Color theory

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Color Theory
SOLO HERMELIN
Updated: 30.09.10http://www.solohermelin.com

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Table of Content
SOLO
Color Theory

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Visible Light
SOLO
Color Theory

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Visible Light
SOLO
Color Theory

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SOLO Optics - Eye
The human eye is a camera
The human eye is able to detect from about 390 to
780 nanometers, defining the visual spectrum
http://www.olympusmicro.com/primer/anatomy/introduction.html

Color TheorySOLO
Human Eye Color Sensitivity
• Maximal Luminance response
at ~ 5 cycles/degrees
• Little Luminance response
above ~ 100 cycles/degrees
• Little Luminance response
at low frequencies
Humans are bad at estimating
absolute luminance levels as
long as they do not change with
time.

Color TheorySOLO
Human Eye Color Sensitivity
HUMAN EYE COLOR SENSITIVITY & PERCEPTION
Human Eye contains Rods ( which see Black & White ) &
3 Types of Color Sensitive Cones - sensitive to
"Blue" ( Violet ), "Green" ( Cyan ), & "Red" ( Green ).
By Cone Types combining relative Light Intensities, Color is perceived.
Combined response of Cones is Eye Luminous Efficiency.
Individual differences in Visual Sensitivity result in different Color Perception

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SOLO Optics - Eye
1=Iris The colored part of the eye located between the Lens and
Cornea. It regulates the entrance of the light.
2 = Cornea The transparent, blood-free tissue covering the
central front of the eye that initially refracts or bends light rays
as light enters the eye. Contact lenses are fitted over the Cornea.
3 = Retina The innermost layer of the eye, a neurological tissue,
which receives light rays focused on it by the Lens. This tissue
contains receptor cells (Rods and Cones) that send electrical
impulses to the brain via the optic nerve when the light rays are
present.
4 = Rods The receptor cells which are sensitive to light and are
located in the Retina of the eye. They are responsible for night
vision, as non-color vision in low level light.
5 = Cones The receptor cells which are sensitive to light and are
located in the Retina of the eye. They are responsible for color
vision. Most humans have three types of cones with spectral
sensitivity in the short (S), middle (M) and long (L) part of the
visible spectrum, and hence are called trichromats. Absorption of
a photon leads to a structural change of photo pigment, which –
through an enzymatic cascade – generates the electrical cone
signal. In this process information about the wavelength of the
photon is lost.
6 = Lens The eye's natural Lens. Transparent, biconvex
intraocular tissue that helps bring rays of light to a focus on the
Retina.
7 = Pupil The opening at the center of the Iris of the eye. It
contracts in a high level of light and when the eye is focused on a
distant object.

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SOLO
Color Theory
Finland - The oldest known color system is credited to astronomer, priest and Neoplatonist
Aron Sigfrid Forsius (1569-1637). In his color circle , between the colors Black and
White, Red has been placed on the one side since the classical antiquity, and Blue on the other;
Yellow then comes between White and Red, pale Yellow between White and Yellow, Orange
between Yellow and Red.
http://www.coloryourcarpet.com/History/ColorHistory.html
The oldest colour system known today that's worth its name originates from the Finnish born
astronomer, priest and Neoplatonist Aron Sigfrid Forsius (died 1637), sometimes also known as
Siegfried Aronsen. Forsius became Professor of Astronomy in Uppsala (Sweden) in 1603, later
moving as a preacher to Stockholm and beyond. He was removed from office in 1619, after being
accused of making astrological prophesies.
Eight years previously, a manuscript had appeared in which Forsius expounded his thoughts about
colours, concluding that they could be brought into a spacial order. This 1611 text lay undiscovered in
the Royal Library in Stockholm until this century, to eventually be presented before the first congress
of the "International Colour Association" in 1969. It was in chapter VII — which was devoted to
sight — of this work on physics that Forsius introduced his colour diagrams. He first of all discusses
the five human senses, explains (for us in rather complicated and incomprehensible terms) how
colours are seen, and then arrives at his colour diagrams, on the basis of which he attempts to provide
a three-dimensional picture. Forsius states:
"Amongst the colours there are two primary colours, white and black, in which all others have their
origin." Forsius is here in agreement with Leonardo da Vinci who, more than three hundred years
earlier, had included black and white amongst the colours, seeing them next to yellow, red, blue and
green as primary colours. Forsius then continues:
http://www.colorsystem.com/projekte/engl/03fore.htm
1611
Aron Sigfrid Forsius
)1569-1637.(

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Optics HistorySOLO
1613
François d'Aguilon (also d'Aguillon or Aguilonius) (1546 - 1617) was a Belgian
mathematician and physicist. .... His book, “Opticorum Libri Sex philosophis juxta
ac mathematicis utiles” (Six Books of Optics, useful for philosophers and
mathematicians alike), published in Antwerp in 1613, was illustrated by famous
painter Peter Paul Rubens.
http://en.wikipedia.org/wiki/Fran%C3%A7ois_d'Aguilon
Anguilonius’ system uses three basic colours, and can thus be seen
as the forerunner of other systems which function in a similar way.
In the pure combination of colors, he dispenses with the fourth,
green, which had already caused difficulties for Leonardo da Vinci,
but not without granting it a special position. In the same way as red
(above), green is placed in the middle (although beneath). Both
colours therefore stand opposite one another, and rightly so, since
they do this in a complementary way, as Aguilonius quietly implies
when he allocates a tip (a point) to red, whilst green is allowed to
extend outwards as a bow. Thus, a restrained point of colour stands
opposite the continuous colored line, to be combined using the
stepped diagram.
http://www.colorsystem.com/projekte/engl/04ague.htm
François d‘Aguilon's color mixing theory (1613)
http://www.handprint.com/HP/WCL/color6.html
Peter Paul Rubens frontispiece of Aguilon's book
François d'Aguilon
1567-1617

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SOLO
Color Theory
Color music intended for instrumental performance in conjunction
with a simultaneous projection of changing colors onto a screen.
Athanasius Kircher said that each musical sound has a necessary,
objective correspondence to a certain color.
1646
Athanasius Kircher published in 1646 a book, specifically devoted to colours — The Great Art
of Light and Shadow ("Ars magna lucis et umbrae"). The first two words of the Latin title clearly
point to the art of Raimundus Lullus, which will be described later (Ars magna). No wonder,
therefore, that his system provides a firm idea of mixed colours, characterised by semi-circular
bows.
The basis for all combinations is a linear construction which, apart from white (albus) and black
(niger), operates with three colours, namely yellow (flavus), red (rubeus) and blue (caeruleus). We
have no need to account for all arrangements here, and neither should we attempt the translation of
all the many new names — subrubeus, for example, or fuscus, or incarnatus. The special position
of green (virides) is noteworthy, however: like red, green is placed in the centre, although on the
plane of the mixed colours, and not the pure colours. Green is located at the overlap of yellow and
blue. If we draw the bows running from white so that they are directed upwards, and the curves
running to black so that they are directed downwards, an image will be created which resembles the
Chinese Yin-Yang (to create this symbol, we need only retain the route through red, while omitting
the lines passing through yellow and blue). As our illustration shows, all the colour points of the
system can then be reached from white and black; with that it's author's fundamental view will
become apparent. In fact, Kircher views colour as a "genuine product of light and shadow", as he
says in the forward to his 1646 book, adding that colour is "shadowed light" and "everything in the
world is visible only by means of shadowed light or illuminated shadow."
)1601–1680(

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SOLO
Color Theory
England - Isaac Newton (1642-1726) devises the first color
wheel . His theory "Optics" had the right idea, dividing the prism
and bringing it back together again. However he choses the wrong
colors, magenta and cyan were missing. Magenta doesn't show up
in a crystal spectrum. It was 32 years later before his color theory
was published.
English physicist, mathematician, and natural philosopher,
considered one of the most important scientists of all time.
Newton showed that a prism could break up white light into
a range of colors.
Newton used the seven color names red, orange, yellow,
green, blue, indigo, and violet for segments of the spectrum by
analogy with the seven notes of the musical scale.
Isaac Newton
)1642-1726(
http://home.wanadoo.nl/paulschils/08.00.html
1666

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SOLO
Color Theory
1731-France - Jacques Christopher Le Blon,
(1667-1742), invented the fundamental three-color
palette and demonstrated his system with many dyes,
however he did not extend his ideas to a properly
organised colour-system.
Jacob Christoph Le Blon was a German-born painter and engraver
who invented the system of three-color and four-color printing
(similar to the modern CMYK system).He used several metal plates
(each for an individual color) for making prints with a wide range of
colors. His methods formed the foundation for modern color printing.
His names are sometimes spelled Jakob, Jacques, Christophe, Leblon,
Le Blond.
1731
The First Tri Color Printing Process

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SOLO 1740Color History
Louis Bertrand Castel (15 November 1688 – 9 January 1757)
was a French mathematician born in Montpellier, and entered the
order of the Jesuits in 1703. Having studied literature, he
afterwards devoted himself entirely to mathematics and natural
philosophy. He wrote several scientific works, that which attracted
most attention at the time being his “Optique des Couleurs”
(1740), or treatise on the melody of colors
Louis Bertrand Castel published a criticism of Newton's spectral
description of prismatic colour in which he observed that the
colours of white light split by a prism depended on the distance
from the prism, and that Newton was looking at a special case. It
was an argument that Goethe later (1810) developed in his Theory
of Colours
Castel himself theorized that vibrations produced color, just as they
produced sounds. He concluded, therefore, that colors and sounds
were analogous, which led him to attempt to develop the “ocular
harpsichord” described in this book. The harpsichord was
supposed to display colors in correspondence with particular notes.
He had originally meant for the harpsichord to remain theoretical,
but the skepticism of his critics caused him to spend thirty years
trying to construct such an instrument.

