In the visual arts, color theory or colour
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 over Isaac Newton's
theory of color (Opticks, 1704) and the nature
of 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 different 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,
ink, 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:
Value, (light vs. dark, or white vs. black),
Chroma,[saturation, purity, strength, intensity]
(intense vs. dull), and
Hue (e.g. the name of the color family:red,
yellow, green, cyan, blue and magenta).Thus,
the visual impact of "yellow" vs. "blue" hues
in visual design depends on the relative lightness
and saturation 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 Johann
Wolfgang von Goethe, and The Law of Simultaneous
Color Contrast (1839) by the French industrial
chemist Michel Eugène Chevreul. Charles Hayter
published A New Practical Treatise on the
Three Primitive Colours Assumed as a Perfect
System of Rudimentary Information (London
1826), in which he described how all colours
could be obtained from just three.
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.
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.
== Traditional color theory ==
=== 
Complementary colors ===
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.
According to traditional color theory based
on subtractive primary colors and the RYB
color model, yellow mixed with purple, 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 as the artists' primary colors.
This discrepancy becomes important when color
theory is applied across media. Digital color
management uses a hue circle defined according
to 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. 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.
This contrast is further seen in the psychological
associations of colors with the Relativistic
Doppler effect seen in astronomical objects.
Traditional psychological associations, where
warm colors are associated with advancing
objects and cool colors with receding objects,
are directly opposite those seen in astrophysics,
where stars or galaxies moving towards our
viewpoint from Earth are blueshifted (advancing)
and stars or galaxies moving away from Earth
are redshifted (receding).
=== Achromatic colors ===
Any color that lacks strong chromatic content
is said to be unsaturated, achromatic, near
neutral, or neutral. Near neutrals include
browns, tans, pastels and darker colors. Near
neutrals can be of any hue or lightness. Pure
achromatic, or neutral colors include black,
white and all grays.
Near neutrals are obtained by mixing pure
colors with white, black or grey, or by mixing
two complementary colors. In color theory,
neutral colors are easily modified by adjacent
more saturated colors and they appear to take
on the hue complementary to the saturated
color; e.g., 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 CMYK 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 judgment.
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:
Color harmony
=
f
(
Col
1
,
2
,
3
,
…
,
n
)
⋅
(
I
D
+
C
E
+
C
X
+
P
+
T
)
{\displaystyle {\text{Color harmony}}=f({\text{Col}}1,2,3,\dots
,n)\cdot (ID+CE+CX+P+T)}
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 (or formulas)
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 complementary pair, with
instead of the "true" second color being chosen,
a range of analogous hues around it are chosen,
i.e. the split complements 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.
=== Formulae ===
There are tried and true formulae for finding
colour harmony. To use these formulas all
that is needed is to choose a section (or
sections) of the color wheel.
==== Monochromatic ====
The monochromatic formula chooses only one
color (or hue). Variations of the color are
created by changing the value and saturation
of the color. Since only one hue is used,
the color and its variations are guaranteed
to work.
== Current status ==
Colour 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. Josef Albers investigated the effects
of relative contrast and color saturation
on the illusion of transparency, but this
is an exception to the rule.
== See also
