EIZO Color Handbook

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Lovibond 1915

Wilson 1905

Lacouture 1890

Babbitt 1878

Runge 1810

Grassmann 1853

Field 1877

Rood 1879

Itten 1944

Forsius 1611

Gregoire 1820

Newton 1704

Bourges 1918

Birren 1934

Hering 1878

Munsell 1905

NCS-­SYSTEM 1979

Bezold 1874

Irozu-­Mondou 1876

Kupka 1910

Color Circles

Runge 1810

Jacobs 1923

Raskin 1825

Bacon 1866

Hayter 1830

Color Circles Kunihiko Sugiyama

Who invented color circles ?

Chevreul 1861

Wundt 1874

Ostwald 1917

Color circles are diagrams that graphically express the concept of color.

Various styles have been used since ancient times, but circular and spherical diagrams are the most common.

The first step is to consider the simple question: “Why is color expressed using geometric conceptual schemes such as circular diagrams?”

When arranged side by side, we see 3,000 years of color culture history.

Hübl 1904

Author unknown 1708

Goethe 1810

Ziegler 1850

© DWH Co., LTD.

Bezold 1876

Herschel 1817

Itten 1944

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introduction

The origins of the sense of color

Looking at the large number of color system charts published in books on chromatics makes one wonder why so many are circular, and which individual might have devised the first color circles.

The beginnings with eight colors

This topic is touched on in the 2004 Japanese language edition of this publication.

This time, we will use the results of that analysis to study the key color circles in chronological order.

H

RY

D

O T

FIRE

EARTH

G

ET

Fig. 1: Diagram of a four-element, fourproperty diagram that spread from Greece to Arabia. The elementary colors are red, blue, yellow, and green.

O

W

LD

AIR

Aristotle B.C.384–322, Greece

WATER

Fig. 2: Eight-color ink well, from Color & Human Response by Faber Birren published in 1978.

How did people in ancient times conceive “color”? This is a question that has fascinated me for a long time. The article “The people that deciphered the rainbow” in the previous issue of this handbook was related to this fascination of mine. A look at the book entitled ClassiColor: Farven I Antik Skulptur allows one to see how ancient artists and craftsmen used the color palette.

According to American color researcher Faber Birren (1900-­1988), the palettes used by artists in the 4,000 years from ancient times up until the Renaissance consisted of only eight primary colors. Of course, far more colors are seen in the natural world, and this does not mean that ancient people were not able to see a wide range of colors. But it is believed that there was no need to distinguish between the wide range of colors as today, and only a few colors had significant meaning. We see similar observations in the work of French color researcher Michel Pastoureau.

British naturalist and geographer Alfred Russel Wallace (1823-­1913) conceived the theory of evolution before Charles Darwin, and wrote his ideas in a letter to Darwin. This prompted Darwin to rush his theory of evolution into publication to

avoid being scooped, resulting in Wallace sometimes being referred to as the “man eclipsed by Darwin.”

One of his works, Tropical Nature, and Other Essays (1878) , includes some interesting observations on the origins of the sense of color as a naturalist and biologist. While the passage is quite long, it is worth quoting here. “…It is quite possible that at first, green and blue were the only kinds of light-­vibrations which could be perceived at all. When the need for differentiation of colour arose, rays of greater and of smaller wave -­lengths would necessarily be made use of to excite the new sensations required;; and we can thus understand why green and blue form the central portion of the visible spectrum, and are the colours which are most agreeable to us in large surfaces;; while at its two extremities we find yellow, red and violet-­colours we best appreciate in smaller masses, and when contrasted with the other two, or with natural tints. We have here probably the foundations of a natural theory of harmonious colouring, derived from the order in which our colour-­ sensations have arisen and the nature of the emotions with which the several tints have been always associated.”

And also quoting from Zur E n t w i c k e l u n g s -­ g e s c h i c h t e d e r Menschheit (1871) by Lazarus Geiger regarding the development of a

sense of color in ancient times: “ The colour of grass and foliage is never alluded to as a beauty in the Vedas or the Zendavesta, though these productions are continually extolled for other properties. Blue is described by terms denoting sometimes green, sometimes black, showing that it was hardily recognized as a distinct colour. The colour of the sky is never mentioned in the Bible, the Vedas, the Homeric poems, or even in the Koran. The first distinct allusion to it known to Geiger is in an Arabic work of the ninth century. …Aristotle names three colours in the rainbow̶ red, yellow and green. Two centuries earlier Xenophanes had described the rainbow as purple, reddish, and yellow. The Pythagoreans admitted four primary colours̶white, black, red, and yellow; the Chinese the same, with the addition of green.”

These suggest that a wide range of colors was in used in ancient t i m e s , b u t barely describ ed in writing. While there may have been fewer names for the modern-­day primary colors, historical works such as On Colors by Aristotle and The Treatise on Color by Goethe indicate that many color names were in use GPS ¿PSB BOE GBVOB

Color Circles

Research into color starting with Aristotle

different colors (white, yellow, purple, green, blue, gray, and black), just as there

5IF ¾STU SFDPSEFE JO EFQUI TUVEJFT into color in human history were made by Aristotle and his students (s u c h a s T h e o p h r a s t u s) . A r i s t o t l e ’s theories on color and the visual TFOTF DPOUJOVFE UP JO¿VFODF TUVEJFT of color into the 19th century. It is wor thwhile to examine them in detail before discussing color circles.

Aristotle’s studies of light and color are discussed in his works D e A n i m a (O n t he S o u l), S e n s e a n d S e n s i b il i a , O n C o l o r s, a n d Meteorology. According to Aristotle, color is somet hing visible in light, and color is not normally v i sible i f l ig ht i s n o t p r e s e nt .

L i g ht p r op a g a t e s t h r o u g h t h e medium of air, an idea related to the Aristotlean theor y of visual senses. The explanation of where color comes from is a speculative explanation, and is esoteric enough to make even scholars give up in despair.

To summarize, color is explained a s e x i s t i n g on t h e b o u n d a r ie s (surfaces) of objects. The question of how many colors exist is discussed in On Colors, in which Aristotle says that colors range bet ween black and white, and that there are seven

White

Yellow

Red

Purple

are seven different types of flavor, with other colors being mixtures of these seven. This concept was known as the mixture of light and darkness theory. Elsewhere Aristotle writes that gray is an intermediate color between black and white, and while arranging the white-gray-­ black axis vertically would form a color solid, the explanation was not developed quite that far.

A ristot le’s color t heories a re written mainly in On the Soul. Let us now move on to see how Aristotle’s c o l o r t h e o r i e s s u b -­ s e q u e n t l y developed in the world.

The theory of visual perception originating in Ancient Greece is an essential part of the explanation of color. Plato used the concept of “line of sight” to explain how we see shapes and colors. Aristotle, however, postulated a reverse theory in which objects and colors are seen because the form of a color image (color species) like a cicada’s abandoned husk enters the eye from the object re duc e d to a v isua l p erc ept ion pyramid shape with the eye at its apex. Common concepts in ancient color t heories included ones in which light was a transparent color, and that what we see are shapes with color. But these explanations

Green

Blue

Black

included numerous contradictions.

Aristotle’s color theories were refined and reassessed by the 11th century Arabian scientist Alhazen, forming the basis of research on the structure of the eye and visual perception theories resembling those used to this day. These are covered the Book of Optics. Little remains from the Middle Ages, but in the 14th century, Aristotle’s visual perception theories were expanded in Opus Majus by Roger Bacon, and perspectivists such as Nicole Oresme.

Optics is the study of light, and the foundations of color research that subsequently took off from the 16th to 18th centuries with the completion of principles of realistic painting were derived from studies dating from the 11th to 14th centuries.

Fig. 4: ClassiColor Farven I Antic Skulptur. Indicates that ancient buildings and sculptures were colored.

This catalog contains significant evidence to support this.

Fig. 3: Aristotle’s seven basic colors. Gray is subsumed under black.

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Mixture of light and darkness theory Aristotle’s explanations of color included the explanation that the myriad of colors consisted of a mixture of light and darkness.

In his work Meteorology, Aristotle explains that “lines of sight became weaker when reflected, with dark objects becoming darker, and, white objects becoming blacker. He also described how the color (white) of lines of sight became redder when stronger, greener when slightly weaker, and bluer when increasingly weaker.” While color is widely discussed in many of Aristotle’s works, these are not scientific theories, and minor disparities are noticeable even within his works. The quote above highlighted in blue can therefore be described as a common concept with the mixture of light and darkness theory. So how then does the mixture of light and darkness theory differ from the transformation theory which states that white light is pure light and all colors such as red, blue, and yellow transform according to the degree of darkness intermixe d? T he trans format ion the or y applies not just to color, so problems arise when we try to collate it directly with the mixture of light and darkness theory. The definition can probably be virtually matched bylimiting it to “color transformation theory.”

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Who invented the color circle?

The idea of arranging colors in a circle

Aguilonius 1567–1617, Belgium

Robert Fludd 1574–1637, United Kingdom

Francis Glisson 1597?–1677, United Kingdom

Athanasius Kircher 1601–1680, Germany

Fig. 5: The upper wind rose was taken from Aristotle’s Meteorology printed in 1519. The lower wind rose is from Cardano’s Opera Omnia (1663).

The origins of color circles lie in wheels such as wind roses.

Note 1: Monochord means “single” in Greek, and more specifically refers to a string instrument with a single string in accordance with canonic stipulations.

The ratio of the string can be varied by moving the bridge along the string.

The first color circle Here we will consider which individual first invented what we today refer to as color circles and hue circles.

It is difficult to ascertain whether early color circles applied to artists’ paint colors or to light, and this ambiguity persisted even after Newton had explained the characteristics of light. Here we will look at and compare a wide range of color concept diagrams and items used in design teaching, including circular and spherical systems, not limited to what are referred to as color systems in chromatics.

From ancient times up until the Middle Ages, circular diagrams were produced in great quantities, including those for horoscopes and wind rose diagrams (Fig. 5), and for annular diagrams for calendars. So it is likely that colored versions of these tools formed the basis for the idea of color circles. Early color circles can also be seen in works related to alchemy, which had continued to attract attention since ancient times.

Also, early medicine was based on diagnosing the color of bile and urine, which required foundations for the order in which to arrange colors, such as urine color circles.

It was not until the 18th century that color circles became widespread.

Color circles in this period began to develop from the ancient concept diagrams into practical tools for use in color assortment and color

matching in areas such as the textile industry.

Monochord diagram T he A ncient Gre ek mat he -­ matician Pythagoras devised the harmonics of sound. The harmonic relationship of the seven tones of the do, re, mi, fa, sol, la, ti chromatic scale was expressed until the Middle Ages using a variety of different diag ra ms. T his wa s refer red to as the monochord theor y in the Middle Ages, and the color diagrams conceived by Aguilonius, Glisson, and Kircher, were clearly monochord (Note 1) style diagrams from classical music adapted for use with color.

These diagrams had black and white arranged at the ends, with other colors arranged in between, clearly derived from Aristotle’s color theory.

Looking at these diagrams, it does not appear that Aristotle’s color theory targeted a color circle or color solid.

Color circles in medicine Rober t Fludd wa s a Brit ish physician, a member of the secretive Rosicrucian society, and a proponent of Hermes Trismegistus.

His work Medicina Cathorca (Frankfurt, 1629) includes a color ring diagram (Fig. 7). The 2nd century thinker and proponent of gnostic Basilidas of Alexandria is said to have compared the seeds of the world to peacock

eggs laid inside the seven colors of the regions of the earth. The seven colors on Fludd’s color ring were red, orange, yellow, white, black, blue, and green (Fig. 7), clearly ref lect ing gnosis, ba sed on t he four main elements of Aristotle.

Black and white represented both extremes of darkness and light, while red lay between. Orange and yellow were arranged between red and white, and green and blue were arranged between red and black.

Fludd also worked on measuring the color of urine and invented a urine measuring device. He believed that color was not simply symbolic, but an important diagnostic tool in medicine.

The oldest color circle printed in color The color circle by an unknown author and printed in the Nether-­ lands is an illustration related to pastel tones. It was printed after Newton’s Opticks was published in 1704, and the 7-­segment diagram shown on the left-­hand side in Fig. 10 appears to have been influenced by this.

Color Circles

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Color Circles Shown in Diagrams- 1

Fig. 6: Aguilonius considered the relationship with Pythagorean rhythm while adhering to Aristotle’s theories.

Phase transforming this diagram suggests the color solid shown to the right.

Fig. 9: Color scale devised by Glisson (1597? – 1677, Britain), a physicist at Cambridge and royal advisor. Blue, red, and yellow were located between black and white at the ends, with the horizontal line forming a grayscale (1650).

Fig. 7: Fludd expressed the color perception of alchemy in his circular “Color wheel” diagram (1629).

Fig. 11: Color circles published by the printer Vandore in The Hague, in the Netherlands in 1708 (author unknown) with seven and twelve colors. These color circles are said to be the oldest color circles printed in color. From the initials C.B, it is conjectured that the author may have been Clause Boutet.

Fig. 10: Graphic representation of Aristotle’s theories produced by the learned visionary scientist Kircher.

He explained the Aristotlean variety of colors in chapter 2 of Ars Magna Lucis et Umbrae by modifying Aguilonius’s diagram.

Fig. 8: Color of urine: John of Cuba, Hortus Sanitatis 15th century urine color charts used by physicians in the Middle Ages to diagnose the color of urine expressed the sequence of colors from yellow to red as variations from white to black.

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Color Solid Idea How did Color Circles become color spheres?

Robert Grosseteste c.1168–1253, England

Leon Battista Alberti 1404–1472, Italy

Leonardo da Vinci 1452–1519, Italy

Robert Grosseteste’s understanding of light and color Robert Grosseteste was the first chancellor of Oxford University and the author of the treatise On the Rainbow around 1230, describing his unique understanding of color gained from translations of Aristotle’s works. “…There are seven colors close to white, no more and no fewer. These colors are created through transformations further away from white. … Similarly, there are seven colors close to black, and these rise from black to white until they meet with the colors descending from white. White has three properties: the amount of light, the brightness of light, and the pureness of the transparent body. One of the three will attenuate if two remain unchanged, creating three different

Aron Sigfrid Forsius ?–1637, Sweden

colors. … This is how seven colors in total are created from white.” (On the Rainbow, collection of Christian mystic works)

This description clearly brings t o m i n d t h e a r ra n ge m e n t o f a color solid. The choice of seven colors (the actual colors are not indicated) is based on Aristotle’s provisions, and probably led to the seven colors of the spectrum specified by Newton.