SOLO
Color Theory
1755-Germany - Mathametician Tobias Mayer (1723-
1762) develops color theory by math, but his selection of
triad colors (Red, Blue and Yellow) created . Two years
later, Mayer tried to identify the exact number of colors
which the eye is capable of perceiving.
1755
In 1758 — more than half a century after
Newton's Opticks had appeared — the German
mathematician and astronomer Tobias Mayer
(1723-1762) gave a lecture to the Göttingen
Academy of Science entitled "De affinitate colorum
commentatio" (historical system), in which he tried
to identify the exact number of colours which the
eye is capable of perceiving. He chose red, yellow
and blue as his basic colours, and vermillion,
massicot and azurite as their representatives
amongst the pigments. Black and white were
considered to be the agents of light and darkness,
which either lighten of darken the colours.
Tobias Mayer
)1723-1762(

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SOLO Color Theory
1766-England - The first known use of a color wheel was
developed by Moses Harris (1731-1785), this one had Red,
Yellow and Blue but he included Black as the only neutral.
1766
In 1766, one hundred years after Newton's separation of white light through a prism, a book appeared in England
with the title The Natural System of Colours (historical illustration). In this work, Moses Harris (1731-1785), the
English entomologist and engraver, examines the work of Isaac Newton and attempts to reveal the multitude of
colours which can be created from three basic ones. As a naturalist, Harris wishes to understand the relationships
between the colours, and how they are coded, and his book attempts to explain the principles, "materially, or by the
painters art", by which further colours can be produced from red, yellow and blue.
Harris builds upon the discovery by the Frenchman Jacques Christophe Le Blon (1667-1742). Le Bon is credited
with the invention of colour printing. In 1731, during the course of his work, he observed something which every
school child now learns: namely, that three paints coloured red, yellow and blue are sufficient to produce all other
colours. Although Le Blon invented the fundamental three-colour palette and demonstrated his system with many
dyes, he did not extend his ideas to a properly organised colour-system; that was for Harris to accomplish. Harris
introduced the first printed colour-circle in 1766, specifying his primary colours very exactly: red was cinnabar, which
could be made from sulphur and mercury; yellow was King's yellow (an artificial orpiment); and ultramarine was
used for blue. Harris distinguished between the harmony of the "prismatic or primitive colours", which are assigned a
"prismatic circle" (we show this to the left, large) and "compound colours", which are allotted their own circle (to the
right, and smaller). The word "prismatic" could at first lead to confusion. In fact, Harris did not mean the spectral
colours observed by Newton after light had passed through his prism and then arranged in a circle; he meant the
unmixed pigments ("grand or principal colours"). A mixture ("compound") of the three basic colours will result in
the three intermediate colours ("mediates") mentioned: orange, green and purple, which also appear in the prismatic
circle and are all brought to life with natural descriptions ("fruit or flower"). According to Harris, the three main
colours, red, yellow and blue, are: "the greatest opposites in quality to each other and naturally take their places at the
greatest distance from each other in the circle". In order to arrange this "greatest distance" evenly within the circle,
Harris requires an even number of circle segments (illustration), and Newton's seventh colour, indigo, is therefore
dispensed with.

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SOLO
Color Theory 1772
Johann Heinrich
Lambert
(1728-1777)
Germany - Astronomer J. Heinrich
Lambert (1728-1777) presented the
first three-dimensional color-system
In his main philosophical work, New Organon (1764), Lambert
studied the rules for distinguishing subjective from objective
appearances. This connects with his work in the science of optics. In
1760, he published a book on light reflection in Latin, the
Photometria, in which the word albedo was introduced and the Beer–
Lambert law was formulated that describes the way in which light is
absorbed. Lambert also wrote a classic work on perspective and also
contributed to geometrical optics.
In the course of his deliberations, he consulted measurements taken by Tobias Mayer in
Göttingen, and thus became aware of Mayer's colour-triangle dating from 1758, the publication
of which he was to subsequently support. Lambert recognised that Mayer had discovered a means
of constructing and naming many of the possible colours, and at the same time also recognised
that, to extend its coverage to include their full abundance, the only element missing from this
triangle was depth. After carrying out his own experiments, Lambert suggested a pyramid
constructed from a series of triangles (historical illustration) to accommodate the full richness of
natural colours in one geometrical form. These differ from Mayer's triangles not only in their
size, but also in the position of black

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SOLO
Color Theory
1772-Austria - Ignaz Schiffermüller
published his color-circle in Vienna based on
four colours, red, blue, green and yellow
A color-circle based on four colors, red, blue, green
and yellow, divided into 3 x 4 = 12 segments.
His color-circle is provided with fanciful names:
blue, sea-green, green, olive-green, yellow, orange-
yellow, fire-red, red, crimson, violet-red, violet-blue
and fire-blue.
1772
In the same year that J.H.Lambert constructed his colour pyramid and demonstrated for the first time
that the complete fullness of colours can only be reproduced within a three dimensional system,
another colour circle was published in Vienna by Ignaz Schiffermüller. The circumference of
Schiffermüller's circle is filled with twelve colours to which he has given some very fanciful names:
blue, sea-green, green, olive-green, yellow, orange-yellow, fire-red, red, crimson, violet-red, violet-blue
and fire-blue. The transitions are continuous — in marked contrast to Moses Harris — and the three
primary colours of blue, yellow and red are not placed at equal distances from each other; between
them come three kinds of green, two kinds of orange and four variations of violet (excluding the
secondary colour violet). Schiffermüller selects a total of 12 colours and thus draws upon the system
originated by the French Jesuit Louis Bertrand Castel, who had published his Optique des couleurs in
1740 in order to extend Newton's circle with its seven colours up to twelve. His choice sounds unusual:
bleu, celadon (pale green), vert, olive, jaune, fauve (pale red), nacarat (orange), rouge, cramoisi, violet,
agathe (agate blue) and bleu violant. Castel linked his system to music — more specifically, the twelve
semi-tones of the musical scale.
Ignaz Schiffermüller
1726-1806

SOLO
Color Theory
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.
Goethe's color wheel from his 1810
Theory of Colours
Michel Eugène
Chevreul
1786 – 1889 !
Johann Wolfgang von
Goethe
1749 - 1832

SOLO
Color Theory
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.

SOLO
Color Theory
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.
Ogden Nicholas
Rood
)1831–1902(
Albert Henry
Munsell
)1858–1918(
Friedrich
Wilhelm Ostwald
)1853–1932(
Johannes
Itten
(1888 --1967)

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SOLO
Color Theory
Flower Color Wheel

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SOLO
Thomas Young
1773-1829
1807
In 1807 physicist Thomas Young’s theory that all colors can
be mixed from the three basic colors of red, blue and yellow.
An authority on the mechanism of vision and on optics, he
stated (1807) a theory of color vision now known as the
Young-Helmholtz Theory, studied the structure of the eye,
and described the defect called astigmatism
http://www.infoplease.com/ce6/people/A0853151.html
Helmholtz later discovered that people with
normal color vision need three wavelengths of light
to create different colors.
Helmholtz used color-matching experiments where
participants would alter the amounts of three
different wavelengths of light to match a test color
http://psychology.about.com/od/sensationandperception/f/trichrom.htm
http://physics.nad.ru/Physics/English/optics.htm
Run This
Color Theory

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SOLO
Color Theory
At the beginning of the 19th century, the Englishman James Sowerby (1757 - 1822) — already
distinguished as an author of books on botany and natural history — introduced his color system,
which he dedicated to "the great Isaac Newton". It had the lengthy title A New Elucidation of Colours,
Original Prismatic and Material: Showing Their Concordance in the Three Primitives, Yellow, Red
and Blue: and the Means of Producing, Measuring and Mixing Them: with some Observations on the
Accuracy of Sir Isaac Newton. Sowerby sets himself two tasks with this work, which appeared in
London in 1809: he wishes to re-emphasize the significance of brightness and darkness, which after
Newton had fallen into obscurity; and he wishes to clarify the difference which exists between colors.
Johann Heinrich Lambert has already emphasized that the colors of light and the colors of materials
behave in a different way when mixed. In his system, Sowerby assumes the existence of three basic
colors, red, yellow and blue (he actually selects gamboges — a poisonous yellow sap from Asiatic
plants — carmine and Prussian blue, which are then combined).
The sketches emphasize the three parts on which Sowerby's theory rests and express the stabilizing
continuity which can exist between them. Incidentally, Sowerby's attempt to transform Newton's seven
primary colors into three materially render able basic colors attracted the attention of the English
painter William Turner (the two were, in fact, acquainted). Later, in about 1820, Turner followed the
painter Otto Runge in trying to assimilate the system of the three colors red, yellow and blue into a
diurnal pattern (for which there is more than just one possibility, as was soon apparent).
Sowerby's text describes the optical mixtures which result when narrow and tightly packed strips of
primary color are applied to paper
James Sowerby
)1757-1822(
1809

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SOLO
Goethe’s color wheel from his 1810 Theory of Colours
1810
Johann Wolfgang von Goethe
1749 - 1832
“Theory of Colors” (original German title, Zur Farbenlehre) is
a book by Johann Wolfgang von Goethe published in
1810. The work comprises three sections:
i) a didactic section in which Goethe presents his own
observations,
ii) a polemic section in which he makes his case against
Newton, and
iii) an historical section.
It contains some of the earliest and most accurate
descriptions of phenomena such as colored shadows,
refraction, and chromatic aberration.
http://en.wikipedia.org/wiki/Theory_of_Colours
Light spectrum, from Theory of Colors –
Goethe observed that color arises at the
edges, and the spectrum occurs where
these colored edges overlap
Color Theory

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SOLO
Color Theory
In 1810, the year in which Goethe's Theory of Colors with its
color-circle (original drawing of Goethe) was published, the
painter Philipp Otto Runge presented his work on a "color-
sphere". As suggested by its title, Runge was concerned with
the "construction of the proportion of all mixtures of the colors
with each other, and their complete affinity" original drawing
of Runge). Runge's sphere appeared in the year of his death —
the painter died at the age of only thirty three. His color system,
once described in an encyclopedia as "a blend of scientific-
mathematical knowledge, mystical-magical combinations and
symbolic interpretations", represented the sum total of his
endeavors. Runge's color globe is seen as marking the
temporary end to a development which had led from linear
colors via the two-dimensional color-circles to a special
arrangement of colors in the form of a pyramid.
Philipp Otto Runge Color Sphere
Philipp Otto Runge
)1777–1810(
1810

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SOLO
Color Theory 1839
Michel-Eugène Chevreul a chemist developed many of
the laws of color harmony generally accepted today.
He published his researches on color contrasts (De la loi du
contraste simultané des couleurs, in 1839; the 1854 English
translation is titled The Principles of Harmony and Contrast of
Colors).
Michel Eugène Chevreul
1786 – 1889 !
Chevreul discovered some of the problems involved with the
interaction of colors on a surface. Specifically, Chevreul was
concerned with the way that the depth of a black dye changed
with the different colors that surrounded it. He studied this
problem carefully and produced his "Law of the Simultaneous
Contrast of Colors," stated as such:
"In the case where the eye sees at the same time two contiguous
colors, they will appear as dissimilar as possible, both in their
optical composition and in the height of their tone."

