (such
as age, gender, personal preference, affective state, etc.) as well as
cultural, sub-cultural and socially-based differences which gives rise to
conditioning and learned responses about color. In addition, context always has
an influence on responses about color and the notion of color harmony, and this
concept is also influenced by temporal factors (such as changing trends) and
perceptual factors (such as simultaneous contrast) which may impinge on human
response to color. The following conceptual model illustrates this 21st century
approach to color harmony:
Wherein color harmony is a function (f) of the
interaction between color/s (Col 1, 2, 3, …, n) and the factors that
influence positive aesthetic response to color: individual differences (ID)
such as age, gender, personality and affective state; cultural experiences (CE),
the prevailing context (CX) which includes setting and ambient lighting;
intervening perceptual effects (P) and the effects of time (T) in
terms of prevailing social trends.
In addition, given that humans can perceive over 2.8 million
different hues, it has been suggested that the number of possible color
combinations is virtually infinite thereby implying that predictive color
harmony formulae are fundamentally unsound. Despite this, many color theorists
have devised formulae, principles or guidelines for color combination with the
aim being to predict or specify positive aesthetic response or "color
harmony". Color wheel models have often been used as a basis for color
combination principles or guidelines and for defining relationships between
colors. Some theorists and artists believe juxtapositions of complementary
color will produce strong contrast, a sense of visual tension as well as
"color harmony"; while others believe juxtapositions of analogous
colors will elicit positive aesthetic response. Color combination guidelines
suggest that colors next to each other on the color wheel model (analogous
colors) tend to produce a single-hued or monochromatic color experience and
some theorists also refer to these as "simple harmonies". In
addition, split complementary color schemes usually depict a modified
complimentary pair, with instead of the "true" second color being
chosen, a range of analogous hues around it are chosen, i.e. the split
compliments of red are blue-green and yellow-green. A triadic color scheme
adopts any three colors approximately equidistant around a color wheel model.
Feisner and Mahnke are among a number of authors who provide color combination
guidelines in greater detail.
Color combination formulae and principles may provide some
guidance but have limited practical application. This is because of the
influence of contextual, perceptual and temporal factors which will influence
how color/s are perceived in any given situation, setting or context. Such
formulae and principles may be useful in fashion, interior and graphic design,
but much depends on the tastes, lifestyle and cultural norms of the viewer or
consumer.
As early as the ancient Greek philosophers, many theorists
have devised color associations and linked particular connotative meanings to
specific colors. However, connotative color associations and color symbolism
tends to be culture-bound and may also vary across different contexts and
circumstances. For example, red has many different connotative and symbolic
meanings from exciting, arousing, sensual, romantic and feminine; to a symbol
of good luck; and also acts as a signal of danger. Such color associations tend
to be learned and do not necessarily hold irrespective of individual and
cultural differences or contextual, temporal or perceptual factors. It is
important to note that while color symbolism and color associations exist,
their existence does not provide evidential support for color psychology or
claims that color has therapeutic properties.
Current status
Color theory has not developed an explicit explanation of
how specific media affect color appearance: colors have always been defined in
the abstract, and whether the colors were inks or paints, oils or watercolors, transparencies
or reflecting prints, computer
displays or movie theaters, was not considered especially
relevant. source
insertJosef Albers investigated the effects of relative
contrast and color saturation on the illusion of transparency, but this is an
exception to the rule. Known for his color theory paintings of the 1970s, Frederick
Spratt created diptychs consisting of flat rectangular panels of two
different monochrome colors.
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