I would envisage “the amount of light, the brightness of light, and the pureness of the transparent body” as corresponding to hue, intensity, and saturation, but perhaps this is an excessive leap of imagination.

Leonardo da Vinci’s primary colors The leading Renaissance painter Leonardo da Vinci did not write much about chromatics, but he does mention color briefly in his A Treatise on Painting. According to da Vinci, there are six primary colors: white (light, sun), yellow (earth), green (water), blue (air), red ¾SF , and darkness (black). These six primary colors can be described as predecessors of the six fundamental colors of the NCS (Natural Color System) color order system used in the 20th century.

Alberti’s color solid

Fig. 12: A diagram illustrating the sketches drawn by Leonardo da Vinci.

One of the leading Renaissance architects, Leon Battista Alberti, wrote very briefly on topics related UP DPMPS JO UIF ¾STU QBSU PG IJT XPSL On Pictures (1436). “… The true colors

consist of just four primary colors.

These give birth to other kinds of DPMPST 3FE JT UIF DPMPS PG ¾SF MJHIU blue is the color of the atmosphere, water is green, and earth is brown (yellow) and gray. Other colors such as jasper and sulfur are mixtures of these colors. These four colors are thus parent colors, and combining them with darkness (black) and light (white) creates their color variations of their own…” This description brings to mind a double-­cone color solid, and also a three-­dimensional four-­element, four-­property diagram.

(See Fig. 14 and 15)

Mathematician Forsius’s color sphere idea was the first diagram Early in the 20th century, detailed sketches of a color sphere were discovered in a notebook belonging to the Swedish mathematician Aron Sigfrid Forsius. That notebook was written in 1611, which indicates an advanced level of completion for the early concept of the color sphere. (The sketch itself was not colored, h o w e v e r. ) Wh e r e a s t h e i d e a s o f Grosseteste and Alberti are purely conjectural, Forsius’s idea clearly envisaged an overall arrangement of color perceivable by humans. This can therefore, without doubt, be described as the world’s oldest color sphere (color solid).

Color Circles

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Color Circles Shown in Diagrams- 2 Wh

Wh

B

B

G R

R

G Y

Y

Blk

Blk

Wh

White

Fig. 14: (Avove) Expressing Leon Battista Alberti’s relationship between the four primary colors of red, blue, green, and yellow with black, gray, and white enables it to be three-dimensionally visualized in an arrangement as shown in the two figures above.

Wh

Fig. 16: Colors as envisaged by Forsius with four primary colors of red, yellow, green, and blue arranged on the equator line, and with a grayscale line as the vertical center axis from white (heaven) to black (earth).

Life colour — tree and wheat colour — chalk grey — pale blue Pale red — pale yellow — apple mould — verdigris — sky blue Red — yellow — grey — green — blue Purple — flame yellow — mouse grey — grass green — dark blue

２

１

１

２

３

４

５

６

３

７

Violet — black brown — black grey — black green — indigo ４

７

５

６

Black

Y

ASK RE G

OW

GE

ELL

W LO

AN

Blk

EY

PAL L YE

OR

Blk

WHITE

Fig. 17: English nomenclature for Fig. 16.

LUE

YB

SK

BLUE

RED

EG

EN

EEN

BLACK

RE

BR O W N VIO LET -BR OW N

REE

G

Fig. 15: (Left) It can also be visualized as the color solid shown below if treated as a sphere instead of a double cone.

-GR CK

between the seven colors and black and white.

(Above) An illustration showing this idea as a double cone.

PAL

PLE

R PU

BLA

Fig. 13: (Above) Robert Grosseteste’s relationship

N

Fig. 18: Forsius color circle viewed on the equator.

Fig. 19: English nomenclature for Fig. 18.

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Birth of the color circle

Was Newton’s color circle a chromaticity diagram?

Differences between light and paint clarified by explanation of light

Some 50 years after Forsius’s color solid idea, Cambridge University professor Isaac Newton conducted experiments exploring sunlight. He included his famous color circle in his work Opticks, published in 1704.

Newton described his color circle as transforming from the seven colors arranged around the circumference towards white in the center, with the intermediate colors determined by their specific positions. The small circle indicated a centroid of the arc divided into seven.

The seven colors of light (red, orange, yellow, green, blue, indigo, and violet) are arranged around the circumference, but all the colors of the spectrum are actually considered to be arranged around the circumference. (However,

Newton used the word spectrum, meaning “apparition,” in Latin, to describe the color band produced by triangular prisms.

Newton discovered that the seven colors contained in white light rays were diffracted differently to create the rainbow phenomenon.

Isaac Newton 1642–1726, England

Moses Harris 1731–1785, England

since this is a schematic diagram, these colors do not coincide with the actual spectrum

Fig. 20 : If inverted from left to right, this illustration entitled “Shadows and reflection” in Linear Perspective (1715) by Brook Taylor (1685 – 1731) virtually coincides with Newton’s color circle.

The two lines appear to verify Newton’s center of gravity laws.

Fig. 21: Musical scale diagram included in Descartes’ Compendium Musicae.

wavelength positions.) It may be that

Newton did not color his color circle because it represented the colors of light and not pigments.

Perhaps Newton’s color circle is frequently discussed due to the various techniques hidden within it.

One was the way in which Newton fitted his own color circle to the seven tones of the musical scale. This JT ¾SNMZ CFMJFWFE UP CF JO¿VFODFE CZ the illustration included by Descartes in his work Compendium Musicae.

When overlaid, the center angles for each color match almost perfectly.

Another point is that Newton describes the center of the color circle as white, so one should visualize the seven spectral colors arranged around the circumference transforming toward the center.

Moreover, when Newton writes that the color of a specific point within the circle can be determined using the center of gravity rule, it becomes possible to envisage this diagram as a circular chromaticity diagram.

The center of gravity rule is relatively easy to understand and can be considered an excellent way of describing unspecified colors without using the concept of vectors.

In his book The Artful Universe, physicist John D. Barrow includes a spherical interpretation as shown on the bottom left. No one else has made such a bold interpretation.

Two color circles by entomologist Moses Harris Some color circles are noted for their beauty. These include the two color circles that form part of the work Natural System of Colours published in 1766 by British ento-­ mologist and engraver Moses Harris.

This is a precious work in the field of chromatics, with only four copies known to exist. Schiffermüller, discussed in the next section, was also an entomologist.

Harris created two color circles entitled “Prismatic” (prismatic color circle with three primary colors red, yellow, and blue) and “Compound” (compound color circle with three primary colors orange, green, and purple) (see Fig. 24) . The prismatic

color circle on the bottom left is formed of 18 colors mixed from the three primary colors red, yellow, and blue. Despite using the term prismatic, Harris made the error of using the subtractive color mixtures red, yellow, and blue as the prismatic primary colors.

Harris’s forté was engraving, and he uses the density of black lines to represent the 20 intensity gradations for each color toward the center of the circle. The colors were added using watercolor, an impressive achievement in an age before dot color printing. It is no exaggeration to call these color circles, alongside those of Chevreul, the most beautiful known to exist.

Color Circles

Color Circles Shown in Diagrams- 3

Fig. 22: Newton used this diagram to illustrate how the colors of the spectrum produced white when mixed, but he also considered the correspondence between the seven colors and the seven musical tones.

Light G Y

or Blue le Purp R Dark

Fig. 23: Illustration from The Artful Universe (1995)

by John D. Barrow.

Fig. 24: (Three diagrams on right) Harris was a skilled engraver, increasing the number of engraved black lines to adjust the intensity, with three lines for level 4 and 12 for the innermost level 20. He illustrated a total of 660 colors (360 for the prism color circle and 300 for the compound color circle).

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Mystic color circles From late 18th to 19th century

Color circle devised by an entomologist Austrian entomologist Ignaz 4DIJøFSN MMFS QVCMJTIFE B CFBVUJGVM illustration containing the color circle shown to the left in his 1772 work Versuch eines Farbensystems.

An unusual feature of this color circle was the use of continuous gradations. The color circle consisted of a total of twelve colors, including the four primary colors of red, blue, green, and yellow, and eight other secondary colors, and the twelve colors were given unique names. The center of the circle contained the sun–the source of all color. The four illustrations with a rainbow theme clearly show a mixture of pigment and light colors.

Fig. 25: Ignaz Schiffermüller (1727- 1806, Austria)

Johann Wolfgang von Goethe 1749–1832, Germany

Phillip Otto Runge 1777–1810, Germany

Goethe’s color circle The literary figure Go ethe began studying chromatics in his 40s, devoting two-­thirds of his life to the study of chromatics. His three-­part work, Zur Farbenlehre (Theory of Colors) , was published in 1810, by coincidence the year in which Runge died. A proponent of Aristotle’s color theory, Goethe believed color existed between black and white. Goethe regarded color perception to be a psychotropic effect and conducted physiological experiments to invent a color circle for the six colors o ccurring in residual images. He explained this in terms of the two pure colors,

yellow (light) and blue (dark) under the concept of Steïgerung (elevation), developing this into a theory of color harmony (Fig. 27) . Go ethe QSPEVDFE UXP EJøFSFOU DPMPS DJSDMFT one a six-­color circle (Fig. 26) without Newton’s somewhat forced addition of indigo. This six-­color circle is a color circle made up of three pairs of complementary colors (red-­ green, purple-­yellow, blue-­orange) based on residual image colors. Produced with assistance from Friedrich Schiller, the other color circle (Fig. 28) consisted of crimson, orange, yellow, green, blue, and purple arranged around the circumference, with black at the center. The outermost ring is divided into choleric, sanguine, phlegmatic, and melancholic, with these temperaments each further divided into three.

Goethe’s color circle epitomizes his color theories, and the theories were positively inherited alongside with those of Itten and Klee of Bauhaus, as well as Runge, and incorporated in design teaching.

Readers interested in learning more are encouraged to read Goethe’s greatest work, Theor y of Colors, although tremendous patience is necessary due to its length.

Runge’s color sphere Runge was an artist who built the foundations for the German romantic painting style. He devoted his later years to the study of color.

Runge published his color theory

and color sphere diagram (Fig. 29) in his work Farbenkugel in 1810 before dying in the same year at the early age of 33. Runge’s color sphere was clearly modeled on the Earth. A color circle for pure colors lay at the Equator, with black placed at the South Pole and white at the North Pole and the axis connecting the two poles forming a grayscale. All mixed colors are thus present within the sphere.

Issues with the structure o f Ru n g e’s c o l o r s p h e r e w e r e highlighted a centur y later by Professor Ostwald (Wilhelm Ostwald) .

He understood that adding white or black to the colors on the equator of the sphere, shifting them toward the two poles, reduced the number of mutually differentiated colors, and that having gradations along the surface of the sphere was an error. He proposed that they should instead vary linearly. Nevertheless, this color sphere was praised by Johannes Itten and Paul Klee of Bauhaus in the 20th century, with Runge’s ideas being incorporated into standard teachings on color.

Ru n ge’s wo r k Fa r b e n k u g e l has b een reprinted and can b e downloaded in PDF format on the Internet, but is currently available only in German. I was able to view the original at the Goethe-­Museum in Düsseldorf.

Color Circles

15

Color Circles Shown in Diagrams- 4

Fig. 26: Symbolic use of color 6) Vereinung Rot

Orange

4) edler kontrast

Violett

3) Steigerung

2) Steigerung

Fig. 29: Runge’s color sphere. The diagram is a colored engraving.

Gelb

1) gemeiner Kontrast

Blau

reiner ursprünglicher K. Grün 5) Vereinung

Fig. 27

Fig. 28

Fig. 27: Steïgerung (elevation). Goethe used a color circle to explain his concept of “Steïgerung.”

Fig. 28: Color wheel illustrating the human temperaments, created with assistance from Schiller. It consisted of crimson, orange, yellow, green, blue, and purple arranged around the circumference with black at the center. The outermost ring is divided into choleric (autocrat, hero, adventurer), sanguine (good person, enthusiast, elegant person), phlegmatic (teacher, historian, orator), and melancholic (philosopher, scholar, monarch). The traits in parentheses are located in the middle.

Fig. 30: Diagram contained in Farbenkugel by Runge. It is a three-dimensional version of Goethe’s color circle.

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Color harmony and color solids The beginnings of practical color theories Michel-­Eugène Chevreul 1786–1889, France

Charles Henry 1859–1926, France

Fig. 31: Chevreul’s tone scale (for Blue).

Pure color is located midway.

Fig. 32: From Charles Henry’s La Lumiere, La Couleur, La Forme (1922).

Chevreul’s color system originating from the illusion of color French scientist and chromatic researcher Michel-­Eugène Chevreul devised a color system for color harmony, publishing this in his work The Principles of Harmony and Contrast of Colours in 1839. This work won high praise as a book on color theory encompassing all aspects of color, from painting and pigments to printing. His subsequent book The Principles of Harmony and Contrast of Colours, and Their Applications to the Arts, published in 1864 (diagrams printed in 1855) became a color theory manual for Impressionist painters at a time of significant changes in the art world. Chevreul’s color circle was printed using lithography and received the gold award at the Paris Expo held in 1855.

Not long after being appointed director of dyeing at the Royal Manufactory of Gobelins in France, C h e v re u l re c e i ve d c o m p l a i n t s concerning the poor quality of the colors, including blue, mauve, gray, brown, and black. His investigations into the problems marked the beginning of his serious studies into color. His research showed that the phenomenon did not involve problems with dyeing technology, but was attributable to the different ways in which a thread of a certain color appears when woven next to other colors, rather than viewed

alone. This was the phenomenon in which colors appear lighter when surrounded by dark colors and darker when surrounded by light colors, a fundamental aspect taught in the first stages of chromatics today.

He also identified the existence of a contrasting effect in the coloration for complementary color relationships. This was likely the first research in the world in which color arrangement was applied to industrial productivity.

Let us now examine Chevreul’s color solid, referring to the three-­ dimensional structure in Fig. 35.

The color solid is a hemisphere with white at the center of the base, pure colors arranged midway, and tones (ton) varying toward the circumference. Fig. 31 shows the 20 tone gradations from white to black.