28
SOLO
Color Theory
Thomas Young (1773-1829) argued that there was a limited rather than
infinite number of different retinal "particles" at every point on the retina
to respond to light. He suggested that there might be three such particles
only, a view later validated by science. His key contribution to color vision
science may have been to restate Palmer's concept of spectral sensitivity
Hermann von Helmholtz (1821-1894) championed Young's idea that
retinal particles varied in the light to which they were "maximally
sensitive." As a result, the trichromatic theory of colour vision also came
to be known as Young-Helmholtz Theory. Influenced by his colour
mixing experiments, however, Helmholtz could not accept the notion that
there could be fewer than five colour primaries. Thus, he failed to accept
the three retinal primaries proposed by Young.
1851
1807

29
SOLO
Color Theory
Trichromatic color vision
Trichromatic color vision is the ability of humans and
some other animals to see different colors, mediated by
interactions among three types of color-sensing cone
cells. The trichromatic color theory began in the 18th
century, when Thomas Young proposed that color
vision was a result of three different photoreceptors.
Hermann von Helmholtz later expanded on Young's
ideas using color-matching experiments which showed
that people with normal vision needed three
wavelengths to create the normal range of colors. Each
of the three types of cones in the retina of the eye
contains a different type of photosensitive pigment,
which is composed of a transmembrane protein called
opsin and a light-sensitive molecule called 11-cis
retinal. Each different pigment is especially sensitive to
a certain wavelength of light (that is, the pigment is
most likely to produce a cellular response when it is hit
by a photon with the specific wavelength to which that
pigment is most sensitive). The three types of cones are
L, M, and S, which have pigments that respond best to
light of long (especially 560 nm), medium (530 nm),
and short (420 nm) wavelengths respectively.

SOLO Theory of Colors 1859
In 1859, Maxwell, then 28 years old, presented his Theory of Color Vision, acknowledged as being the origin
of quantitative color measurement (Colorimetry). In this work, Maxwell demonstrates that all colors arise from
mixtures of the three spectral colors — red (R), green (here abbreviated to V [verde]), and blue (B), for example —
on the assumption that the light stimulus can be both added and subtracted. He allocates each of the three main
colors to a corner of a triangle, into which we have then placed a curve of spectral colors which is provided with
technical data. A line of this type will reappear later in the CIE System. This is important, because all associated
insights go back to Maxwell who, with his triangle, introduced the first two-dimensional color system based on
psychophysical measurements.
In 1849 Maxwell began his work on the subject. This work was presented to the Royal Society of Edinburgh in
1855 in his paper entitled, Experiments on Color, as perceived by the Eye, with remarks on Color-blindness.
He demonstrated, using a colored top (figure 5.2.1), that any natural color could be produced from the three
primary colors - red, green and blue. Most of this work was not new and merely reiterated what was already
known. However it was excellently produced and was a good prelude to his later work.
Maxwell's major paper in optics, On the Theory of Color Vision, was presented to the Royal Society of London
in 1860 and was awarded the Rumford Medal. It showed that color blindness was due to individuals being
unable to recognize red light and conclusively proved his theory of three primary colors. Most of the
experiments for this work were conducted in Maxwell's London home with the help of his wife, Katherine
Mary Dewar daughter of the Principle of Marchisal College, Aberdeen. These were wonderfully constructed
and made use of a color box designed by Maxwell himself.
James Clerk
Maxwell
(1831 – 1879)

31
SOLO Photography 1861
James Clerk Maxwell produces the first color
photograph by photographing a subject through red,
yellow, and blue filters, then recombining the images.
Maxwell analysis of color perception led to his invention of
the trichromatic process. The trichromatic process is the
basis modern color photography.
http://micro.magnet.fsu.edu/optics/timeline/people/maxwell.html
http://micro.magnet.fsu.edu/optics/timeline/1834-1866.html
http://www.edinphoto.org.uk/1_P/1_photographers_maxwell.htm
For his demonstration, he arranged for three photographs of a
tartan ribbon to be taken by the professional photographer,
Thomas Sutton. Each was made using a black+white slide.
These slides were exposed respectively through red, green and
blue filters.

32
SOLO
Color Theory
W. Benson, “Principles of the Science of Color”,
Concisely Stated To Aid and Promote Their Useful
Application in the Decorative Art, London 1868;
In 1868, Benson proposed the first of his many color-cubes. He considered
this arrangement to be the "natural system of colors", as the title of Chapter 7
of his Principles of the Science of Color states. At the outset, Benson cited the
preliminary work of Mayer, Runge and Chevreul, but then proceeds in
long sentences to justify his own preference for an alternative geometry.
"In order to use the normal methods of geometrical representation of all
combinations which can be formed from three independent variables, a point
must be chosen which represents zero or black — the absence of all light.
From this point, three lines must be drawn at right angles to each other. Along
these lines, and on all parallel coordinates, the colors red, green and blue shall
increase in intensity, commencing at zero. The intensities of red, green and
blue, which collectively give white, shall be the same, and are therefore
represented by equal distancing along the three right-angled coordinates. The
end points of these three lines will thus be the places for the full red, the full
green and the full blue, while the lines themselves contain the shades of these
three colors towards black... The corner of the cube opposite the black would
be the full white, and the corners lying opposite red, green and blue would be
sea-green, pink and yellow. The central point would be a medium grey." The
fact that pink is given priority over purple is probably connected with its
brightness.
1868

SOLO
1874Theory of Colors
Wilhelm Max Wundt
1832--1920
Wilhem Max Wundt was a student of Helmholtz.
Color space 1893 Color space 1874

SOLO
1876
Theory of Colors
Ernst Wilhelm
von Brücke
(1819—1892)
A change to the perception of colors under the
effects of in-creased light intensity or the
apparent brightness of hues changes as
illumination changes. With increasing
intensity, wavelengths below 500 nm shift
more toward blue, and above 500 hues shift
more toward yellow. Reds become yellowier
with increasing brightness.
Johann Friedrich Wilhelm
von Bezold
(1837- 1907)
Bezold-Brücke Phenomenon
1874

35
SOLO
Rood was well suited to the job of bridging the gap between
art and science, as he had a successful career as a teacher,
scientist, and amateur painter. Rood explained many
concepts that were still relatively unknown, such as the
difference between additive and subtractive color mixing. He
talked much about the physical color spectrum and he
thoroughly described the three color making attributes of
hue, saturation, and value. These three color making
attributes were noticeable absent from Chevreul's work.
Unlike Chevreul's book, Rood's Modern Chromatics is still
considered to be scientifically accurate today.
Ogden Nicholas Rood (1831–1902) was an American
physicist best known for his work in color theory. He studied in
Berlin and Munich before his appointment as Chair of Physics
at Columbia University, a position he held from 1863 until his
death. His book on color theory, Modern Chromatics, with
Applications to Art and Industry, was published in 1879, with
German and French translations appearing in 1880 and 1881,
respectively. Rood divided color into three constants: purity,
luminosity, and hue—equivalent to James Clerk Maxwell's tint,
shade, and hue (Harrison, 640).
Ogden Nicholas Rood
)1831–1902(

SOLO
1883-1897Theory of Colors
Alois Höfler
(1853--1922)
Alois Höfler (1853-1928), the Austrian educationalist and philosopher, produced many
texts on both psychology and general science and made a name for himself by publishing the
Berliner Kant-Ausgabe (1903). In 1897, his textbook Psychologie appeared, in which he
introduced his first color system — a double pyramid with rectangular base (an octahedron).
He later proposed a further, derivative color solid with a triangular base (tetrahedron). White
(W.) and black (BK.) are found at the tips of both constructions, with grey appearing in the
middle.
Höfler also sought a relationship between the harmony of colors and music. In his books, he
explicitly points to the sequence white-grey-black since he discovers here a "quasi-straight
line", meaning a straight line limited at both ends. Such a line, however, appears unfamiliar to
music and musical notes.
The rectangle — the system of four — operates with the four elementary perceived colors:
yellow (Y), red (R), blue (B) and green (G). Of these four psychological colors, only the yellow
reappears, along with cyan (C) and purple (P), in the artists' triangle, which thus contains the
subtractive primary colors.
The purpose of Höfler's arrangement is not to provide an organisational or identification
system, and neither does he consider that color variations can be subordinated, for instance to
the geometrical properties of a sphere. He is more concerned with "certain alternative internal
relationships" between the colors. His color-octahedron not only represents Hering's basic
colors, but also their relationship as opposing colors.
Höfler's solid should be seen as an expression of the relationship between colored sight on the
one hand and the psychological effect of colors on the other. For this reason, many
psychological textbooks have adopted his pyramids to provide information on our perception of
colors.

SOLO
Karl Ewald Konstantin
Hering
)1834–1918(
Hering disagreed with the leading theory developed mostly by
Thomas Young and Hermann von Helmholtz. Helmholtz's theory
stated that the human eye perceived all colors in terms of three
primary colors: red, green, and blue. Hering instead believed that the
visual system worked based on a system of color opponency, a
proposal now widely recognized as correct.
Hering looked more at qualitative aspects of color and said there were
six primary colors, coupled in three pairs: red-green, yellow-blue and
white-black. Any receptor that was turned off by one of these colors,
was excited by its coupled color. This results in six different receptors.
It also explained afterimages. His theory was rehabilitated in the
1970s when Edwin Land developed the Retinex theory that stated that
whereas Helmholtz's colors hold for the eye, in the brain the three
colors are translated into six.

SOLO Color Theory
The Hue is the property of light by which the
color of an Object is classified as Red,
Yellow
or Blue in reference to the spectrum.
Or as a gradation or variety of a color.
Or as the Rainbow color, just like
all the Hue's of the Rainbow
The Hue is the term used in the
world of color for the
classification of Red, Yellow,
Green etc.
Also, although Red and Yellow
are two completely
different, mixing both results is
Orange.
( Orange is sometimes referred
to as Yellow-Red
The continuum of these results in
the color wheel
shown as the diagram.HUE's Form a Color Wheel
Albert Munsell was a art teacher and artist who published a simple color system in 1905 and an atlas of colors in
1915. His book was successful at creating a standardized set of colors that continues to be used by artists and
publishers. to this day. The Munsell standardized colors make it easy for people to communicate in the language of
color. Although other tools exist to define colors, most notably the CIE 1931, they are slightly more difficult to work
with in comparison to the Munsell system. The simplicity of the system as helped it gain wide acceptance by artists,
designers, photography, printers and more
Albert Henry Munsell
)1858–1918(
1905-1915

SOLO Color Theory 1905-1915
The three dimensions of the Munsell color system are:
1. Hue: Related to wavelength or dominant
wavelength. Hue is denoted by a combination of
letters and numbers making up a 100 step scale
(figure 5). There are ten letter categories used to
denote hue, with each of these further subdivided (by
the use of numerals 1 to 10) into ten subgroups. If
the numeral denoting the hue subgroup is 5, then it
can be omitted (eg. 5R is the same hue as R).
2. Value: Value is specified on a numerical scale
from 1 (black) to 10 (white) and this attribute is
related to reflectance and luminosity (or lightness).
3. Chroma: Chroma is the Munsell term corresponding to saturation. It is indicated
numerically on a scale of 0 to the various maxima dependent on the saturation
obtainable with available pigments.
For example, a colour may have a notation 2GY 6/10. This means it is a
green/yellow that is quite close to being a yellow; it has a value of 6 (ie. almost
midway in the black/white scale) and a chroma of 10 (ie. it is saturated).

SOLO Color Theory
Albert Munsell was a art teacher and artist who published a simple color system in 1905 and an atlas of colors in
1915. His book was successful at creating a standardized set of colors that continues to be used by artists and
publishers. to this day. The Munsell standardized colors make it easy for people to communicate in the language of
color. Although other tools exist to define colors, most notably the CIE 1931, they are slightly more difficult to work
with in comparison to the Munsell system. The simplicity of the system as helped it gain wide acceptance by artists,
designers, photography, printers and more
Albert Henry Munsell
)1858–1918(
1905-1915
Some features of the Munsell system
are used in commercially available
paint and pigment mixing guides
like the Color Wheel.

SOLO Color Theory 1914
Paul Klee
(1879 – 1940)
Paul Klee painted his first pure abstract, in the Style of
Kairouan (1914), composed of colored rectangles and a few
circles.[24]
The colored rectangle became his basic building
block, what some scholars associate with a musical note, which
Klee combined with other colored blocks to create a color
harmony analogous to a musical composition. His selection of
a particular color palette emulates a musical key. Sometimes
he uses complementary pairs of colors, and other times
“dissonant” colors, again reflecting his connection with
musicality.
Klee's color theory, based on a continuous principle of movement, stands out as an
individual position in the history of such theories. Starting with the six colors of the
rainbow, he renders this natural phenomenon in a related circle divided into six parts.
The relationship between the colors in the circle results from two different kinds of
movement: a circular movement around the edge and a straight one within the diameter
of the circle, which he refers to as pendular movement. From the circular form, he
derives a triangle of primary colors, which he subsequently expands into an "elemental
star" including the non-colors black and white.

One such three-dimensional arrangement,
which achieved popularity early in the
twentieth century, was that devised by the
Latvian-German scientist Wilhelm Ostwald
(1853-1932), and first published as ‘Die
Farbenfibel’ ('The Color Primer') in Leipzig
in 1916. ‘Die Harmonie der Farben’ ('The
Harmony of Colors') followed in 1918.
Wilhelm Ostwald Color System
Ostwald's color circle consists of a sequence
of 24 hues divided into eight groups of three,
named yellow, orange, red, purple, blue,
turquoise, seagreen and leafgreen. In his
lightness scale, a standard white sample
(denoted a) is linked to a standard black
sample (denoted p) by 13 grey steps, judged
visually to be equal in interval (and lettered b
to o; the sequence is usually abridged to eight
steps, a, c, e, g, i, l and p). Ostwald's color wheel
Wilhelm Ostwald
(1853-1932),

Wilhelm Ostwald Color System
Ostwald's color wheel
One such three-dimensional arrangement, which achieved popularity early in
the twentieth century, was that devised by the Latvian-German scientist Wilhelm
Ostwald (1853-1932), and first published as ‘Die Farbenfibel’ ('The Color
Primer') in Leipzig in 1916. ‘Die Harmonie der Farben’ ('The Harmony of
Colors') followed in 1918.

Wilhelm Ostwald (1853-1932) — who came from the Baltic — received the Nobel
prize for chemistry
Ostwald, who had met Albert H. Munsell in 1905 on a journey to America, attempted to
devise a system — just as the American painter had done — based on perception and
equalising the respective differences between individual colors. Expressed in our modern
technical language, we can say that Ostwald attempted to construct a perceptual color-
system using non-empirical methods. In place of Munsell's three parameters, he selected
an alternative group of variables: namely, color-content, white-content and black-content.
He also introduced the special term "full color", by which he meant a color which
permitted the sensation of one single color-tone (Munsell's "hue") and was not tempered
by white or black. To be more accurate, we could say that a full color is an optimally pure
color — in other words, of maximum saturation and at the same time bright. Full colors
are, of course, ideal colors which cannot be reproduced by actual pigments. (When
Ostwald published his Color Primer, his full colors contained about 5% white and slightly
less black, as he himself admitted.)
We can thus formulate the guiding principle behind Ostwald's theory of color in the
following way: the most universal mixture is the mixture of full colors, white and black.
Each pigmented color can be characterized by specifying the color-content (at a certain
color-hue), white-content and black-content. In his Farbfibel, Ostwald proceeds
systematically, drawing a distinction between chromatic and achromatic colors. He
arranges his achromatic colors in the form of a grey scale along a line containing eight
gradations, which conform to a geometrical sequence. In other words, the influence of
visually dominant white does not decrease uniformly from above downwards, but does so
geometrically, with the perceived mid-point between black and white being characterized
by a proportion of approximately 20% white. (To avoid confusion, we have omitted the
letters used here by Ostwald to identify these gradations.) The basis of the sequence is the
so-called Weber-Fechner Law of Psychophysiology, although its application is technically
limited. In fact, Ostwald abandoned his grey sequence which used this law as a basis.
Friedrich Wilhelm
Ostwald
)1853–1932(

Shinobu Ishihara
(1879--1963)
Shinobu Ishihara created the Ishihara Color Test to detect
Color Blindness.
The Ishihara Color Blindness test – named after a
Japanese Professor at the University of Tokyo – is the most
well known tool to test for red-green color blindness. Mr
Ishihara developed this test almost 100 years ago. It was
first published in 1917 and is used since then to check if
someone is suffering from protanopia or deuteranopia, the
two different kinds of red-green color vision deficiencies.
A collection of 38 plates filled with colored dots build the
base of this test. The dots are colored in different shades of
a color and a number or a line is hidden inside with
different shades of an other color. But enough theory, take
the color blindness test by Mr Ishihara yourself and be
surprised (or not) of the result.
A plate from the Ishihara Test for color
blindness. Can you see the number 74? However,
whether you see the number or not, don’t take
this as a final indication: it is only one plate of
many plates in the full test and the colors on
your computer screen might not be exactly right.
A plate from the Ishihara Test for color blindness. Can
you see the number 12?

Johannes Itten
(1888 --1967)
Johannes Ittens color circle is based on 12 paint colors,
The primary colors Red-Yellow-Blue.
The secondary colors Orange-Green-Violet.
The tertiary colors Yellow/Orange-Red/Orange-Red/Violet-
Blue/Violet-Blue/Green-Yellow/Green.
In science: Ittens names of color are not correct.
From 1919 to 1922, Itten taught at the Bauhaus,
developing the innovative "preliminary course"[
which
was to teach students the basics of material
characteristics, composition, and color. In 1920 Itten
invited Paul Klee and Georg Muche to join him at the
Bauhaus.[4]
He also published a book, The Art of
Color, which describes these ideas as a furthering of
Adolf Hölzel's color wheel. Itten's so called "color
sphere” went on to include 12 colors.

SOLO
Color Theory
Here is an animated RGB color cube. Notice how the colors get lighter as
COLOR HAS THREE DIMENSIONS OR QUALITIES:
*HUE
*VALUE
*INTENSITY
RED YELLOW VIOLET
HUE: The name given to a color.
VALUE: The Lightness or Darkness of a Color
+ =
HUE WHITE TINT
+ =
HUE BLACK SHADE
SHADE: Made by adding black to
a color so that it is darker.
TINT: Made by adding white to
a color so that it is lighter.
INTENSITY: The brightness or dullness of a color.