Chevreul’s color solid is based on the three characteristics of hue, tone, and turbidity. Chevreul called the gradations toward the center axis turbidity (ton rabattu) . The turbidity of colors declines toward the base toward the center axis and increases in a conical arrangement. The center axis is achromatic color, from white at the lower end, through gray, to black at the top. The common image we have of color solids usually consists of pure colors arranged around the equator with white at the upper pole and black at the lower pole. Chevreul’s color solid, however, uses black for the exterior, with the base becoming white and individual hues arranged midway along the

hemisphere, making it difficult to visualize. For this reason, it is occasionally misinterpreted, even in academic publications.

Charles Henry’s color sphere Charles Henry was an assistant librarian at the Sorbonne, an assistant professor at the institute of higher education, and a mathematician and philosopher on esthetics who held the important position of director at a psycho-­physiological laboratory.

He included color reproductions of a color sphere (Fig. 32) in his works Cercle Chromatique (1889) and La Lumiere, La Couleur, La Forme (1922).

These works examine the relationship between color and musical scales from a mathematical perspective.

His works contain equations and graphs, giving them a somewhat daunting aspect, but the color sphere immediately betrays the influence of Chevreul.

Henry was in contact with numerous artists, including Georges Seurat and Paul Signac, and was a supporter of the theories of the new Impressionists.

Color Circles

17

Color Circles Shown in Diagrams- 5

Color solid diagram

Divided color circle diagram

Turbidity-0

Turbidity-1

Turbidity-2

Turbidity-3

Turbidity-4

Turbidity-5

Turbidity-6

Fig. 34: Chevreul (1861) Fig. 35: Chevreul’s three-dimensional color solid

Turbidity-7

Turbidity-8

Turbidity-9

Fig. 33: Ton rabattu from Chevreul’s Exposé d’un moyen de definer et de nommer les couleurs (1861).

(Fig. 33 and 34 are used with permission from Akira Kitabatake’s Key Works in Chromatics.)

Constant lightness plane

Constant turbidity plane

(d = 4, 16, 20)

(b = 0, 3, 6, 9)

Constant hue plane (h = 0, 6, 12, … 66)

Courtesy of Mitsuo Kobayashi (honorary professor, University of Electro-Communications)

18

Musical and color harmony System of light and pigment from the explanation of light

Fig. 36: Color scale

George Field 1777?–1854, England

Fig. 37: From Chromatics: or, An essay on the analogy and harmony of colours (1817).

Mystic Field’s color circle British dye researcher and pigment manufacturer George Field described his unique harmony theories in a number of books based on the results of developing pigments and dyes. Notable works include Chromatics (1817) , Chromatography (1835) , and Rudiments of the Painters (1850) . As well as being a scientist, he was a proponent of Aristotle’s color theories. Fig. 36 shows the illustration (not a color circle) included in Chromatics. This diagram is also used in the diagram showing the musical scale and color in Fig. 40. The arrangement of colors between black and white at either end reflects the Aristotelian perception of color. The numerous color illustrations included in his works also convey a sense of mysticism.

Field’s color circle naturally uses pigment color mixtures, with the three primary colors arranged like overlapping petals with the center containing achromatic black. The tertiary color within the petals is expressed as Dk. Perhaps the most interesting aspect is the quest for similarities between color and shape with a comparison of the three primary colors, red, yellow, and blue, to the musical scale do, mi, and so, and to the three primary figures of lines, angles, and curves. As with the secondary colors, when the secondary shapes (pyramid, cylinder, cone)

meet at the center of the sphere, the respective base area ratios approach the harmonic ratio (5:3:8) of the three primary colors derived by Field, suggesting a quest for a principle unifying color and shapes. No doubt this was inspired by Kepler’s attempts to derive the laws of planetary motion from inscribed platonic solids.

Field’s color harmony theory used an experimental device called a metrochrome, which he devised UP EF¾OF UIF DPMPS IBSNPOJFT PG UIF three primary colors of red, yellow, and blue as a compound ratio. The metrochrome featured three wedges engraved with a scale according thickness, as shown in Fig. 39. If three primary color solutions were added and overlaid to observe the transparent colors through the viewing glass, an achromatic color could be obtained for the ratio red 5 : ZFMMPX CMVF 5IJT SBUJP EF¾OFE the harmony color mixture as the area ratio. In other words, the ratio of 5:3:8 formed the harmony datum ratio. This was a ground-­breaking idea from the point of expressing color harmony quantitatively, but it was also criticized for this reason by the likes of Bezold, Brucke, and Rood, aside from criticism of the analogy to the musical scale.

The contributions of Field’s research into pigments and dyes in the area of industrial technology was highly acclaimed at the time, but appears less widely acknowledged in later color research.

Irozu-Mondou and its debt to Field’s color circle T h e M e i j i Re s t o r a t i o n i n Japan brought about tremendous changes in education. 1872 saw the publication of The Elementary Education Guide, based on practices from the West. The first textbook in Japan on color, Irozu-­Mondou, is JO¿VFODFE CZ UIF UIFPSJFT PG /FXUPO Field, and Chevreul, with Wilson’s diagram (Fig. 41) incorporated without modification. This diagram was printed using woodblock printing, with separate wood blocks for each color. Comparing the left and right diagrams on the right-­hand page shows that the Japanese diagram is identical to Field’s diagram, except for the circle of achromatic color in the center. The actual colors used in UIF QSJOUJOH DMFBSMZ EJøFS CVU UIJT JT due to the materials used in printing.

While color research in Japan began much later than in the West, this volume marks the clear start of color research in Japan.

Color Circles

Color Circles Shown in Diagrams- 6

Fig. 38: Field’s color circle (1841).

Fig. 39: Experimental color harmony metrochrome.

Fig. 41: Three primary colors and color mixing diagram in Irozu-Mondou (1876).

Fig. 40: Field’s color and sound comparative scale.

Fig. 42: Color diagram by Wilson (USA).

19

20

In search of applicable theory Building the foundations of modern chromatics Hermann Günther Grassmann 1809–1877, Germany

Hermann Ludwig Ferdinand von Helmholtz 1821–1894, Germany

Ogden Rood 1831–1902, USA

Grassmann’s color circle German mathematician Hermann Günther Grassmann is famous for Grassmann’s Law for color, which allows color to be expressed as a color space vector consisting of three -­ dimensional RGB co ordinates. Grassmann’s 1853 color circle (Fig. 43) moves the spectrum start and finish point to the 12 o’clock position, based on Newton’s color circle, and the boundary lines for Newton’s initial red and final violet are assumed to correspond to the Fraunhofer B and H lines. Symbols indicated on the Fraunhofer spectral diagram are included inside the circle verifying the positions of adjacent colors in detail. Grassmann contributed to the foundations of mo dern chromatics, his color circle analysis draws on a classical approach.

Helmholtz’s color circle Wilhelm Max Wundt 1832–1920, Germany

Karl Ewald Konstantin Hering 1834–1918, Germany

Hermann von Helmholtz, a German physiologist and physicist, made significant contributions in physiological optics and acoustic physiology. He develop ed and presented the theory relating to the three primary colors of light proposed some 50 years earlier by Thomas Young (the Young-­Helmholtz’s physiological trichromatic theory) , which made it possible to explain the colors of residual images and color blindness. The color circle in Fig. 44 shows a cone-­shaped color solid as

viewed from above. The line through purple likely means the color was not found in the spectrum.

Wundt’s color sphere Wilhelm Wundt, a German physiologist, philosopher, and psychologist, is often called the father of experiment psychology. Published in 1874, Wundt’s color sphere can be seen as a development of the classical Newtonian color circle. However, UIF DFOUFS BOHMFT EJøFS TJHOJ¾DBOUMZ from those of Newton, although it is unclear whether this is arbitrary or deliberate. The center of the sphere is, as expected, neutral gray.

Hering’s four-primarycolor color circle Focusing on color perception, Ewald Hering in 1878 proposed the opponent color theory, which sought to overturn the mainstream Young–Helmholtz theory. It did not win wide acceptance. According to the principles of mixed colors, yellow is created by combining red and green in the three RGB primary colors. However, Hering focused on observation results indicating that red and green hues could not be sensed simultaneously from yellow;; red and green hues could not be sensed when observing sp ecific colors;; and yellow and green hues could not be sensed simultaneously.

These observations prompted him to question the theory of three primary

colors. Hering’s theory assumed three fundamentally perceived opponent color pairs of red-­green, yellow-­blue, and black-­white. He also theorized that the retina included black/white, red/green, and yellow/blue receptors, speculating that these receptors underwent contrasting changes of “dissimilation” and “assimilation” due to light. Hering’s innovative color circle in Fig. 49 suggests that individual secondary colors can be extracted by mixing in the ratios of the lines a, b, c and a’, b’, c’ in Fig. 48.

T h e Yo u n g -­ H e l m h o l t z trichromatic theory and Hering’s opponent color theory are both considered valid today, based on the stage theory of color vision that the neural information processing involved in color perception depends on the stage of visual sensation.

Ogden Rood’s complementary color circle and harmony color circle Ogden Rood was an American physicist, professor at Columbia University, and an amateur painter.

Rood’s most important work is Modern Chromatics, published in 1879, in which he provides his famous color chart (Fig. 46), clearly illustrating the differences between the colors of pigment and light. His work was published in French in 1881, becoming the color bible of the neo-­impressionist painters at the time. Pissarro, Seurat, and Signac ↗

21

Color Circles

Color Circles Shown in Diagrams- 7 (a) a

(a)

b

c

a´

(b)

b´

c´

Fig. 48: Hering. Diagram to illustrate similar hues as ratios of individual hues.

Fig. 43: Grassmann’s color circle (1923).

Fig. 45: Rood’s pigment complementary color relationship diagram (1879). b

b:r= 0.75:0.25

b:r= 0.5:0.5

Fig. 47: Psychologist Wundt’s color sphere (Farbenkugel).

b:r= 0.25:0.75

Fig. 49: Hering. Color circle created from four color crescents.

r

Fig. 44: Basic plan for Helmholtz’s color cone (1867).

Saturated primary colors are located on the periphery.

were all reported to be fascinated by this book.

Rood was also an advisor to color researcher Munsell. Rood’s practical systemization of color formed an essential part of Munsell’s later work.

Fig. 46: Rood. (Upper) Pigment mixing. (Lower) Light mixing complementary color circle (1879)

Fig. 50: Hering’s color circle.

22

Color circles modeled on flower petals Attempts at creating new color palettes Charles Hayter 1761–1835, England

Charles Blanc 1813–1882, France

Charles Lacouture 1832–1908, France

Michel Jacobs 1877–1958, Canada

Hayter’s color circle

Lacouture’s color circle

Portrait artist and architect, Charles Hayter in 1830 published a work entitled A New Practical Treatise on the Primitive Colours covering rules for creating various colors by mixing colors. This volume contains a number of fascinating colored diagrams, but the main color system diagram (Fig. 51) placed at the beginning of the book strangely lacks colors. This may be due to the difficulties posed by working with large numbers of colors. The three primary colors in Hayter’s petal-­arrangement diagram are the same yellow, red, and blue proposed

by Leonardo da Vinci. The three secondary colors are orange, green, and purple. The tertiary colors are olive, brown, and slate gray (bluish gray) ;; he uses slate gray with several varying hues in a number of places. Hayter does not appear to distinguish between additive color mixtures and subtractive color mixtures.

In 1890, French botanist and naturalist Charles Lacouture in Paris published Répertoire Chromatique.

In addition to b o oks on color, Lacouture was a high school teacher and the author of works on moss and flowerless plants. Lacouture’s Répertoire Chromatique included a color chart (Fig. 53) called the trilobe synoptique for analyzing color mixtures. As suggested by the name, colors are arranged in the pattern of three leaves. The red, blue, and yellow on the periphery form the three primary colors, forming arcs from these starting points. Colors vary gradually in six gradations toward the periphery, starting from white at the origin. Red becomes R 1 , R 2 , a n d R 3 , a sys t e m t h a t can perhaps be described as the invention of the color chart. Color charts are typically square grids, but this chart was devised with a unique design right from the start.

Charles Blanc’s color circle Art critic and historian Charles B l a n c i n c l u d e d t h e “ C h ro m a t i c Rose” color circle shown in Fig. 52, representing a flower, in his manual entitled Grammaire des Arts du Dessin.

This book introduced Chevreul’s color theory to various neo-­impressionists, including Seurat.

Jacobs’ color circle In 1923, Canadian-­born sculptor and artist Michel Jacobs wrote the book The Art of Color, in which he refers to the psychological effects of color arrangement and proposes unique theories on color harmony.

Jacobs was a prop onent of the Young-­Helmholtz theory and used the three primary colors red, green, and purple, which he referred to

as the spectral primary colors. The purple used by Jacobs was actually the blue-­violet color used by both Bezold and Hemholtz.

Let us examine Jacobs’ color circle (Fig. 55). The spectral primary colors mentioned above are arranged on a circle, with the three secondary colors yellow, blue, and carmine red arranged in opposing positions from the center. Three complementary color pairs are therefore created by the sp ectral primar y colors and secondary colors. The color circle positions are arranged with opposing convex and concave curves, forming complementary color pairs that create six possible mixed colors.

Jacobs described the configuration of his color circle as an open garland, and it featured orange, yellow-­green, blue -­green, blue -­violet, purple, and scarlet, proceeding clockwise.

Complementary color pairs formed a single f low, such as purple and yellow-­green. The numerous lines drawn on the three garlands separate the complementary colors and alleviate the contrast. Jacobs used the term spectral primary colors, but his color circle ultimately addressed pigment subtractive color mixtures.

Color Circles

Color Circles Shown in Diagrams- 8

Fig. 55: Michel Jacobs, 1923.

Fig. 53: Blue, red, and yellow Trilobe Synoptique mixed color chart devised by Lacouture.

Fig. 51: Hayter’s color circle (1830).

Fig. 52: Painting Compas (partial).

Fig. 54: Lacouture’s color circle titled “Rosesynoptique”.

Fig. 56: Combination of harmonies.

23

24

Bauhaus and color circles The quest for color harmony in design The teaching of color at the Bauhaus represented an aesthetic study of, and research into 18th century theories of color, with a curriculum incorporating the harmony theories of color and sound developed by Newton.