48
SOLO
Color Theory
Here is an animated RGB color cube. Notice how the colors get lighter as
The Color Wheel
A color circle, based on red, yellow and blue, is traditional in the field of art. Sir Isaac Newton
developed the first circular diagram of colors in 1666. Since then scientists and artists have
studied and designed numerous variations of this concept. Differences of opinion about the
validity of one format over another continue to provoke debate. In reality, any color circle or
color wheel which presents a logically arranged sequence of pure hues has merit.
PRIMARY COLORS Red, Yellow and Blue
In traditional color theory, these are the 3 pigment
colors that can not be mixed or formed by any
combination of other colors. All other colors are derived
from these 3 hues
SECONDARY COLORS Green, Orange
and Purple
These are the colors formed by mixing the primary colors.
TERTIARY COLORS
Yellow-orange, red-orange, red-purple,
blue-purple, blue-green and yellow-green.
These are the colors formed by mixing a primary and a
secondary color. That's why the hue is a two word name,
such as blue-green, red-violet, and yellow-orange.
R e d - v io le t
V io le t
B lu e - v io le tB lu e
B lu e - g r e e n
G r e e n
Y e llo w - g r e e n
Y e llo w
Y e llo w - o r a n g e O r a n g e
R e d - o r a n g e
R e d
R e d - v io le t
V io le t
B lu e - g r e e n
G r e e n
Y e ll o w - g r e e n
Y e ll o w
Y e llo w - o r a n g e O r a n g e
R e d - o r a n g e
R e d
R e d - v i o le t
V io le t
B lu e - g r e e n
G r e e n
Y e llo w - g r e e n
Y e llo w
Y e l lo w - o r a n g e O r a n g e
R e d - o r a n g e
R e d

Color TheorySOLO 1931
CIE 1931 color space
In the 1920's, W. David Wright (Wright 1928) and John Guild (Guild 1931) independently
conducted a series of experiments on human sight which laid the foundation for the
specification of the CIE XYZ color space.
The experiments were conducted by using a circular split screen 2 degrees in size, which is the
angular size of the human fovea. On one side of the field a test color was projected and on the
other side, an observer-adjustable color was projected.
The adjustable color was a mixture of three primary colors, each with fixed chromaticity, but
with adjustable brightness.
The observer would alter the brightness of each of
the three primary beams until a match to the test
color was observed. Not all test colors could be
matched using this technique. When this was the
case, a variable amount of one of the primaries could
be added to the test color, and a match with the
remaining two primaries was carried out with the
variable color spot. For these cases, the amount of
the primary added to the test color was considered to
be a negative value. In this way, the entire range of
human color perception could be covered. When the
test colors were monochromatic, a plot could be
made of the amount of each primary used as a
function of the wavelength of the test color. These
three functions are called the color matching
functions for that particular experiment.

Although Wright and Guild's experiments were carried out using various primaries at various
intensities, and a number of different observers, all of their results were summarized by the
standardized CIE RGB color matching functions r (λ), g (λ) and b (λ), shown in the plot on the right
(CIE 1931). Note that r (λ) and g (λ) are zero at 435.8, r (λ) and b (λ) are zero at 546.1, and g (λ) and
b (λ) are zero at 700 nm. These color matching functions are the amounts of three standard
monochromatic primaries needed to match the monochromatic test primary at the wavelength shown
on the horizontal scale. The three monochromatic primaries are at standardized wavelengths of 700
nm (red), 546.1 nm (green) and 435.8 nm (blue). The last two wavelengths were chosen because they
are easily reproducible monochromatic lines of a mercury vapor Gamut of the CIE RGB primaries
and location of primaries on the CIE 1931 xy chromaticity diagram. CIE 1931 color space. The 700
nm wavelength, which in 1931 was difficult to reproduce as a monochromatic beam, was chosen
because it is at the peak of the eye's red response, and therefore small errors in wavelength of this
primary would have little effect on the results.
The color matching functions and primaries were settled upon by
a CIE special commission after considerable deliberation
(Fairman 1997). The cutoffs at the short- and long-wavelength
side of the diagram are chosen somewhat arbitrarily; the human
eye can actually see light with wavelengths up to about 810 nm,
but with a sensitivity that is many thousand times lower than for
green light. These color matching functions define what is known
As the "1931 CIE standard observer". Note that rather than
specify the brightness o f each primary, the curves are normalized
to have constant area beneath them. This area is fixed to a
particular
value by specifying that g (λ) = V (λ) where V(λ) is the photonic

In 1853, Grassmann published a theory of how colors mix; it and its
three color laws are still taught, as Grassmann's law. Grassman's
work on this subject was inconsistent with that of Helmholtz.
Grassmann's Law in Optics
Hermann Günther
Grassmann
(1809–,1877)
In optics, Grassmann's law is an empirical result about human
color perception: that chromatic sensation can be described in
terms of an effective stimulus consisting of linear combinations
of different light colors.
( ) ( )
( ) ( )
( ) ( )∫
∫
∫
∞
∞
∞
=
=
=
0
0
0
λλλ
λλλ
λλλ
dbIB
dgIG
drIR
Grassmann's law can be expressed in general form by stating that for a given
color with a spectral power distribution I(λ) the RGB coordinates are given by:
Red requires some
negative values for
the function

52
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
(CIE) in 1931
The human eye has photoreceptors (called cone cells) for medium- and high-brightness color vision,
with sensitivity peaks in short (S, 420–440 nm), middle (M, 530–540 nm), and long (L, 560–580 nm)
wavelengths (there is also the low-brightness monochromatic "night-vision" receptor, called rod cell,
with peak sensitivity at 490-495 nm). Thus, in principle, three parameters describe a color sensation. The
tristimulus values of a color are the amounts of three primary colors in a three-component additive color
model needed to match that test color. The tristimulus values are most often given in the CIE 1931 color
space, in which they are denoted X, Y, and Z.
Any specific method for associating tristimulus values with each color is called a color space. CIE XYZ,
one of many such spaces, is a commonly used standard, and serves as the basis from which many other
color spaces are defined.
Tristimulus values
In the CIE XYZ color space, the tristimulus values are not the S, M, and L responses of
the human eye, but rather a set of tristimulus values called X, Y, and Z, which are
roughly red, green and blue, respectively. (Note that the X,Y,Z values are not physically
observed red, green, blue colors. Rather, they may be thought of as 'derived' parameters
from the red, green, blue colors.) Two light sources, made up of different mixtures of
various wavelengths, may appear to be the same color; this effect is called metamerism.
Two light sources have the same apparent color to an observer when they have the same
tristimulus values, no matter what spectral distributions of light were used to produce
them.
The CIE standard observer

53
CIE_1931_XYZ_Color_Matching_Functions.svg
)SVG file, nominally 446 × 271 pixels, file size: 54 KB(
CIE1931xy_blank.svg
The CIE has defined a set of three color-matching functions
called , , and , which can be thought of as the
CIE XYZ tristimulus values X, Y, and Z.,
( ) ( )
( ) ( )
( ) ( )∫
∫
∫
∞
∞
∞
=
=
=
0
0
0
λλλ
λλλ
λλλ
dzIZ
dyIY
dxIX
The tristimulus values for a color
with a spectral power distribution I
(λ) are given in terms of the standard
observer by
Color matching functions
The CIE xy chromaticity diagram and the
CIE xyY color space
Since the human eye has three types of color sensors that respond to
different ranges of wavelengths, a full plot of all visible colors is a
three-dimensional figure. However, the concept of color can be
divided into two parts: brightness and chromaticity. For example,
the color white is a bright color, while the color grey is considered to
be a less bright version of that same white. In other words, the
chromaticity of white and grey are the same while their brightness
differs.
The CIE XYZ color space was deliberately designed
so that the Y parameter was a measure of the
brightness or luminance of a color. The chromaticity
of a color was then specified by the two derived
parameters x and y, two of the three normalized
values which are functions of all three tristimulus
values X, Y, and Z:
( )
( )
( )ZYXZz
ZYXYy
ZYXXx
++=
++=
++=
/
/
/
The derived color space specified by x, y, and Y is known as the CIE xyY
color space and is widely used to specify colors in practice.

54
CIE_1931_XYZ_Color_Matching_Functions.svg
)SVG file, nominally 446 × 271 pixels, file size: 54 KB(
The CIE has defined a set of three color-matching functions
called , , and , which can be thought of as the
CIE XYZ tristimulus values X, Y, and Z.,
( ) ( )
( ) ( )
( ) ( )∫
∫
∫
∞
∞
∞
=
=
=
0
0
0
λλλ
λλλ
λλλ
dzIZ
dyIY
dxIX
The tristimulus values for a color
with a spectral power distribution I
(λ) are given in terms of the standard
observer by
Color matching functions
The CIE xy chromaticity diagram and the
CIE xyY color space
Since the human eye has three types of color sensors that respond to
different ranges of wavelengths, a full plot of all visible colors is a
three-dimensional figure. However, the concept of color can be
divided into two parts: brightness and chromaticity. For example,
the color white is a bright color, while the color grey is considered to
be a less bright version of that same white. In other words, the
chromaticity of white and grey are the same while their brightness
differs.
The CIE XYZ color space was deliberately designed
so that the Y parameter was a measure of the
brightness or luminance of a color. The chromaticity
of a color was then specified by the two derived
parameters x and y, two of the three normalized
values which are functions of all three tristimulus
values X, Y, and Z:
( )
( )
( )ZYXZz
ZYXYy
ZYXXx
++=
++=
++=
/
/
/
The derived color space specified by x, y, and Y is known as the CIE xyY
color space and is widely used to specify colors in practice.