Outside their classes, Johannes Itten, Wassily Kandinsky, and Paul Klee undertook numerous visualization experiments related to shape, color, and tone.

Paul Klee 1879‒1940, Germany

Johannes Itten 1888‒1967, Germany

Fig. 57: “Canon of totality” of color.

Fig. 58: Paul Klee’s “Canon of color totality” diagram.

Itten’s color circle

Klee’s formative theories and color circle

The ethos and methods of Johannes Itten, a leading lecturer on color from 1920 at the Bauhaus, the pinnacle of design education, remain valid to this day. The large number of color frameworks he taught were analyzed using color perception beyond the fundamentals of color, providing the optimum materials for the fundamentals of design teaching. (See Fig. 59, 61, 62, and 63) Itten studied under Adolf Hölzel in Stuttgart, learning all of the color theories, including those of Runge, Goethe, Chevreul, Ostwald, Schopenhauer, and Schreiber.

He went on to collate these classical color theories in his initial experiments. Itten’s color circle can be described as one of the most famous of all color circles, invariably featured in textbooks on color. Together with the 12-­color circle (Fig. 61), the famous color star (Fig. 62) was a two-­dimensional version of Runge’s color sphere (Fig. 29). The most famous aspect of Itten’s color theory is his color harmony theory, incorporating triads and tetrads, but this had already been proposed by Chevreul.

This idea was analogous to the horoscope diagrams widely used in the West, such as those devised by Ptolemy (Fig. 60), Galileo, and Comenius.

During his period at the Bauhaus from 1919 to 1923, Itten established a personal studio inside the Knights Templar gothic-­style building designed by Goethe in a park in Weimar. The mystic nuances noticeable in Itten’s work have clear origins in these surroundings.

Itten resigned abruptly from the Bauhaus in October 1922 following disagreements with the director, Gropius, and color teaching duties passed to Paul Klee.

Paul Klee was the successor to Itten, taking over as professor of color teaching at the Bauhaus from 1923 onward. He, too, has left a number of color circle ideas within his own formative theories, which we will examine here.

The details of Klee’s teachings on color are covered extensively in his various works, such as Das Bildnerische Denken and Beitra zur bildnerischen Formlehre (The Thinking Eye: The Notebook of Paul Klee). Perhaps no writer left as much detailed information on his thought processes with regard UP DPMPS BT ,MFF )JT ¾WF TJEFE NZTUFSJPVT QBMFUUF (Fig. 65) also indicates his thoughts on pigment color mixtures. He also produced diagrams depicting harmonies of color and sound.

A characteristic of Klee’s diagrams is the provision of dynamic laws of motion in which opposing colors are linked by gradations, with emphasis placed on middle gray.

This is a characteristic shared by Itten’s diagrams, which also reflect significant influence from classicists such as Plato, Aristotle, Robert Fludd, and Athanasius Kircher, as well as Runge and Goethe. Fludd and Kircher expressed universal mysticism using various diagrams. However, Klee’s “Canon of color totality” diagram (Fig. 58) brings to mind Aristotle’s theory of light and dark. The bottommost part consists of darkness;; the topmost area is light. The three primary colors of red, blue, and yellow rotate on a plane around the center.

Klee described this arrangement as a “canon” of color. The individual colors vary in width and overlap, creating various intermediate colors (as in Hering’s idea) 5IF EJBHSBN BQQFBST BU ¾STU HMBODF UP be meaningless from a chromatic viewpoint, but it expresses past color theories in a geometric format ¾MUFSFE UISPVHI BO BSUJTUµT TFOTJCJMJUZ

Color Circles

Color Circles Shown in Diagrams- 9

Gelb

Grün

Rot

Cyan

Magenta

Fig. 59: Johannes Itten’s color harmony theory diagram

Blau Fig. 60: From the Latin version of Ptolemy’s Harmony

Fig. 64: Klee’s three-primary color diagram v Fig. 61: 12 color circles.

Color circles developed from the primary colors of yellow, red, blue, orange, green, and violet. s Fig. 62: Itten’s 12-coordinate color star. Each hue has two gradations from the midway pure color to the center and two gradations to black at the periphery. z Fig. 63: Itten’s color solid.

Diagram recreatiung Runge’s color sphere for teaching color theory. The two at the top are the color solid surfaces, and the bottom left is the horizontal cross section at the equatorial pure color plane. The bottom right shows the vertical cross section through blue and green.

Fig. 65: “Basic star shape color plane and compound star” by Paul Klee. Various extreme cases with common equilibrium points connected by gray.

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26

The birth of practical color systems The quest for an international color standard

x Fig. 66: Munsell

also first considered spherical arrangements.

(1905) z Fig. 67: The color

circle patented by Munsell in 1906 had the seven Newtonian colors of red, orange, yellow, green, blue, indigo, and violet.

His concept using 10 colors appeared later.

Wilhelm F. Ostwald 1853–1932, Germany

Ostwald’s “abacus bead” shape color system A multi-­talented scientist, Wilhelm Ostwald won the Nobel Prize for his research on catalysts and chemical reactions. In his later years, he devoted his time to color research, devising his own color system and prop osing a color arrangement method based on the principle: “Harmony Equals Order.” Ostwald’s color system was based on the four primary colors used by Hering, and he designed a grayscale using the Weber–Fechner Law governing the relationship between perception and stimulation. Triangular planes of identical hue are formed by pure colors (full colors) , white, and black at each apex, and 24 of these hue planes are arranged in a double cone to create an abacus bead shape.

Ostwald’s color system was improved in the 1950s to become part of the DIN (German Institute for Standardization) system and was absorbed in similar form in the 1970s into the NCS Natural Color System.

Albert Munsell’s color system Albert H. Munsell 1858–1918 USA

An American art teacher, Albert Henry Munsell in 1905 published A Color Notation, which provided a means of expressing all colors in terms of the three characteristics of color: hue, value, and chroma.

His color solid created using these

three characteristics was based on a central vertical axis for lightness in 10 steps from white (0) to black (10), and with 10 hues arranged at even intervals around the circumference.

The final version differed from the original following improvements, becoming a somewhat awkward shape. This is because the maximum chroma values for each hue vary between 10 and 15, resulting when viewed from above in the uneven arrangement shown in Fig. 71.

Munsell sought to explain color simply, using a wide range of illustrations, such as globes or tangerine oranges to explain his ideas. The diagrams used in his works alone would no doubt be enough to form a single book. While the current Munsell color diagram uses 10 color hues, the diagrams in the 1906 patent application featured Newton’s seven hues. The Munsell color system is explained in greater detail on pages 30 to 31.

NCS color system The NCS (Natural Color System) is a color system used in the Swedish industrial standards. The NCS color system expresses colors in terms of constituent ratios of six psychological elementary colors: white, black, red, yellow, green, and blue. The colors are divided into 10 even steps between the primary colors red, yellow, green, and blue, giving 40 hues. The shape of the color solid resembles the abacus

bead shape of Ostwald’s color solid, but a major difference is that the colors making up the solid are determined based on perceptive (psychological) experimental data.

Reference sources The following references were used in preparing this document. The main resources used are listed below. I wish to thank the authors and publishers concerned.

Other references and recommended reading are listed in the bibliography on page 114.

Academic journals and catalogs: Charles Parkhurst and Robert L. Feller, Who Invented the Color Wheel? , Color Research and Application, Vol.7 Number 3, 1982.

Sven Hesselgren, Why Color Order Systems ? , Color Research and Application, Vol.9 Number 4, 1984.

Mitsuo Kobayashi, The 34th Annual Meeting of the Color Science Association of Japan (2003), Abstract.

Koji Ogata, Chromatics: Chromatography;; Color Theory: Chromatics (contained in Catalog of Western Rare Books at Bunka Women’s University Library).

Books: Akira Kitabatake, Key Works and Illustrations in Chromatics (Yushodo).

Klaus Stromer, Color Systems in Art and Science;; Traditions and Colors (Golden);; Farbsysteme (Dumont).

Rolf G. Kuehini, Color Space (Wiley-­ Interscience).

Frans Gerritsen, Modern Color (Bijutsu Shuppan-­sha);; Evolution in Color 4DIJøFS Publishing, 1988).

Color Circles

27

Color Circles Shown in Diagrams- 10

v Fig. 68: Ostwald’s abacus bead shape color solid w Fig. 69: Ostwald’s 24-color circle

v Fig. 70: View from above the model published

by Munsell in 1915. (20 hues)

v Fig. 72: Swedish industrial standard NCS color solid model

w Fig. 71: Munsell’s 100-hue circle

w Fig. 73: NCS 40-hue (1979)

Y

G

R

B

28 520

Yxy-CIE chromacity diagram

0.80 0 54

The Yxy color space allows color to b e expressed graphically in t wo dimensions independent of intensity.

Plotting the wavelengths of the visible sp ectrum converted into x-­y chromacity coordinates produces the horseshoe curve known as the spectral lo cus (pure color light lo cus/lower diagram, left ). All colors visible to the human eye can be plotted within this curve.

Colors have b een added to the x-­y chromacity diagram on the right f o r c l a r i t y, b u t s o m e c h r o m a t i c s text b o oks recommend not adding color to the chromacity diagram.

The hue along the periphery of the horseshoe varies in the spectral order discovered by Newton. The straight line connecting the two ends of the horseshoe curve is known as the p u r p l e b o u n d a r y. C o l o r s l o c a t e d on this line consist of a mixture of 380 nm (violet) and 770 nm (red) light and are not contained in the solar spectrum. y

520

spectrum locus

53 0

Fig. 75: CIE 1931 (xy chromacity diagram).

Adobe d RGB R

510

0

55

0.70

SWOP O GRACoL A 2 2006 C Coated d #1 K leid Ink I k Kaleido

0 56

sRGB R

0.60 0

57 500

0 58

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y 0 59

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0 60 0 61 0 62

0.30

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y

560 500

480

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770nm

480

470

purple line

380nm x

x

Fig. 74: The xy color chart enables gamut to be plotted for all types of tristimulus value devices such as monitors and printers. Gamut refers to the range of colors that can be displayed by the device.

0

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Color Circles

29

CIE LAB Color space CIELAB color space is a uniform color space recommended in 1976 by the International Commission on Illumination (CIE), written as CIE L*a*b*. This color space (Fig. 76) is relatively uniform perceptually and conforms closely to the red-­green and blue -­yellow scales. CIELAB is widely used in areas involving reflective and transparent products, such as printing and graphic arts.

Adobe Photoshop, for example, uses CIELAB as the internal color space for calculation processing. (Refer to page

White （L＊） CMYK

¦& $PMPS EJøFSFODFT

sRGB

Yellow （+b ＊）

Green （-a＊）

Fig. 77: The upper graph plots the CMYK and sRGB color ranges on the horizontal cross section of the Lab central portion.

Red （+a＊）

Blue way （-b ＊）

Black （L＊）

Fig. 76: CIE L*a*b* (1976).

30

Modified Munsell color system From visual appreciation to digitalization

Munsell notation As mentioned earlier, Albert. H. Munsell (1858-­1918) was an American art teacher who published A Color Notation in 1905, a system that made it possible to describe real colors in terms of three color characteristics.

This color system was based on integers of 10. The color wheel was divided into ten using the five main Munsell hues (red, yellow, green, blue, and purple) and five intermediate hues (yellow-­red, green-­yellow, blue-­green, purple-­blue, and red-­purple), with all hues identified by names.

The center of the circle has

a vertical bar with 0 (black) at the bottom and 10 (white) at the top and achromatic grays in between. This forms the Munsell value (lightness) scale. The distance from the center axis to the periphery is divided perceptually into even gradations, starting at 0 at the center. This distance expresses the Munsell chroma (saturation) for a specific hue.

Munsell’s color system was initially illustrated as a spherical diagram, but was designed so that differences between all colors appear uniform.

after a slash. For example, “5R8/4” indicates a red hue, fairly light, with moderate saturation. In other words, pink. Similarly, “5P3/8” indicates a purple hue, quite dark, but with high saturation: in other words, a grape-­like color.

As can be seen from Fig. 79 on the right-­hand page, the maximum chroma varies according to hue. The solid used to express perceived colors therefore becomes an uneven shape rather than a balanced sphere.

(See Fig. 78)

Modified Munsell color system

Colors are specified in Munsell notation in the form of hue followed by lightness, with chroma indicated Value=5

w Linked online from colormunki (http://www.colormunki.com/ Munsell). Allows 40-hue Munsell simulations.

Fig. 78: Produced by Color Measurement Laboratory, War Food Administration, U.S.D.A.

Munsell’s color space is formed o f p e r c e p tually uniform color divisions. However, advances in color measurement technology in the 20th century led to the establishment of the XYZ color system in 1931, and Judd and a number of other researchers examined the color chart in the Munsell Book of Color in detail to correct a number of discrepancies and achieve compatibility between the Munsell system and the XYZ color system.

This was the Munsell hue locus correspondence diagram for the x-­y chromacity diagram, shown in Fig. 78 to the left. Thus, the Munsell system was reborn in 1943 as the Munsell Renotation System. This has now entered widespread use, and the “Renotation” is often dropped.

Color Circles

Hue

Value

© Agfa

© x-rite

Chroma Fig. 79: Munsell’s three-characteristic explanation.

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34

Color Management in Practice

Setting up the equipment and environment needed for color management has

never been easier. Most promising is the release of the EIZO ColorEdge series of

Adobe RGB-compatible LCD monitors, designed for superb color management.

Ideally, monitors offering high-precision color reproduction allow users to match the colors displayed and printed.

In fact, the creation of color reproduction standards, a major development

in recent years, has benefited both the printing and advertising industries. Print workflows rely on color proofing; now, Japan Color, JMPA colors, and other standards can serve as guidelines in establishing workflows. JMPA colors in

particular make it possible to replace conventional proofing with DDCP or to use inkjet printers instead of presses for proofing. No extra work; simply specify JMPA profiles before output. Those involved know what to expect right from the start, when the original ad has been completed on-screen. Comparing images on ColorEdge monitors to documents printed with JMPA profiles brings you closer to

a perfect match between monitor and proof colors. This requires expert knowledge of software and hardware, and this book can shed some light on the subject. The first step is to try it and see.

W.W. Abney. A TREATISE ON PHOTOGRAPHY, 1918

© DWH Co., LTD.