1=++
++=
zyx
ZzYyXxColor


56
Because three dimensional objects can’t be illustrated very well a two dimensional representation
had to be found. The Y parameter of the so-called tristimulus values X, Y and Z is a measure of the
brightness. This helped to easily calculate the new chromaticity values x and y by the following rules:
( )
( )
( ) yxZYXZz
ZYXYy
ZYXXx
−−=++=⇒



++=
++=
1/
/
/
The corresponding chromaticity diagram is shown
in the right picture. The outer curved line is called
spectral locus and corresponds to the well known
color spectrum, shown with corresponding
wavelengths. The straight line on the lower part
between blue and red is called purple line. This line
relates to all colors which can only be mixed up by
blue and red which are not part of the color
spectrum.

The new color space would be chosen to have the following desirable properties:
1. The new color matching functions were to be everywhere
greater than or equal to zero. In 1931, computations were
done by hand or slide rule, and the specification of
positive values was a useful computational simplification.
2. The y(λ) color matching function would be exactly equal
to the photopic luminous efficiency function V(λ) for the
"CIE standard photopic observer" (CIE 1926). The
luminance function describes the variation of perceived
brightness with wavelength. The fact that the luminance
function could be constructed by a linear combination
of the RGB color matching functions was not guaranteed
by any means but might be expected to be nearly true due
to the nearlinear nature of human sight. Again, the main
reason for this requirement was computational
simplification.
Diagram in CIE rg chromaticity space
showing the construction of the
triangle specifying the CIE XYZ color
space. The triangle Cb-Cg-Cr is just
the xy=(0,0),(0,1),(1,0) triangle in CIE
xy chromaticity space. The line
connecting Cb and Cr is the alychne.
Notice that the spectral locus passes
through rg=(0,0) at 435.8 nm, through
rg=(0,1) at 546.1 nm and through
rg=(1,0) at 700 nm. Also, the equal
energy point (E) is at rg=xy=(1/3,1/3).
3. For the constant energy white point, it was required
that x = y = z = 1/3.

The new color space would be chosen to have the following desirable properties (continue):
4. By virtue of the definition of chromaticity and
the requirement of positive values of x and y,
it can be seen that the gamut of all colors will
lie inside the triangle [1,0], [0,0], [0,1]. It was
required that the gamut fill this space
practically completely
5. It was found that the z (λ) color matching function
could be set to zero above 650 nm while remaining
within the bounds of experimental error. For
computational simplicity, it was specified that this
would be so.

In geometrical terms, choosing the new color space amounts to choosing a
new triangle in rg chromaticity space.
In the figure on the right, the rg chromaticity coordinates are shown on
the two axes in black, along with the gamut of the 1931 standard observer.
Shown in red are the CIE xy chromaticity axes which were determined by
the above requirements. The requirement that the XYZ coordinates be
non-negative means that the triangle formed by Cr, Cg, Cb must
encompass the entire gamut of the standard observer. The line connecting
Cr and Cb is
fixed by the requirement that the function be equal to the luminance
function. This line is the line of zero
Diagram in CIE rg chromaticity space showing the construction of the
triangle specifying the CIE XYZ color space. The triangle Cb-Cg-Cr is just
the xy=(0,0),(0,1),(1,0) triangle in CIE xy chromaticity space. The line
connecting Cb and Cr is the alychne. Notice that the spectral locus passes
through rg=(0,0) at 435.8 nm, through rg=(0,1) at 546.1 nm and through
rg=(1,0) at 700 nm. Also, the equal energy point (E) is at rg=xy=(1/3,1/3).
CIE 1931 color space - Wikipedia, the free encyclopedia Page 5 of 8
http://en.wikipedia.org/wiki/CIE_color_space 9/18/2006 luminance, and is
called the alychne. The requirement that the function be zero below 650
nm means that the line connecting Cg and Cr must be tangent to the
gamut in the region of Kr. This defines the location of point Cr. The
requirement that the equal energy point be defined by x = y = 1/3 puts a
restriction on the line joining Cb and Cg, and finally, the requirement that
the gamut fill the space puts a second restriction on this line to be very
close to the gamut in the green region, which specifies the location of Cg
and Cb. The above described transformation is a linear transformation
from RGB space to XYZ space.

Color Blindeness, Confusion Lines and CIE 1931 color space
In 1855 J. C. Maxwell said: “Find two for a colorblind undistinguishable
colors. Mark them on the CIE diagram and draw a line through them. This
line will connect all colors which can’t be told apart by the colorblind
person. You then can find more lines and all of those lines are either
parallel or meet in a single point.”
A.König analyzed in 1892 the confusion lines and the so-called intersection
point (also called co-punctal point) on three persons affected by color
blindness.
In the year 1935 F. H. G. Pitt did some further research and found the
confusion lines and corresponding intersection points for protanopic and
deuteranopic persons.

Color Blindeness, Confusion Lines and CIE 1931 color space
D. Farnsworth (1955) and L. C. Thomson & W. D. Wright (1953) completed
the work by adding the results for tritanopic persons.
D-15 Farnsworth

Color Blindeness, Confusion Lines and CIE 1931 color space (continue – 1)
Many studies followed and up to today these confusion lines are the main source while
constructing tests on color blindness.
If you have a look at the diagram on the right side
you can see the confusion lines associated to
protanopic (red-blind) persons. The colors connected
by one line can’t be distinguished by a protanope. If
you would draw another line through the co-punctal
point (intersection point), all colors on that line would
look the same to a red-blind person too.
You can also see that there is a line going through a point called W. This is the so
called white-point. Of course white can be told apart from red, even by a colorblind.
But we have to take into account that the chromaticity diagram doesn’t include
lightness. This means all colors along a line need the correct lightness adjustment to
be undistinguishable by each other. Otherwise a colorblind can see a difference
evenso it would be only a difference in brightness and not a different color perception.

Color Blindeness, Confusion Lines and CIE 1931 color space (continue – 2)
The diagram of lines for deuteranopes (green-blind) looks quite the
same as for protanopes. Both types of color blindness share a
strong confusion on red and green colors, therefore the name red-
green color blindness
The last diagram looks totally different. The shown lines are
connecting undistinguishable colors for tritanopes (blue-blind).
Because the intersection point is at the blue end of the color
spectrum, the color perception is completely different to the ones
of red- or green-blind persons.
Confusion Lines – Deuteranopia
Confusion Lines – Tritanopia
When you have a close look at all three diagrams you can also see,
that the count of confusion lines differs. This is due to the
following fact: Each line shows the smallest difference between
distinguishable colors. This means not only the colors on one line,
but all the colors between two lines are undistinguishable by
persons affected by a certain type of color blindness
You can also see, that the lines are not exactly the same.
Especially the intersection point is outside the range of the
visible colors.

Color Theory
Color Blindeness
Normal Color Vision Red-Blind/Protanopia Green-Blind/Deuteranopia
Blue-Blind/Tritanopia
Blue-Weak/Tritanomaly
Red-Weak/Protanomaly Green-Weak/Deuteranomaly
Monochromacy/Achromatopsia Blue Cone Monochromacy
SOLO

Color TheorySOLO
Color Blindeness
People with normal color vision are called “Trichomats”
because they require three primates to match any arbitrary
sample. The Trichromatic Eye has three cone types, each
containing a photopigment which responds to a restricted range
of wavelengths.
There are several types of Color Deficiency due to Cone
Abnormalities.
In addition, the elderly see colors differently, but are not color
blind in the usual sense of the term. Finally, brain damage can
create a very rare condition called Achromatopsia.

Color TheorySOLO
Color Blindeness

Color TheorySOLO
Color Blindeness
Types of colour vision
deficiency
Males Females
Overall ~ 8 % ~ 5%
Anomalous trichromasy
protanomaly 1%< / FONT> 0.01%
deutanomaly 5% 0.4%
tritanomaly rare rare
Dichromasy
protanopia 1% 0.01%
deuteranopia 1.5% 0.01%
tritanopia 0.008% 0.008%
Monochromasy
rod monochromasy rare rare
cone monochromasy rare rare
atypical monochromasy very rare very rare
Prevalence of congenital colour deficiencies

Color TheorySOLO
Color Blindeness
Anomalous Trichomats
There is a subpopulation of “Trichomats”, who still requires three primaries
to match a sample, but whose matches are abnormal because they use one
primary far more than would be expected.
While having all three cone types, one cone type is rarer, has a reduced
amount of pigment, or has a pigment tuned to an unusual wavelength.
The “Anomalous Trichomats” can see all Hue Categories, so they are not
Color Blind in a real sense. But they may have difficulty in discriminating
colors, which a Normal would easy distinguish.

Color TheorySOLO
Color Blindeness
Dichromats
The second class of color abnormal is the Dichromat, a person who requires
only two primaries to match any sample. These people are missing one of
the three cones types.
Unlike color anomalous individuals, Dichromats are true Color Blinds in
the sense that there are some Hues which they cannot perceive. Lights which
would appear different to a Trichromatic will appear identical to a
Dichromatic, if they create the same activation ratio in their remaining Two
Cone Clases. Protanopes and Deuteranopes are Red-Green Color Blind and
see only Yellows and Blues. The Tritapone is analogously Blue-Yellow Color
Blind.
Dichromats have a Point on the Spectrum called the “Neutral Point” where
the light appears achromatic. The point is about the same for both classes,
495 nm for Prontanopes and 500 nm for Deuteranopes, wavelengths which
would appear slightly bluish Green to Normal.

Color TheorySOLO
Color Blindeness
Monochromats
Monochromats can match any light with a single primary. They
generally have no Cones and make all matches using Rods. They
are very rare, 1 in 10,000,000. With only a single receptor type,
they can have no Color Vision and are truly Color Blind because
they distinguish only Brightness Levels. Their vision is so
generally poor that the color section for visual design is the least
of their problems.

Color TheorySOLO
Generic Color Models
RGB uses additive color mixing, because it describes what
kind of light needs to be emitted to produce a given color. Light
is added together to create form from out of the darkness. RGB
stores individual values for red, green and blue. RGBA is RGB
with an additional channel, alpha, to indicate transparency.
Common color spaces based on the RGB model include RGB,
Adobe RGB and Adobe Wide Gamut RGB.
CMYK uses subtractive color mixing used in the printing
process, because it describes what kind of inks need to be applied
so the light reflected from the substrate and through the inks
produces a given color. One starts with a white substrate (canvas,
page, etc), and uses ink to subtract color from white to create an
image. CMYK stores ink values for cyan, magenta, yellow and
black. There are many CMYK color spaces for different sets of
inks, substrates, and press characteristics (which change the dot
gain or transfer function for each ink and thus change the
appearance).
YIQ was formerly used in NTSC (North America, Japan and elsewhere) television broadcasts for historical
reasons. This system stores a luminance value with two chrominance values, corresponding approximately to
the amounts of blue and red in the color. It is similar to the YUV scheme used in most video capture systems
and in PAL (Australia, Europe, except France, which uses SECAM) television, except that the YIQ color
space is rotated 33° with respect to the YUV color space. The YDbDr scheme used by SECAM television is
rotated in another way

Color TheorySOLO
Generic Color Models (continue)
YPbPr is a scaled version of YUV. It is most commonly seen in its digital form, YCbCr, used
widely in video and image compression schemes such as MPEG and JPEG
xvYCC is a new international digital video color space standard published by the IEC (IEC
61966-2-4). It is based on the ITU BT.601 and BT.709 standards but extends the gamut
beyond the R/G/B primaries specified in those standards.
HSV (hue, saturation, value), also known as HSB (hue, saturation, brightness) is often used
by artists because it is often more natural to think about a color in terms of hue and saturation
than in terms of additive or subtractive color components. HSV is a transformation of an
RGB color space, and its components and colorimetry are relative to the RGB color space
from which it was derived.
HSL (hue, saturation, lightness/luminance), also known as HLS or HSI (hue, saturation,
intensity) is quite similar to HSV, with "lightness" replacing "brightness". The difference is that
the brightness of a pure color is equal to the brightness of white, while the lightness of a pure
color is equal to the lightness of a medium gray.

Color TheorySOLO
Generic Color Models (Yuv)
Yuv and YCrCb: Digital Video
• Initially, for PAL analog video, it is now also used in CCIR 601 standard for Digital Video.
• Y (luminance) is the CIE Y primary, related to R, G, B by:
BGRY 11.0587.0299.0 ++=
• Chrominance is defined as the difference between a color and a reference white at the same
luminance. It can be represented by u and v – the color differences
YRvYBu −=−= ;
• YCrCb is a scaled and shifted version of Yuv and used in JPEG and MPEG (all components
are positive)
( ) ( ) 5.0402.1/;5.0772.1/ +−=+−= YRCrYBCb

Color TheorySOLO
Generic Color Models (YUV)
Color Space YUV
• Used for video encoding for some standards such as NTSC, PAL, SECAM.
• Axes:
( ) ( )
( ) ( )299.01/615.0
114.01/436.0
114.0587.0299.0
−−=
−−=
++=
YRV
YBU
BGRYConversion from RGB:
In Matrix form




















−−
−−=










B
G
R
V
U
Y
10001.051499.0615.0
436.028886.014713.0
114.0587.0299.0
Y: Luma
U: Blue Chroma
V: Red Chroma




















−−=










V
U
Y
B
G
R
003211.21
58060.039465.01
13983.101

Color TheorySOLO
Generic Color Models
Color Space YCbCr & YPbPr
• Used for video encoding for digital video encoding, digital camera.
• Axes:
( ) ( )
( )
( )YRCr
YBCb
GBGGRY
−=
−=
−++−=
713.0
564.0
114.0299.0Conversion from RGB:
In Matrix form




















−−
−−=










B
G
R
Cr
Cb
Y
081282.0418531.0499813.0
064296.0232932.0168636.0
114.0587.0299.0
Y: Luma
Cb: Blue Chroma
Cr: Red Chroma

Color TheorySOLO
Generic Color Models (YIQ)
Color Space YIQ
• Used for video encoding for some standards such as NTSC.
• Axes:
• I – Q channels are rotated from the U – V channels by 33º in YUV
Conversion from RGB




















−
−−=










B
G
R
Q
I
Y
311135.0522591.0211456.0
321263.0274453.0595716.0
114.0587.0299.0
Y: Luma
I: Blue Chroma
Q: Red Chroma
The Y component represents the luma information, and is the only component used by
black-and-white television receivers. I and Q represent the chrominance information
The YIQ system is intended to take advantage of human color-response characteristics. The eye is
more sensitive to changes in the orange-blue (I) range than in the purple-green range (Q) —
therefore less bandwidth is required for Q than for I. Broadcast NTSC limits I to 1.3 MHz and Q
to 0.4 MHz. I and Q are frequency interleaved into the 4 MHz Y signal, which keeps the
bandwidth of the overall signal down to 4.2 MHz. In YUV systems, since U and V both contain
information in the orange-blue range, both components must be given the same amount of
bandwidth as I to achieve similar color fidelity.


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
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
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
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
−
−−=

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







Q
I
Y
B
G
R
706.11070.11
6474.02721.01
6210.09563.01

Color TheorySOLO
Generic Color Models (CMYK)
Color Space CMYK
The CMYK color model, referred to as process color or four color, is a subtractive
color model, used in color printing, also used to describe the printing process itself.
CMYK refers to the four inks used in most color printing: cyan, magenta, yellow,
and key black. Though it varies by print house, press operator, press manufacturer
and press run, ink is typically applied in the order of the abbreviation.
Cyan, magenta, yellow, and
key (black).
Layers of simulated glass
show how semi-transparent
layers of color combine on
paper into spectrum of CMY
colors
Conversion from RGB
( )
( ) ( )
( )
( )YMCK
CbYY
CrCbYM
CrYC
,,min
1287718.1255
1287142.01283441.0255
1284021.1255
=
−−−=
−+−+−=
−−−=

Color TheorySOLO
Generic Color Models (CMYK)
Color Space CMYK
CMYK refers to the four inks used in most color printing: cyan, magenta, yellow,
and key black CMY(K).
A subtractive color model
Dye Color Absorbs Reflects
Magenta Green Blue and Red
Yelow Blue Red and Green
Cyan Red Blue and Green
Black all none

Color TheorySOLO
Generic Color Models (HSL and HSV)
HSL and HSV are two related representations of points in an RGB color model that
attempt to describe perceptual color relationships more accurately than RGB, while
remaining computationally simple. HSL stands for Hue, Saturation and Lightness,
while HSV stands for Hue, Saturation and Value
Comparison of the HSL (left) and HSV (right) color models
An HSV color wheel (left) allows the user to quickly select a
multitude of colors. The conical representation (right) of the HSV
model is well-suited to visualizing the entire HSV color space as a
single object. Notice that the triangle in the left image corresponds to
one face of the cone cross section in the right image.
Value is the maximum value of the R, G and B.
Saturation is the difference between the
maximal and minimal of the R, G and B.
Hue is a function of the color of the maximal
of R, G and B, adjusted by the other two.

Color TheorySOLO
Conversion from RGB to HSL
Let r, g, b ∈ [0,1] be the red, green, and blue coordinates, respectively, of a color in
RGB space.
max = max (r,g,b) , min = min (r,g,b)
s,l ∈ [0,1]
h∈ [0,360º]
HSL arranged as a double-cone

Color TheorySOLO
Generic Color Models (HSL and HSV
Conversion from RGB to HSV
An HSV color wheel (left) allows the user to quickly select a
multitude of colors. The conical representation (right) of the HSV
model is well-suited to visualizing the entire HSV color space as a
single object. Notice that the triangle in the left image corresponds to
one face of the cone cross section in the right image.
Let r, g, b ∈ [0,1] be the red, green, and blue coordinates, respectively, of a color in
RGB space.
max = max (r,g,b) , min = min (r,g,b)
s,v∈ [0,1]
h∈ [0,360º]

Color TheorySOLO
Generic Color Models (HSL and HSV
Conversion from HSL to RGB
Given a color defined by (h, s, l) values in HSL space, with h in the semi-open interval [0, 360),
indicating the angle, in degrees of the hue, and with s and l in the range [0, 1], representing the
saturation and lightness, respectively, a corresponding (r, g, b) triplet in RGB space, with r, g, and b
also in range [0, 1], and corresponding to red, green, and blue, respectively, can be computed as
follows:
First, if s = 0, then the resulting color is achromatic, or gray. In this special case, r, g, and b all equal l.
Note that the value of h is ignored, and may be undefined in this situation.
The following procedure can be used, even when s is zero:
The above operation is a modulo, so it can be simply
expressed as :

Color TheorySOLO
Conversion from HSV to RGB
Given a color defined by (h, s, v) values in HSV space, with h in the semi-open interval
[0, 360), and with s and v varying between 0 and 1, representing the saturation and
value, respectively, a corresponding (r, g, b) triplet in RGB space can be computed:
An illustration of the relationship between the “hue” of maximally
saturated colors in HSV and HSL with their corresponding RGB
coordinates

Color TheorySOLO
Generic Color Models (continue)
Run This
The GIMP supports several methods
of picking colors within the HSV
color model, including the color
wheel and a colored square with a
hue slider
GIMP (The GNU Image Manipulation
Program) is a free software raster
graphics editor. It is primarily
employed as an image retouching and
editing tool,[3]
in addition to offering
freeform drawing and retouching
tools, GIMP can accomplish essential
image workflow steps such as resizing,
editing, and cropping photos,
combining multiple images, and
converting between different image
formats. GIMP can also be used to
create basic animated images in the
GIF format. At present GIMP is
entirely suitable for amateur or
professional work with images
intended for viewing on monitors and
printing on inkjet printers; GIMP does
not yet offer the CMYK separation and
color management functionality which
is essential for prepress work.
Software support