©iStockphoto.com/wsfurlan

Color Management Basics

35

Color Management Basics

02

©iStockphoto.com/Hello Vector!

36

Wavelengths and color in light Combining red, green, and blue light to produce white was a famous feat by James Clerk Maxwell (1831–1879) in lectures at King's College in London in 1861, where he demonstrated the world's first color photo.

Maxwell also explored how we perceive visible light in the electromagnetic spectrum.

In the 20th century, as we began to understand how insects and many other creatures are physically equipped to perceive phenomena, researchers in animal behavior found that various creatures perceive various wavelengths of light. What we perceive as color, for example, is the specific range of the spectrum that the particular RGB-sensing

Maxwell also established the fundamental principle that light travels in waves, and his research on electricity and magnetism led to the development of the unified model of electromagnetism. Today, both phenomena are identified as manifestations of electromagnetic force. Maxwell showed that light is a form of energy we can describe as an electromagnetic wave and that wavelengths of visible light lie in the range of 380–780 nm (with one million nanometers in a millimeter).

One consequence is that shorter wavelengths of light are refracted more sharply. Research on the spectrum since Newton has made i t p o s s i b l e t o a s s i g n va l u e s t o the spectral wavelengths that are

visible to us. Newton’s original DMBTTJ¾DBUJPOT PG SFE PSBOHF ZFMMPX green, blue, indigo, and violet are too general for work in this context.

As for wavelengths we cannot see (shorter than 380 nm or longer than 780 nm), scientists knew that these waves existed even before Maxwell's time.

Sir Frederick William Herschel discovered infrared radiation, with wavelengths longer than 780 nm, in 1800. This was followed in 1801 by a discovery at the opposite end of the spectrum by Johann Wilhelm Ritter, who identified ultraviolet radiation with wavelengths shorter than 380 nm.

Maxwell correctly concluded that the electromagnetic waves exist at these wavelengths, but that our eyes simply cannot perceive them.

Light radiation, reflection, absorption, and transmission Light can be described by its wavelength, which determines its color in the spectrum. Two factors affect the wavelength of light: radiation and absorption.

Radiation of light: When another form of energy is converted to light energy, light radiates from the energy source. This radiation is generated by chemical or physical processes, such as the burning or heating or cooling of atoms or molecules. It is worth noting here that the definition of “white” light varies.

system of our eyes reveals to us.

ultraviolet rays

Elec

tric Gener

ator

cas oad ti

Br

Radar

ng

At

Vision

dici Me n

e

wavelength（1nm=10-4m）

gy

ic En om er

infrared rays

human being butterfly deep-sea fish

Each animal species perceives color differently.

Animals are equipped with what we may regard as unique optical instruments. The particular biological hardware of one species lets it perceive EJøFSFOU XBWFMFOHUIT PG MJHIU UIBO BOPUIFS species. In each case, perception results from long-­term evolutionary changes to promote survival in various environments.

monkey birds / fowl fish snake 300

340

ultraviolet rays

infrared rays

Color Management Basics

Absorption is the opposite of radiation, occurring when light energy is converted into another form of energy, when the atoms or molecules of an object or medium struck by light absorb the light.

How much light of the various wavelengths is absorbed depends on the chemical structure of the object or medium. Interactions between wavelengths and the structure of UIF PCKFDU DBVTF MJHIU UP CF SF¿FDUFE from or absorbed into the surface.

5IVT SF¿FDUJPOT DBO BMTP CF WJFXFE as radiation occurring after light is partly absorbed.

Transmission of light: Ancient scholars puzzled over the nature of clear materials and the light passing through such materials.

Their confusion arose from a misunderstanding—that color was inherent in the surface of things.

Light passing through clear or semitransparent substances such as XBUFS BJS ¾MN PS JOL JT USBOTNJUUFE through the substance. This occurs when more of some wavelengths of light are absorbed than others as they strike molecules and particles in a substance. The thickness of a particular object determines the extent to which various wavelengths are absorb ed or passed. Only a vacuum fully transmits light of all wavelengths.

For objects that radiate light, radiance can b e measured and charted. Radiance is the relative intensity of light energy radiated at various wavelengths, based on the total amount of light energy. In the chart, yellow indicates the spectral curve for daylight, with the diagonal line indicating values for an ordinary incandescent (tungsten) bulb.

Similarly, ref lectivity can be measured and charted for objects that reflect light. Reflectivity is the ratio of incident light to reflected light at each wavelength. In the chart, NBHFOUB JOEJDBUFT UIF SF¿FDUJWJUZ PG red objects.

Spectral data and spectral curves 0CKFDUT DBO CF CSPBEMZ DMBTTJ¾FE into three categories based on how they interact with light. In each case, spectral curves show how objects affect light of various wavelengths.

The following chart shows examples of several spectral curves. ① Radiant objects (such as daylight or monitors) ② 3F¿FDUJWF PCKFDUT PS PCKFDUT UIBU absorb light ③ Transmissive objects

100

For transmissive objects as well, transmissivity can be measured and charted. Transmissivity is the ratio of incident light to transmitted light at each wavelength. In the chart, green indicates the transmissivity of cyan ink.

A colorimeter can be used to measure the spectral data of any object and derive spectral curves.

T h u s , s p e c t ral data provides a detailed record of the amount of light reflected at each wavelength, TPNFUIJOH UIBU DBOOPU CF DPO¾SNFE by sight alone. Measurements of this kind require an instrument called a spectrophotometer.

Daylight spectra

（%）

Reflectivity of a red object

① Radiant objects

② Reflective objects/ light-absorbing objects

Relative Spectral Power

Light absorption and reflection:

37

80 Transmissivity of cyan ink Incandescent (tungsten) bulb

60

40

20

③ Transmissive objects

Monitor (red phosphor)

0 400

500

600 wavelengths（nm）

700

38

Metamerism and color rendering

Color rendering defined Pu b l i c a t i o n s t h a t d i s c u s s color often address favorable or unfavorable color rendering prop erties, but the underlying concept of color rendering is rarely def ined. It is worthy of initial consideration, since this is a key issue in the context of metamerism.

Color rendering is the effect of the color of the light source on the appearance of color in objects. This characteristic is known as the light source’s color rendering property.

The color rendering index is one way to compare relative performance in this regard.

The suitcoat and pants that appeared to match at the store somehow clash BU B QBSUZ 0S UIF CPVRVFU PG ¿PXFST that looked beautiful at the florist looks dull and lifeless under your lighting at home. There are countless examples.

We can reverse the underlying principle applying in all these cases to create color with a consistent appearance by combining multiple color components. For example, i n s t e a d o f c r e a t i n g g r ay f r o m black and white as usual, we can create the same color by mixing complementary hues such as red and blue-­green, yellow and bluish purple, or blue and orange.

The following figure shows colors affected by metamerism and colors that maintain a consistent appearance. These three products app ear identical under natural sunlight, but incandescent lighting brings out a reddish tinge in two of them. Of course, we can also JNBHJOF UIF PQQPTJUF FøFDU As for ensuring consistent colors through the data used in photographic prints or printing, newer inkjet printers can reduce the effects of metamerism, but a D50 or D 65 light source is recommended for post-­printing proofing. Use the isochromatic samples at the end of this book.

©iStockphoto.com/CreativeLogicConsulting

Metamerism Three requirements are essential in perceiving color: light, objects, and our eyes. Metamerism occurs when these elements are out of sync from their normal relationship. The phenomenon can make two colors that appeared identical under one light source look different under another. Our eyes are susceptible to metamerism, but in fact, the phenomenon also affects other instruments that operate on principles of RGB light mixing, such as scanners and digital cameras.

Realistic examples are often cited in explanations of metamerism.

Buy fresh fish that looks delicious at the deli, and you may lose your appetite when you see the colors under fluorescent lighting at home.

With metamerism

With metamerism

Without metamerism

Color Management Basics those with a white point at 5000 K have a yellowish tinge. In general, this system of notation is only approximate. Of the many radiant light sources that exist, none perfectly matches the characteristics of a black body. Strictly speaking, descriptions of color temperature are thus the correlated color temperatures. The system of notation also applies only to radiant objects. It cannot be applied to reflective or transmissive objects, since the black body model approximates the molecular process of radiation in objects that emit light.

Temperature White of Light Balance

10,000 K

Light Source

Clear blue sky

9,000 K

8,000 K

7,000 K Clouded sky

Relationship of color temperature to the spectral distribution in light sources

6,000 K

Fluorescent Flash or strobe lighting Noon sunlight HMI Metal vapour

5,000 K

9,000 K 4,000 K

7,000 K 6,000 K

Tungsten

3,000 K

5,000 K 4,000 K 3,000 K 2,000 K

400

2,000 K

500

600

Wavelengths（nm）

700

Candle light

Agfa Guide to Digital Photography

Color temperature is a scale used to distinguish colors of light.

Color temperature is measured in Kelvin (a unit of absolute temperature), and values are followed by the symbol K. Color temperature is expressed relative to black-­body radiation, as described below. Although the sun and sky appear to change color between sunrise and sunset, we can express a constant color in terms of temperature relative to black-­body radiation. As a scale for expressing the color of light, color temperature wa s f i r s t p r o p o s e d b y B r i t i s h physicist William Thomson (Lord Kelvin).

A more detailed explanation will clarify these ideas. Because molecules release energy in the form of light as objects cool, all objects emit light when heated. In this context, the theoretical concept of a black-­b o dy, as prop osed in 1859 by Gustav Robert Kirchhoff, is useful. This ideal object reflects and transmits no light whatsoever.

Because all wavelengths of light are fully absorbed, all light emitted is in the form of thermal radiation.

Since we can calculate wave-­ lengths in black-body radiation, we know that the change in spectral curves is constant (as demonstrated by Max Planck in 1900) and can be predicted. A black body glows red at 2400 K and yellow at 5000 K. At 6500 K, it turns white; at 9300 K, it takes on a blue

tinge. The color remains blue even at higher temperatures. This is because the additional wavelengths emitted at these temperatures are too short to be seen.

Next, a system of notation was devised to describe radiant light sources relative to a black body.

Measurements were made to determine the spectral distribution of various light sources. These put light bulbs at 2800 K and sunlight at 6500 K, and people characterized colors at various levels. Computer monitors and televisions have specific white points that affect other colors. For example, monitors with a white point at 9300 K have a bluish tinge, while

Relative Spectrum Power

Color temperature

39

40

CIE RGB, the dominant color space in digital imaging, is not necessarily ideal for color management.

Ever y t hing you rely on in pro -­ duction, from your eyes to devices such as scanners, monitors, and printers, covers a slightly different RGB gamut. In other words, there is a different range of colors between red, green, and blue for each device.

Fortunately, the values representing colors on one device can be conver ted relat ively ea sily into those for other devices. No other primary color system shows special promise as a standard color space for typical applications. However, other colors do in fact lie outside the RGB triangle. For this reason, the International Commission on Illumination (CIE) has devised a new international tristimulus color system, envisioned as the master system for all other color spaces.

T he mo st reliable color spac e s are therefore based on this XYZ c olor spac e de velop e d by CIE .

Photographers and designers rarely work with CIE XYZ directly, but color experts must know about this system, which is used internally when computer software handles color, and in other applications.

CIE hop e d to e st abli sh a n essential shared point of reference for manufacturers of paint, dye, ink, textiles, and so on, used, for example, when specifying product colors.

The historic CIE meeting took place in September 1931 in Cambridge, by coincidence the city where Newton had published Optics. This marked the first international attempt to establish a system for obser ving BOE NFBTVSJOH DPMPS VOEFS TQFDJ¾D conditions of illumination and observation.

The 1931 CIE system defined { a standard obser ver (the f ield of view for obser ving colors) ;; | standard illuminants (light sources);; } the CIE XYZ set of tristimulus values;; and ~ Yxy notation (in reference to a color space and chromaticity diagram), among other matters.

5ISPVHI NBOZ SF¾OFNFOUT UIJT system was improved in the ensuing ZFBST *O UIF EF¾OJUJPO PG UIF TUBOEBSE PCTFSWFS XBT SF¾OFE saw the addition of { perceptually uniform color spaces called CIE L A B a n d C I E L U V ( L* a * b * a n d L*u*v*, respectively) , | a method for quantifying how "close" two colors a re JO U IF G PS N PG ¦& , a nd ot her guidelines. CIE later developed the ¦& 00 (¦ & ) color-­difference equat ion and def ined t he wide sRGB gamut for digital cameras, among many other achievements.

The organization remains a leading authority, setting trends in color TQFDJ¾DBUJPOT

Discovery of tristimulus color perception Thomas Young, who postulated retinal RGB receptors, observed that many colors can be created from the three primary colors of red, green, and blue. These theories were later refined by Hermann von Helmholtz, who presented spectral curves for each color. In practice, it is useful to understand that tristimulus principles form the basis for describing individual colors as combinations of three primary colors (such as RGB) and for deriving HSB and similar color models.

（R） （G）

（B）

v Helmholtz's sketh of estimated spctral sennsitivity of three fundamental color vision processes.（1860）

Color-matching experiment How can we verify this basis for our sense of color experimentally?

The environment shown b elow is used to demonstrate how we perceive color and derive the ratio of constituent colors that match a reference color. Subjects compare the colors of the top and bottom halves of a circle seen through a hole in a screen and respond to questions on the perceived colors. Behind the screen are the two sources of these colors: a trio of red, green, and blue lamps (the three primary colors, to test the tristimulus theory of color perception)

across from a reference light source.

RGB levels are adjusted until the subject feels the top and bottom halves match. This demonstrates tristimulus color perception and makes it possible for us to derive the corresponding ratio of red, green, and blue.

F Target Color White Screen Masking Screen

Test Light

F

Primary Light R+G+B

B G R

Primary Lights

Red, green, and blue light levels are adjusted until the observer perceives the top and bottom colors as matching.

v The Color-Matching Experiment

Color Management Basics technology enabled researchers to gauge this subtle discrepancy, and in 1964, CIE added the supplementary standard observer (based on measurements from a 10° field of view) to account for fields of view wider than 4°. A new notation was introduced to distinguish between these 2° and 10° ¾FMET PG WJFX 9 : 9 )PXFWFS in the absence of indications to the contrary, a 2° observer is still assumed.

∆E* and color difference To calculate how “close” two colors are, we use color spaces with

50 ㎝

8.8 ㎝

CIE color measurements clearly require a controlled environment in several basic respects. First are requirements regarding the observer.

To determine the definition of a “normal” observer, data was gathered as several subjects peered into the color-­matching equipment.

5IF EF¾OJUJPO PG B TUBOEBSE observer specifies a 2° field of view for measurement, since most cone cells (color-­sensitive photoreceptors) are concentrated at the center of the retina. This remains a common standard even today.

In 1964, discrepancies were

JEFOUJ¾FE BGUFS NFBTVSFNFOU XJUI B ¾FME PG WJFX XJEFS UIBO BOE UIF data was reexamined. This problem was especially pronounced for the range of colors from blue to green.

Again, anatomical considerations arose. The fovea centralis is an area at the center of the retina in which more cones than rods are found. But even within a field of view wider than 4°, which includes an area without many cones, color can be discerned.

Only slight discrepancies were noted between color as perceived from these different fields of view, rarely rising to discernible levels.

B u t a dva n c e s i n m e a s u re m e n t

1.7 ㎝

CIE standard observer

41

relatively perceptually uniformity, such as CIE LAB and CIE LUV. The value is called the ¦& (Delta E) or color difference, and a color difference equation is used to calculate this value. Of these two color spaces, CIE LAB is often used in professional settings.

Determining the distance between two colors involves plotting their coordinates, then measuring UIF EJTUBODF±J F DPMPS EJøFSFODF± between the two points.

In the case of CIE LAB, the color difference between the two colors is expressed as ¦& BC XIJDI JT calculated as follows: ¦& BC ¦- 2 + ¦B 2 + b ) 1/2 .

However, this is easier to understand if we describe the practical TJHOJ¾DBODF PG TPNF DPMPS EJøFSFODF values.

Generalizations are as follows: ¦& BC © 5IF EJGGFSFODF JT nearly imperceptible. ¦ & B C © " W F S Z T M J H I U EJøFSFODF DBO CF TFFO ¦& BC ©5IF DPMPS EJGGFSFODF is clear when one color is placed over the other, but the colors look identical when two small samples are compared.

A tolerance level of around ¦& BC JT DPNNPO JO UZQJDBM QSJOUJOH applications. However, values around ¦& BC BSF TJHOJGJDBOU HJWFO UIF performance of current equipment, so an approximate value of ¦& BC 3 may be preferred in the printing industry.

42

Basic Terminology You may encounter a variety of unfamiliar terms in the context of color management. Some terms are defined as they are introduced in this book.

Here we provide a basic reference glossary.

CMY（K）: A model used to produce colors from subtractive color mixing of the three primaries of cyan, magenta, and yellow.

Unlike additive color mixing, in which the three primaries are added to black, color is produced in the CMY model by subtracting particular wavelengths from white. This model is used in printing. To overcome limitations associated with ink

composition, black (K) is usually added to the other colors. The less cyan, magenta, and yellow are used, the more red, green, and blue are apparent. Thus, CMY can be interpreted as a special application of the RGB model. (See Fig. 1) CMM: A n a b b re v i a t i o n o f c o l o r m a t c h i n g module or method. As one component of a color management system, CMMs use profile information, describing device characteristics, for color conversion from the color space of one device to that of another.

1SP¾MFT BSF EFWJDF PS UPPM EFQFOEFOU BOE JOEJWJEVBM QSP¾MFT VUJMJ[F UIF $.. PG UIF same manufacturer or developer.

RAW Data: A n i m a ge fo r m a t i n S L R ca m e ra s .

Although JPEG files offer both DPOWFOJFODF BOE TNBMMFS ¾MF TJ[FT UZQJDBM 4-3 DBNFSBT DBO TBWF ¾MFT JO B QSPQSJFUBSZ RAW data format. The term RAW derives from the fact that data is saved nearly unchanged from the raw information captured by the CCD. Since RAW data is not subjected to image processing to refine sharpness, white balance, or other parameters, professional photographers generally save in RAW format, then use image editing software to achieve the EFTJSFE FøFDUT

Visible Light

0.8

Cyan

Red

RGB monitor gamut

B 0.6

Magenta

CMYK-based printer gamut

Green

H

RGB: A model used to produce colors from additive color mixing of the three primaries of light—red, green, and blue.

Color is produced in the RGB model for equipment that uses color in a way that resembles tristimulus color perception.

Our eyes and all devices such as scanners and monitors use a particular set of RGB colors that differ slightly from others.

In other words, there are as many RGB formats as there are devices. Describing colors in the RGB model thus requires JEFOUJ¾DBUJPO PG UIF TQFDJ¾D EFWJDF

S

0.4

γ＝ 1

0.2

Yellow

Fig. 1

RGB Workflow: Although images or graphics files are traditionally converted into CMYK format before submission for printing, 3(# XPSL¿PXT IBWF FNFSHFE JO UIF QBTU few years. With RGB workflows, after approval from the printing company, images and layout files are submitted i n t h e RG B fo r m a t u s e d by t h e photographers and designers involved, and an optimal conversion method is then applied by the printer. People are NPWJOH UP 3(# XPSL¿PXT JO QBSU EVF UP the many problems that have emerged at the design stage from CMYK conversion of perfectly captured photographs. RGB workf lows are desirable when using wide-­gamut ink such as Kaleido, for

Blue

Fig. 2

which more ink in intermediate colors is required. Here, special profiles must be used in color separation to avoid problems.

HSB: A color model that describes color not as a combination of primary colors but as a combination of the three attributes of hue, saturation, and brightness. Based on the Munsell system, HSB separates the color-­ related attributes of hue and saturation from the attribute of brightness (also called lightness or the Munsell value), which is unrelated to color. As a special case of the HSB model, the Munsell system is perceptually uniform. The HSB model is also generally somewhat more intuitive than the RGB model. (See Fig. 2)

0

0

0.2

0.4

0.6

Fig. 3

sRGB: Standard color space, established as a specification by the International Electrotechnical Commission (IEC) in October 1998. sRGB covers a slightly narrower gamut than color spaces such as Adobe RGB, and the gamut is restricted in certain areas, including hues of emerald green and cyan and hues of orange, bright red, and yellow. For this reason, sRGB may be considered less than optimal for photography, graphic design, or other professional applications, although it generally presents no problems for general use.

ICC Profile: The International Color Consortium (ICC) establishes specifications on color

Fig. 4

management for equipment such as computer peripherals. Data established by the ICC regarding device -­specific color reproduction characteristics (written in conformance with color reproduction standards) are DBMMFE *$$ QSP¾MFT Illuminant: Formal definitions of an illuminant are difficult to understand, and they may refer to a mathematical description of the relative spectral power distribution of light sources. For our purposes, consider an illuminant equivalent to a light source.

In practice, there are several “standard illuminants” (A–F) 5IF TQFDJ¾D POF DIPTFO varies with the application or country of use. The most familiar is probably illuminant D. Illuminant D50 and D65 are

43

Color Management Basics

the recommended light sources for color management.

Color Viewer: Color viewers are dedicated display units used to evaluate colors after printing.

Many formats are available, ranging from small units used by designers and photographers to large units sold with printing presses. Although few Japanese models have been produced in recent years, the color viewers mentioned in this book (marketed by German-­based JUST or U.S.-­based GTI) are popular models. Using JUST color viewers for color proofing on EIZO monitors, viewers can adjust color viewer brightness and intensity in

ColorNavigator after connecting the color viewer to a ColorEdge monitor. (See p. 71.)

Gamut: The range of colors that can be repro-­ duced. The gamuts of common devices such as monitors and printers can be compared—for example—by plotting them on an xy chromaticity diagram.

(See Fig. 3) Page 30 provides a detailed illustration of gamuts.

Gamma: A value that expresses the relationship of image input to output. For example, a gamma of 1.0 would yield a straight line at a 45° angle for equivalent input and output when shown on a graph. All

devices have a particular gamma value, and accurate image reproduction requires an overall gamma of 1, accounting for all devices used from initial image input to ¾OBM PVUQVU (See Fig. 4) Example: Using a scanner with a gamma of 0.45 and a monitor with a gamma of 2.2 yields an overall gamma of 1.

Black Level Adjustment: Adjusting a monitor so that the darkest i m a ge d i s p l aye d (black) i s re n d e re d accurately as black. Monitor calibrators are normally used, but if no calibrator is available, a grayscale image created in Photoshop with about 20 intermediate steps from white to black can be displayed

while adjusting brightness so that the darkest part matches the black of the monitor edge, outside the scanning lines.

Of course, white level and contrast must be adjusted thereafter.

Color System: According to JIS Z 8105-­1982: a series of definitions (using particular symbols), and the system formed by these definitions, intended for precise color matching.

Systems applying to the sequence of colors standardized by the International Colour Association (AIC) are called color order systems. Color order systems were DMBTTJ¾FE CZ UIF MBUF DPMPS TDJFOUJTU %FBOF Judd of AIC as (1) systems combining

E=klogI+C

100

Sensation Intensity (E)

80 60 40 20 0

Fig. 5

colorants, (2) color mixing systems, (3) color appearance systems, and between (1) and (2), color charts for printing systems.

Color Inconstancy: Color appearance varies with changes in the color temperature of the light source. The appearance of paintings and photographic works on display depends greatly on the color of the illumination.

New inkjet printer ink (manufactured by Epson) reduces such color inconstancies.

Attempting to reduce the effect of light sources is, in effect, the opposite of metamerism. (See Fig. 7) Characterization: Calculating average values for the same devices made by a particular manufacturer.

Characterization enables approximation

Fig. 6

PG FRVJQNFOU DPMPS DIBSBDUFSJTUJDT 1SP¾MFT created through characterization are sometimes available from manufacturers.

Calibration: Calibration involves measuring the display or output of a particular device, determining any variance from a predetermined standard, and adjusting the device to eliminate the discrepancy.

Standards used in calibration are either average values derived from several units through characterization or universal s t a n d a r d s . A f t e r wa r d , a p r o f i l e t o compensate for the measured discrepancy with the standard is applied to RGB values created by or transmitted to the device.

0

©EPSON

Fig. 7

Metamerism: A phenomenon whereby two colors match under a particular light source but not under a different light source.

Similarly, under a different light source, colors that originally appeared different m ay a p p e a r i d e n t i ca l . Ta k i n g t h i s phenomenon into consideration, we recommend a color viewer with a D50 or D65 standard light source when proofing on monitors, from printed documents, or in printing environments. (For details, see p. 38.)

Fechner's Law: Law proposed by German scholar Gustav Theodor Fechner (1801–1887), a pioneer in the field of psychophysics, which explores the relationship between sensation and stimulus.

20

40

60

Physical Intensity (I)

80

100

Fig. 8

Fechner discovered a critical relationship between sensation and stimulus.

An example of this relationship is apparent in the fact that even if the actual brightness of a light source is doubled, the increase in brightness is not necessarily perceived to have doubled.

Sensation is not proportional to the quantity of physical stimulus. This relationship is illustrated in the chart.

We now understand that as stimulus increases, the intensity of sensation traces a curved path that gradually attenuates. This is known as Fechner's law, a key concept in color systems, which quantify color. (See Fig. 8)

44

In Practice

Precautions for indoor lighting

First, build an environment for assessing color

Determining illumination is UIF ¾STU TUFQ JO JOUSPEVDJOH B DPMPS management system. Lighting is the critical factor for accurate viewing of color in originals and in the results as displayed on monitors or prints. This requires some thought even in closed environments, where UIF FOUJSF XPSL¿PX VQ UP UIF ¾OBM qualit y check is performed at a single location. By coordinating all conditions in the color-­viewing environment, you can ensure that all off-­site tasks (at the offices of clients, designers, and platemakers and printers at

z A portable viewer from JUST Normlicht of Germany

various times) are performed under

identical conditions, allowing you to build an environment that’s reliable for substituting color data JO %51 PS JO SFNPUF QSPP¾OH The ideal indoor lighting environ-­ ment serves as the basis for meeting the requirements for a variety of colors. Environment s in which

Your monitors, pr inters, and

©iStockphoto.com/Night And Day Images

similar equipment will fulfill the main role when you introduce a color management system. But don't forget the env ironment used to assess color. Here, the key

Specific energy (%)

100

80

Choosing the right light source As the D50 light source, create an environment in which the entire indoor space and the materials t o b e v i e w e d (o r i g i n a l p h o t o s a n d pr inted result s) a re illuminated by f luorescent lighting designed for color evaluation. A variety of these specialized lamps are available, and leading manufacturers offer them EFTJHOFE UP UIF TBNF TQFDJ¾DBUJPOT For example, N-­EDL f luorescent

100

Color Rendering Index AAA-type daylight color

Specific energy (%)

z Fluorescent lamp for color evaluation (an AAA color rendering index)

color is viewed under sunlight are optimal. But since the nature of sunlight varies depending on the weather, time of day, orientation, sea son, a nd locat ion, st a nda rd lighting conditions are determined

by ISO specifications. D50 lighting conditions are considered optimal for printing. Create an environment that will bring you as close to D50 as possible. Keep the following points in mind.

60

40

20

A typical white fluorescent light

80

60

40

20

elements are indoor illumination and your choice of monitors.

0 380 400

500

600

700

Wavelengths (nm)

780

0 380 400 100

500

600

Wavelengths (nm)

700

780

lighting for color evaluation with a color rendering index of AAA would be desirable. Additionally, equipment for viewing the materials of interest (original photos and printed documents) in isolation under ideal lighting is available from suppliers of design and platemaking equipment.

These are sometimes identif ied as “color viewers.” For design and performance reasons, models from U.S.-­ based GTI or German-­based JUST are recommended.

Precautions related to the brightness of indoor illumination Once the indoor illumination is ready, seek the optimal viewing arrangement for original photos and printed document s so t hat only these materials are under the D 50 light source while conditions in su r round ing a rea s re semble a da rk room. By simulat ing a d a rk r o om , yo u c a n k e ep l ig ht SF¿FDUFE GSPN FYUFSOBM TPVSDFT GSPN BøFDUJOH DPMPS FWBMVBUJPOT )PXFWFS g iven t he d i f f ic u lt ie s i mp o s e d by work ing under dark room conditions, as a practical alternative, consider ways to reduce indoor illumination to the extent feasible.

One approach might be to use fewer f luorescent tubes where multiple lamps are installed.