Color TheorySOLO
Since our vision system uses three different
sensors to selectively detect the visual
spectrum, the color space they define is
inherently three dimensional. We can best
visualize this three dimensional color space as
a cube. One corner represents zero excitation
for all three sensors or the color we call black.
There is a sensor vector along each of the
three edges which leave this zero excitation
corner. These vectors represent the extent of
the stimulus for the Rho, Gamma and Beta
sensors. This cube has white at the corner
directly opposite black. It has a primary color
(red, green or blue) in the corner opposite its
complimentary color (cyan, magenta or yellow
- the secondary colors). Here is the
visualization of the color space defined by the
Rho, Gamma and Beta sensor stimulus
vectors
The RGB Color Cube

Color TheorySOLO
There is a line connecting the black and white corners of the
cube. This is the line of neutral gradient or you might think of
it as the 21-step stepwedge.
Neutral Gradient Line
There are lines connecting each of the primary colors (RGB)
with their corresponding secondary colors (CMY). These are
the lines of primary-secondary gradient. These are the lines
along which we make color correction judgments for prints of
color images.
Primary-Seconday
Gradient Lines
There is a triangular plane connecting each of the primary
colors (RGB). Notice also that all the fully saturated colors
live on the surface of the cube.
Plane of the Primary Colors

Color TheorySOLO
Each of the primary and secondary colors have their own paths from black to
white. The RGB primaries move away from the black corner along three
separate paths. Whenever a vector moves along a corner of the cube, it is
changing in a single variable - in this case, the RGB primary itself. Once the
RGB primaries reach their fully saturated corn of the cube, new vectors move
diagonally across a cube side, toward the white corner. When a vector moves
diagonally across a cube side, it is changing in two variables. To move from any
one of the fully saturated primaries toward white, an equal amount of the other
two primaries are added. For example to move from the red corner to the white
corner, green and blue are added.
Plane of the Secondary
Colors
There is also a triangular plane connecting each of the secondary colors
(CMY). Notice that this plane crosses the neutral gradient line at a point
closer to white than black and that the plane of the primaries crosses at a
point closer to black than white. We generally expect secondary colors to
reproduce lighter than primary colors in black and white images. Unlike most
other visualizations of color, this one based upon sensor sensitivity vectors
meets our expectation. The color cube, while perhaps a little more complex to
visualize, is a very good model for gaining a better understanding of color.
Primary and Secondary
Gradient Vectors
Secondary colors move from black to white corners in the opposite way
from primary colors. The move from black to fully saturated as diagonals
on a cube surface (two variable changes). In moving from fully saturated
corners to the white corner, they travel along an edge (single variable
change).
The fully saturated outer edge of the CIE chart exists as path around the
outside surface of the color cube. Edge of Saturated Hues

Color TheorySOLO
The color cube defined by our color
sensitivity vectors applies equally well to many
of the systems we use to record color and to
reproduce color because they are also three
color systems. Below is an illustration of the 3
vector representation for an RGB value as
used with 24-bit color on a computer. The
RGB value of [102,140,166] represents
102/255 or 0.40 red, 140/255 or 0.55 green,
and 166/255 or 0.65 blue. Three component
color is easy to visualize as three vectors
describing a location within the color cube.
There is no equivalently intuitive description
of RGB values on a CIE color chart. The cube
is an over simplification, since this color space
is as non linear as Einstein's warped time and
space that it lives within. Still, the color cube
is quite a useful first order approximation
concept for understanding how we perceive
color.
The 216 color palette used by web
browsers to down color 24-bit images
for 8-bit video cards is a real world
realization of this color cube and
provides another good way to visualize
3 sensor color space - Web Browser
Color Space.

Color TheorySOLO
The Color Conversion Process
As shown in the illustration above the colors from the original scene had to be compressed throughput the
process and the number of colors available from the original to the printed image is dramatically reduced. The
color conversion process that takes place within an ICC (International Color Consortium ) workflow manages
this compression by re mapping colors to retain the look of the original, even though the color gamut may often
be compressed or reduced. The method used to remap colors from one device to another is critical to the success
of a Color Management System or CMS.

Color TheorySOLO
The Color Calibration Process

Color TheorySOLO
The two predominant hardware tools currently used to measure color and
profile monitors, scanners, printers and even LCD projectors are Colorimeters
and Spectrophotometers.
A Colorimeter is a device for measuring the quality of a color by comparison
with standard colors or combinations of colors.
A Spectrophotometer is an instrument for measuring or comparing the intensities
of the colors of the spectrum. It can be used to determine the colors of light a
pigment absorbs and transmits.

Color TheorySOLO
In general Colorimeters are used for calibrating monitors and can only record emissive light.
They are much less expensive than spectrophotometers and also less accurate.
Spectrophotometers on the other hand are generally much more expensive and more accurate
than colorimeters. Spectrophotometers are most often used to record reflective readings from
printed test targets. These targets are made up of colored patches of known values that are
printed with your printer and then measured. These measurements are used to create custom
profiles for a particular paper, printer and ink set. This profile characterizes the color
capabilities of your printer.
Colorimeters are all very similar in design and the way they function. Spectrophotometers on
the other hand come in a variety of styles and prices. Some read one patch at a time, others can
read strips automatically or manually and one will even read the entire target automatically. A
recent product offering from GretagMacbeth, the "Eye-One" will read both emissive and
reflective data. You can use this all in one device to calibrate your monitor and read reflective
print targets for creating custom printer profiles.

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References
Color Theory
Wyszecki, G., Stiles, W.,S., “Color Science – Concepts and Methods, Quantitative Data
and Formulas”, John Wiley & Sons, 1967
Rodney, A., “Color Management for Photographers – Hands on Techniques for
Photoshops Users”, Elsevier, 2005
ASTR 511, Majewski, Lecture Notes (Fall 2005)
Gal Ben-David, “Video Engineering Course”, October 2009
Westland, S., Ripamonti., C.,“Computational Color Science Using Matlab”, John
Wiley & Sons, 2004
White, R., “How Digital Photography Works”, Que, 2nd
Edition, 2007
Jacobson,R.,E., Ray, S.,F., Attridge, G.,G., Axford, N.,R., “The Manual of
Photography – Photographic and Digital Imaging”, Focal Press, 9th
Edition, 2000
Morović, J., “Color Gamut Mapping”, John Wiley & Sons, 2008

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References (continue - 1)
Color Theory
http://www.nndb.com/people/016/000095728/
http://en.wikipedia.org/wiki/Johann_Heinrich_Lambert
http://en.wikipedia.org/wiki/Ignaz_Schifferm%C3%BCller
http://en.wikipedia.org/wiki/Louis_Bertrand_Castel
http://www.medienkunstnetz.de/artist/louis-bertrand-castel/biography
http://www-history.mcs.st-and.ac.uk/~history/Biographies/Castel.html
http://www.lib.udel.edu/ud/spec/exhibits/recent/science.html
http://www.amastro2.org/at/ot/othcs.html
http://www.colorsystem.com/projekte/engl
http://www.handprint.com/HP/WCL/color6.html

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Color Theory
http://www-history.mcs.st-and.ac.uk/Projects/Johnson/Chapters/Ch4_2.html
http://en.wikipedia.org/wiki/Color_photography
http://en.wikipedia.org/wiki/Color_theory
http://www.infoplease.com/ce6/people/A0853151.html
http://physics.nad.ru/Physics/English/optics.htm
http://psychology.about.com/od/sensationandperception/f/trichrom.ht
mhttp://en.wikipedia.org/wiki/Theory_of_Colours
http://en.wikipedia.org/wiki/Michel_Eug%C3%A8ne_Chevreul
http://www.brown.edu/Courses/CG11/2005/Group161/ColorTheory.htm
http://en.wikipedia.org/wiki/Ogden_Rood
http://en.wikipedia.org/wiki/Ewald_Hering
http://en.wikipedia.org/wiki/Albert_Henry_Munsell
httphttp://www.danielgmurphy.com/physics/4_color/d_color_models.html

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Color Theory
http://www.bauhaus.de/english/bauhaus1919/unterricht/unterricht_klee.htm
http://en.wikipedia.org/wiki/Paul_Klee
http://en.wikipedia.org/wiki/Wilhelm_Ostwald
http://www.coloracademy.co.uk/ColorAcademy%202006/subjects/ostwald/ostwald.htm
http://www.colblindor.com/2006/03/15/color-blindness-test-by-dr-shinobu-ishihara/
http://www.colorbasics.com/Munsell/
http://www.colourmed.com/tests.html
http://www.colormatters.com/colortheory.html
http://www.optics.arizona.edu/opti588/reading/CIE_color_space.pdf
http://www.fho-emden.de/~hoffmann/ciexyz29082000.pdf
http://en.wikipedia.org/wiki/CIE_1931
http://en.wikipedia.org/wiki/Grassmann's_law_(optics)
http://en.wikipedia.org/wiki/Hermann_Grassmann
http://webvision.med.utah.edu/
http://www.colblindor.com/coblis-color-blindness-simulator/
http://en.wikipedia.org/wiki/Color_space

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Color Theory
http://en.wikipedia.org/wiki/YUV
http://en.wikipedia.org/wiki/YIQ
http://en.wikipedia.org/wiki/HSL_and_HSV
http://en.wikipedia.org/wiki/GIMP
http://dx.sheridan.com/advisor/cmyk_color.html
http://photo.net/learn/optics/edscott/vis00020.htm
http://hyperphysics.phy-astr.gsu.edu/hbase/vision/colmeascon.html#c1
http://www.booksmartstudio.com/color_tutorial/colortools.html

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Technion
Israeli Institute of Technology
1964 – 1968 BSc EE
1968 – 1971 MSc EE
Israeli Air Force
1970 – 1974
RAFAEL
Israeli Armament Development Authority
1974 – 2013
Stanford University
1983 – 1986 PhD AA

Color theory

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