If possible, use fluorescent lighting with louvers to reduce glare from monitors.

Color Management In Practice

Precautions regarding the colors of furniture and walls

45

temperature values, so that the two color patches match most closely under a D 50 light source. (General guidelines are as follows. For D 50 lighting, a ¦& of 1.01;; for D65 lighting, a ¦& of about 1.27;;

Confirm correct lighting conditions Yo u m ay wa nt r e a s s u r a n c e t hat t he environment you have carefully arranged is optimal by switching to f luorescent lighting and taking other measures. You can check illumination using the color temperature meters used by photographers and other imaging professionals. Measure the color temperature of monitor surfaces and color proofing environments.

D50 lighting should register at about 4900 – 5100 K to provide the desired environment. One alternative to expensive color temperature meters is the Simple Metamerism Sample in Appendix B. The card has been QSJOUFE UP BDDPVOU GPS TQFDJ¾D DPMPS

BOE GPS UISFF CBOE ¿VPSFTDFOU MBNQT BU B DPMPS temperature near D 50 , a ¦& of about 1.61.)

Try using the card to check light sources. Note that the performance PG ¿VPSFTDFOU UVCFT XJMM DIBOHF PWFS time, so they should be replaced at regular intervals.

Monitor selection criteria The monitor is the most import-­ ant device in a color management system. Ideally, the colors displayed on the monitor will simply f low from step to step throughout the entire process down through printing. For this reason, a monitor that can reproduce color accurately is essential. Until a few years ago, C RT m o n i t o r s w e r e t h e m o s t commonly deployed;; LCD monitors were regarded as lacking the color a c c u ra c y re q u i re d fo r d e s kt o p publishing and similar tasks. But the emergence of the ColorEdge series completely transforms this state of affairs. Since the release of the ColorEdge CG220, LCD monitors have become the main-­stream for printing and design use.

© Durupa

Even if you dim t he light s, brightly colored furniture or walls NBZ SF¿FDU TJHOJ¾DBOU BNCJFOU MJHIU or light may enter from windows, m i x i n g w it h t h e c o l o r s u n d e r examination, preventing accurate assessments. Ideally, choose relatively dark furniture and use thick curtains to block external light or take similar measures. These decisions should probably be made on a case-­by-­case basis, since imposing rigid working conditions may ultimately hinder productivity.

46

Monitor selection criteria When selecting the monitor right for you, your key criteria should include the number of display colors and their display stability. ColorEdge monitors support calibration. While more mainstream LCD monitors can also be calibrated, making them more viable choices for applications involving color management, measuring the actual gamma curves of convent iona l LCD monitors

reveals that the curves are not linear, which explains why some image areas appear washed out. In contrast, the ColorEdge series (except for the CG19) has 16-­bit internal processing for solid performance rivaling CRT monitors. Support for the Adobe RGB color space with the ColorEdge CG221 makes it an especially good choic e f rom t he st a ndp oint of display colors.

To g ua ra ntee unifor m per-­ formance, each ColorEdge monitor i s me a su r e d a nd t u ne d b ef or e

Monitor viewing environment Once your indoor environment and monitors are ready, prepare the monitor viewing environment itself. Remember that indoor light and other factors can cause glare on glass monitor screens and subtly affect contrast. To prevent glare

from indoor lighting when working under conditions not resembling a darkroom, we recommend using a monitor hood or da rk room cur t a ins. The ColorEdge series comes with a monitor hood as a standard accessory (optional with the CG19 and CG232W). DIY monitor hoods may be used, but always apply a OPO SF¿FDUJWF NBUFSJBM TVDI BT CMBDL velvet to the inner surfaces.

10-bit prossesing Error Percentage

16-bit prossesing Error Percentage

shipment to compensate for variations between individual LCD panels.

Gradation [0–255]

Gradation [0–255]

v The gamma values of each ColorEdge unit are

v A ColorEdge series hood

optimized before shipping.

v Conversion differences between 16- and 10bit processing: 10-bit processing generates more conversion errors, particularly in darker areas; 16bit processing (with ColorEdge monitors except the CG19) results in more precise conversion.

Monitor adjustment The last requirement to ensure faithful color reproduction i s a dj u s t m e n t — s p e c i f i c a l l y, c a librat ion. Broad ly sp ea k ing , there are two methods of monitor calibration. One approach is to use a combination of hardware (in the form of calibrators or spectrophotometers)

and dedicated software, as in i1

solutions. This method offers the mo st ac c u rat e adju st ment a nd management, but requires dedicated equipment. The other approach is to use monitor adjustment software bundled with other applications or operating systems, such as Adobe Photoshop (using Adobe Gamma) and Mac OS X (using ColorSync). (Note: Adobe Gamma is not supported by Mac OS X.) This method lets users make adjustments simply

by clicking to indicate the desired values. It also allows easy profile creation.

Calibration intervals Monitors must be calibrated regularly. Calibration software such as ColorNavigator Agent (p. 71) can automatically notify you when it is time to perform calibration. It is also

a good idea to recalibrate monitors af ter moving them or changing indoor illumination.

47

JUST colorCommunicator × EIZO ColorNavigator www.just-normlicht.com JUST colorCommunicator is the first viewing booth available worldwide that communicates with EIZO ColorNavigator monitor calbriation software tor precisely coordinate the on screen representation and the standardized light to each other.

48

Standard printing colors and soft-proofing Soft-proofing is an approach that has become more widely known since last year, and interest is surging, since it lets the user essentially preview on the monitor how documents will appear after offset or inkjet printing. Actual deployment of equipment for soft-proofing is also taking off. The factor driving this trend is the establishment of standard printing practices designed for consistent quality and greater production efficiency. Updated certification programs for proofing systems (including monitor-based proofing) are also earning industry support, as the certification organizations promote higher accuracy.

As international specifications on color reproduction in printing, the ISO 12647 series specifies basic printing characteristics and requirements for digital proofing. This has paved the way for establishing and introducing standard printing colors in line with regional needs: by Fogra in Europe, SWO P a n d G R ACo L i n No r t h America, and Japan Color in Japan.

Printing characteristics, paper, and target CMYK patch values (L*a*b*) have been tailored to particular printing conditions and standard ICC profiles provided, making it easier to assemble digital proofing systems with inkjet printers and monitors. As a result, soft-­proofing JT TUBSUJOH UP UBLF Pø JO &VSPQF BOE North America.

IDEAlliance Monitor Proofing Systems Certification

100 60

ISO 12647-­7 Digital Control Strip 2009

100

70

30

100 60

100

70

based proofing systems as part of certification for proofing systems capable of reproducing printing colors in compliance with ISO 12647. The criteria for monitors i nc l u d e ( 1 ) sc re e n unifor m it y, (2) monitor profile accuracy, (3) accuracy of gradation characteristics, (4) gamut, and (5) viewing angle characteristics.

What makes the FograCert soft-­ proofing system noteworthy is that the accuracy of monitor display colors is evaluated by examining DPMPS EJøFSFODFT SFMBUJWF UP B NBTUFS print, ensuring ample accuracy not just for checking color and color proofing at the prepress stage, but also in scenarios like viewing color samples on the monitor in printing environments.

(comprising ColorEdge LCD monitors support-­

Standard printing colors and digital proofing, including soft-­ proofing, have caught on in Japan somewhat later than in other re g i o n s . Ne ve r t h e l e s s , a s w i t h Fo g ra Ce r t , t h e Ja p a n Pr i n t i n g Machinery Association (JPMA) has taken the initiative in establishing a certification program for businesses and for processes that reproduce printing colors conforming to Japan Color guidelines. JPMA is also MPPLJOH UP FTUBCMJTI DFSUJ¾DBUJPO GPS EJHJUBM QSPP¾OH TZTUFNT

ing color management as the display device and

'PDVTJOH PO QSPP¾OH (color sample) systems for web offset printing, the SWOP certification program accepted IDEAlliance calibration techniques and characterization in 2006. With the sheetfed offset printing standards of GRACoL, these standards have been updated as certification for proofing systems BQQMJFE UP PøTFU QSJOUJOH 0CKFDUJWF e va l u a t i o n m e t h o d s we re a l s o established for monitor-­based soft-­ proofing systems, which determine any color difference from target A

- B C WBMVFT XIFO QSJOUJOH DPMPST are reproduced on the monitor and measured. This certification program was launched in April 2008. One requirement for monitors is screen uniformit y. Pro of ing systems are certified as supporting printing conditions corresponding to GRACoL C1 and SWOP C3 and C5. In the certification examination, all 1,617 patches of IT 8.7/4 are displayed and measured for evaluation, enabling objective j u d g m e n t b a s e d o n n u m e r i ca l values. Display colors in the center of monitor screens are measured, but to ensure accuracy across the screen, the screen is measured while displaying the three levels of white, gray, and dark gray to check for uneven colors and luminance. A high level of uniformity is required GPS DFSUJ¾DBUJPO An EIZO soft-­proofing system

industry-­standard Adobe Acrobat Professional as the viewing software) IBT CFFO DFSUJ¾FE as a system enabling simulation of GRACoL C1 printing colors. This is a good example of an affordable, low-­maintenance, soft-­pro ofing system.

FograCert Softproofing System Fo g ra , a G e r m a n i n d u s t r y association, establishes and conducts certification for monitor-­

3%

30

100 60

100

70

30

100 40

40 100

40 100

40 70 40

70 40 40

40 70 40

40 70 40

70 40 40

3

10

25

50

75

90

100

Japan Color

Color Management In Practice

(WCS)

the CIE) is used as the basis for color management.

A prominent example among the few applications that currently supp ort WCS is the Microsoft Office 2007 suite. Once Windows Vista color management settings are correctly configured, images XJUI FNCFEEFE DPMPS TQBDF QSP¾MFT are correctly displayed based on monitor color reproduction information (in the monitor profile)

by Office 2007 programs. This is in contrast to earlier versions of Office applications, which process all RGB images as sRGB images. In environments where wide-­gamut

monitors formerly used only in the graphic arts industry are becoming popular as regular monitors and people use Office applications to create and view business documents with images, demand exists for correct monitor profiles specified i n d ev i c e p ro f i l e s a n d c o r re c t EJTQMBZ DPMPST SF¿FDUJOH TPVOE DPMPS management.

Additionally, printer drivers for certain Canon printers can adjust printing colors to suit the BNCJFOU MJHIU JO UIF TQFDJ¾D WJFXJOH environment when printing business graphics for presentation display.

©iStockphoto.com/S-E-R-G-O

Windows Color System

Windows Color System (WCS) is Microsoft's new color management system, introduced in Windows Vista.

WCS is positioned as a platform that SFTPMWFT JTTVFT XJUI *$$ QSP¾MF CBTFE color management systems, although few applications using WCS have been developed or launched to date, and the platform is not pervasive.

Among WCS’s distinguishing features, color conversion infor-­ mation is kept separate from the EFWJDF QSP¾MF BT UIF CBTJT PG PCKFDUJWF measurement;; a gamut-­mapping model makes WCS more versatile fo r c o l o r c o nve r s i o n ;; a n d C I E CAM02 B DPMPS BQQFBSBODF NPEFM SBUJ¾FE CZ

49

50

The ecosystem of color management

©iStockphoto.com/chuntise

Principles in color management

In color document production,

determined by rendering intent. One

a match bet ween monitor colors

of four rendering intents is chosen

applications.

and printed colors matched without

(perceptual, saturation, relative colorimetric,

color management would be a

and absolute colorimetric (p. 96)), depending

remarkable coincidence. Usually,

on the color matching goal. Note

(Note: Preliminary investigations are advisable before creating workflows that rely on printer drive settings. Manufacturers may change these settings without notice.)

color management is essential for

that choosing the wrong rendering

For application color management,

coordinating colors among devices.

intent may lead to poor results. For

simply choose a prof ile for high

Colors will not otherwise match since

professional color management, start

accuracy in the profile settings and

the methods and materials used to

by preparing ColorEdge monitors or

disable color management in the

reproduce color vary from device to

others supporting calibration* (p. 43)

dr iver. RIP color management is

device.

and a measuring instrument as

slightly more sophisticated, but once

suited to photo printing and similar

Although our eyes may sometimes

provided in X-Rite i1 solutions or the

the principles are understood, this

fool us into think ing that colors

Datacolor Spyder series, then calibrate

method can be quickly mastered.

somehow match without color

or characterize*(p.43) each device.

Fortunately, while color settings

management, measurements w ith

Several workflows are conceivable

across applications must be considered,

color instruments generally reveal

for color management involv ing

Adobe Bridge in Adobe Creative Suite

discrepancies. Whether they like it

printed output, depending on the

4 makes it easy to coordinate a color

or not, designers and photographers

environment. These can be broadly

environment comprised of multiple

must learn color matching—or, more

classified as either application

applications. Color management is now

specifically, color management.

color management or RIP color

less esoteric and much more familiar

Color management can be

management. Even in the production

than it once was.

summar ized by the relat ionships

of this book, we distinguished between

shown at right. ICC profiles, files that

these approaches. Al so available

describe the color attributes of each

are color adjustment functions

device, are used to maintain the colors

devised by printer manufacturers

of the original across various devices

and implemented in printer drivers.

to the extent possible. (This is also called

But since PostScript ® files cannot be

gamut mapping.) The parameters that

examined (a prerequisite for most

take priority when matching colors is

printing), these functions are better

Color Scanner

Digital Camera

Color Management In Practice

51

Adobe RGB color space in soft-proofing This refers to accurate colors throughout the entire workflow—in shooting, layout, and printing. This goal of color management, and the system to achieve it, is fundamental to professional production. Only with a complete color management system environment in place can you appreciate the benefits.

An important first step is choosing a common color space, which will serve as the unequivocal standard and prevent needless cycles of color matching. By

Monitor

choosing Adobe RGB as your shared color space throughout the workflow, which may involve shooting with Adobe RGB-compatible digital cameras, editing image data in Adobe Photoshop on Adobe RGB-compatible EIZO ColorEdge monitors, and other steps before conversion to a CMYK format for printing, you can arrange an effective environment for color management, enabling soft-proofing with a higher level of precision.

Inkjet Printer

Color Management in Adobe RGB Prepress & Printing

Print

Design

Photography

Adobe RGB

Adobe RGB

Layout

Layout

Process Image

Masking, Compositing, Adjustment

Enlarging, Reducing, Clipping Paths

Laser Printer

(GLW

Adobe RGB

Check Data

Soft proof instead of hard proof with DDCP’s and inkjet printers

Printing Press Edit while simulating CMYK color space

Edit Adobe RGB image ­Soft proof

No need for Photoshop color engine

By sharing a color space at each stage, the image will be rendered in the same way.

Shoot

52

Color management Colorkeymanagement, to efficient DTP the in print workflows

©iStockphoto.com/Liliboas

Color management plays a greater role than ever, as print workflows evolve. Here, we explore color management and its benefits.

To understand the role of color management in print workf lows, consider the stage of printing in the context of DTP. Print workf lows are becoming fully digital. Moving to digital print workf lows has simplified processes. Clients and designers alike have more opportunities to deal directly with the printing data. The ability to preview the final printing quality during prepress color DTP work paves the way to more efficient workflows and lower printing costs.

But some workplaces have yet to reach this stage. When the final color data cannot be previewed as is normally expected during prepress or if it cannot be guaranteed under the current workflow, we often see clients or designers compromising in color proofing of press samples.

They accept discrepancies between expected and actual colors. Or we see subtle fine-­tuning in prepress or at press, through corrections of the data submitted, ink adjustments, and so forth. Skill in these processes

does not draw on expertise with traditional processes, and ultimately, we must rely on the knowledge of advanced techniques of each individual involved. In many cases, frustrated designers and clients are submitting material as they did before, including color samples or actual objects for reference.

Digital color management is a different way of thinking, a comprehensive approach to color f ro m t h e i n i t i a l s t a ge t h ro u g h printing. Color management systems also account for differences among various environments (client, designer, prepress, and printer) and equipment, providing an environment that maintains a consistent appearance for identical color data. Once the color management system is in place with the correct settings, you can enjoy the benefits of simpler, more efficient color DTP print processes.

Although moving to digital text and digital layout information is also important, moving to digital color data to make it possible to achieve the expected results after printing is critical.

Color management supports DDCP, CTP, LFP, and POD Techniques such as direct digital color proofing and computer-­to-­ plate (DDCP and CTP) skip traditional platemaking in several ways. In CTP, color DTP data is burned directly to aluminum plates from a computer. CTP produces screens just as on film, eliminating the step of traditional film-­based platemaking.

(This book was produced using CTP.)

Direct digital color proofers, a popular type of digital color proofer, take color proofing into the digital age.

Recent large -­format inkjet printers (LFP) come with built-­in color gauges for more consistent output. More businesses are using these LFPs for proofing as part of the color management pro cess.

Mo dels that provide additional support for new orange and green ink are being used for proofing with wide-­gamut ink, such as Toyo Kaleido Ink. If the stages of color proofing and film proofing can be performed with color DTP data and

Color Management In Practice final print quality can be ensured, these steps can b e omitted for simpler, more efficient workflows.

For this reason, businesses moving to CTP and other such technologies should commit to a color management system.

Color management in print workflows Color management in print workf lows enables consistent viewing of color da t a a ny t i m e and anywhere for modification, editing, or revisions. Toward this end, an environment for accurate color management must be created throughout the workflow.

ColorEdge can be instrumental in this fundamental task of building environments.

As Adobe Creative Suite gains more powerful application color management features, even small-­ scale photographers and designers can set up color management environments with relative ease.

In Japan, standards are in place for the entire printing industry.

Japan Color standards are used in commercial printing, Japan Color JCN2002 for newspapers, and JMPA colors for advertisements.

For remote pro of ing environments, Epson's ColorBase printer calibration tool can be used to minimize variations between E p s o n i n k j e t s . Re c e n t m o d e l s also feature built-­in color gauges,

Wide-­gamut printing with ink like Toyo Kaleido Ink is gaining in popularity. The basics of color management are illustrated above;; see p. 110 for detailed information on Kaleido Ink workflows.

enhancing consistency in remote proofing.

The EIZO ColorEdge series is an ideal monitor for color proofing.

All RGB levels (0 – 255 for each color) are factory-­tuned for each monitor to ensure uniformity and exceptionally smooth gradations. Color management is easy, even in separate environments where several people are involved in remote proofing.

Input

Illustration

Pagenation

Print

CTP

M K

Profile

Scanner Profile

53

Monitor A Profile

Monitor B Profile

Monitor C Profile

C

Y

Printer Profile

Printer Profile

Color Management System

Proofing

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All alike at all points

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Printing

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56 For Color Monitors

Principles of LCD monitor colors

Close up cross section • Enlarged view of LCD panel screen

Ordinary computer monitors (including notebook screens) are systems

incorporating transmissive liquid crystal displays and backlights.

The backlight behind the LCD panel

Displaying colors using color filters

goes on, and brightness is controlled by adjusting the light passing through each pixel. Individual pixels are comprised of three components; R, G, and B. Color filters in the three RGB colors are also used to control the

Front bezel:

LCD module:

Diffuser:

Protects the periphery of the LCD module. An optional protective panel can be added to protect the LCD screen.

The orientation of the crystals between the two substrate glasses blocks the transmission of light from the backlight.

Evenly diffuses light from the backlight across the entire screen

wavelength of light that is passed, enabling independent control of red, green, and blue and making it possible to reproduce the colors in the color space (e.g., sRGB, Adobe RGB).

A89 eVcZah VgZ WgdVYan XaVhh^ÒZY Vh

©iStockphoto.com/AndreasG

TN, VA, or IPS.

LCD Driver

LCD Monitors

Backlight:

Control board:

Rear bezel:

Since the LCD itself does not generate light, its light source is the backlight positioned behind the panel.

The core hardware for image display; allows switching of LCD orientation for image or text editing

Featuring heat-vent openings and ergonomic design intended to achieve an easy-to-use interface

Backlight inverter

03 The monitor screen is like the "paper" in DTP design work. However, the way monitors produce color differs fundamentally from what makes paper look white. In DTP design we must know how to make the white displayed on monitors match the white of paper. Of the basic types of monitors, CRT monitors were most common until relatively recently. However, the introduction of ColorEdge LCD monitors that support superb color management has helped make LCD monitors the leading type in recent years for printing and photography applications. Here, we take a closer look at LCD monitors.

LCD Monitors [LCD Monitor Reference]

Backlight sensor: this device increases product life by stabilizing brightness after system startup and automatically correcting for ambient temperature and changes in brightness over time.The light adjustment function is patented by Eizo Nanao Corporation (Japan patent nos. 3171808 and 3193315).

57

58

Basic Monitor Knowledge Popular panel technology LCD flicker 0OF DIBSBDUFSJTUJD PG -$%T JT UIBU UIFZ EP OPU ¿JDLFS

Monitor color settings and adjustment The following settings can be adjusted on LCD monitors.

when viewed. This is clear in comparison to CRTs, in

brightness

which the fluorescent surface has a high response rate

contrast

but brightness changes constantly as the electron beam

color temperature

scans the CRT surface. Even when the monitor shows an unchanging image, the image is periodically refreshed at

The parameter generally referred to as screen brightness

the microscopic level. CRTs with refresh rates lower than

(luminance) is adjusted through Brightness. This changes the

)[ UIFSFGPSF HJWF UIF JNQSFTTJPO PG ¿JDLFSJOH

JOUFOTJUZ PG UIF CBDLMJHIU

In contrast, it is the LCD’s pixels that are periodically

Few LCD monitors enable adjustment of white balance

refreshed. After a refresh, the same state is maintained

by adjusting the brightness of red, green, and blue separately.

and does not change until the values corresponding to

Instead, white balance is adjusted on many models by

the images displayed change. This is because the LCD

changing the color temperature (measured in units of K — degrees

drive circuit is designed to maintain the same voltage

Kelvin), or by choosing settings for warm or cool tones relative

CFUXFFO DZDMFT 'PS UIJT SFBTPO OP ¿JDLFS JT BQQBSFOU BU

to standard values.

any response rate. LCD monitors have a vertical scanning frequency of 60 Hz when displaying digital signals supplied via the DVI port. Analog signals are displayed BU B MPX GSFRVFODZ PG )[ CVU UIJT QPTFT OP ¿JDLFSJOH problems whatsoever.

LCD Monitors

Brightness When grayscale images are displayed from a computer (in increments of 0 – 255, for 256 shades), image brightness is normally adjusted through the Brightness (luminance) setting. Because the overall image is brightened or dimmed while maintaining gradation characteristics, this is the equivalent of Contrast on CRT monitors.

Unlike CRT monitors, LCD monitors have no Black Level setting, since glare does not usually obscure darker image areas. However, to enable monitor-based examination of details in shadow areas, the black level can be set on ColorEdge monitors using ColorNavigator.

59

Color Temperature As with CRT monitors, color temperatures can be set on high-end LCD monitors like the ColorEdge models. However, this setting must be used correctly for the application in question.

Setting the color temperature is equivalent to adjusting the white balance. With the ColorEdge series, this was called white point adjustment.

The term color temperature was originally used in reference to colors of various light sources. Measured in K (degrees Kelv in) , it indicates how hot light sources are.

Hot objects emit bluish white light and cool objects light with a strong red tinge. This helps us quantify the color of light sources.

For graphics applications (viewing and layout of photographic images, for example), 6500 K is considered a suit ab le color te mp e rature. For pr int ing applications, the guideline value is 5000 K; for video images and T V systems, the ideal color temperature is around 9300 K. 6500 K is also specified for the sRGB color space, standard for images on the Internet.

Although the color temperature should m a tch yo u r p a r t i cu l a r application, often a range of production tasks is performed in a given env ironment.

Newer monitors simplify color temperature settings with a one-touch configuration. Some models link monitor settings to software programs, so that the setting switches automatically to 9300 K for video applications, to 6500 K for Adobe Photoshop, and so forth. However, many LCD monitors do not offer color temperature settings at all. Instead of adjustment by color temperature values, these monitors offer only general color adjustments. This may be adequate for certain applications, but individuals who regularly handle digital images should choose models that allow manual configuration of color temperature.

60

Digital uniformity compensation 'PS $35 BOE -$% NPOJUPST BMJLF uniformity of screen luminance and chromaticity is an elusive goal.

Perfect uniformity across the screen is extremely difficult to achieve, due to various factors inherent in how color is repro duced on NPOJUPST 4UJMM HSBQIJD BSUT XPSL in photography, design, prepress, a nd pr i nt i ng dema nd s c er t a i n uniformity. Significant variations in color and brightness that depend

on whether (for example) an image is centered or displayed to the right affect production.

Manufacturers do their utmost to improve the uniformity of LCD p a nel s i n mon it or s , but EI ZO IBT UBLFO UIJT POF TUFQ GVSUIFS developing a special ASIC chip that compensates for unevenness at the signal level for superior image uniformity. The Rchip 255 significantly improves even the uniformity of 255 G mainstream panels, as demonstrated 255 to the right.

B L u m i n a n c e u n i f o r m it y i s

Software Calibration

addressed in ISO 126 46, which establishes a set of requirements for soft-­proofing monitors. To ensure uniformity, the standard specifies that luminance may vary by no more than 10% at nine points around the screen relative to a central point.

We c on sider t h i s t he m i n i m a l

requirement. Monitors with EIZO circuitry for digital uniformity 255 R 240 compensation achieve a ¦& value of 3 or better relative to the center G 230 across a wider area of the screen.

B

255

v Powerful processing from a new ASIC chip ColorEdge monitors are equipped with a newly developed application specific integrated circuit (ASIC) chip that provides internal 16-bit processing for accurate rendering of color image data. This powerful color processing enables smooth tonal transitions and enhances visibility in shadow areas.

255

Hardware Calibration adjusting white and levels of R and G strength (brightness) inside the monitor

R

255

G

255

B

graphics board output data（RGB）

255

R

240

G

230

B

If images are more yellow than desired

Ca librat ion adju st s de v ic e characteristics to restore them to a specific state. Monitor calibration uR s u a l l255 y e n t a i l s a d j u s t iRn g t h255 e monitor to restore gradat ion 255 Ga r a c255 ch t er i s t ic s a nd lu mGi n a nc e (corresponding to white color temperature

255

B

255

and gamma values) to a particular state,

but few monitors enable adjustment

R255 255 G

255

B 255

255 Adjust close to the ideal white

Software-and hardwarebased calibration

B

If images are more yellow than desired

without changing graphics board output data

255

If images are more yellow than desired

of these characteristics. Software c a l ib r a t i o n m e a s u r e s m o n it o r colors, after which any divergence from the target values is corrected at t he stage of output f rom t he graphics card to adjust the display. the problems 255 RUnfortunately, associated with this method include G 255 uneven g raysca le repro duc t ion and color casts from the (tone jump)255 B reduc t ion of one or more RGB levels.

R

255

R

255

G

255

G

255

255

B

255

B

Ideal white

The ColorEdge series and other high-­performance LCD monitors are calibrated with built-­in features t hat adju st t he br ig ht ne s s a nd gradation characteristics of each RGB color independently, functions originally performed by special TPGUXBSF 5IJT JT LOPXO BT IBSEXBSF ca librat ion. Since t here is no need to modify RGB output from computers, this provides a smooth, faithful grayscale display.

v Before adjustment

v After adjustment Color-coded representation of the ∆E*ab distribution across the screen relative to the center, measured at 128 levels of gradation.

LCD Monitors

Monitor-computer video interface %FDJEJOH PO BO BOBMPH PS EJHJUBM MJOL CFUXFFO UIF computer video port and monitor is one matter;; choosing the interface format is another.

Computer connector and single formats Connectors on the monitor PC

Video connectors

D-Sub 15pin

DVI-I

DVI-D

DisplayPort

Macintosh

D-Sub 15 pin

○

○

×

×

DVI-I

○

●

●

×

Mini DisplayPort

○

●

●

×

D-Sub 15 pin

○

○

×

×

DVI-I

○

●

●

×

DVI-D

×

●

●

×

○

●

●

●

＊1

Windows

DisplayPort

＊2

○ Analog connection

● Digital connection

smaller individual dots, so the same image appears smaller than on low-­resolution monitors. Typical examples are given to the right.

Resolution 1024 × 768 1280 × 1024

Screen size DPI 15" 85 17" 96 19" 86

Typical monitor

21.3"

94

EIZO ColorEdge CG211

20.1" 22.0"

98 90

EIZO FlexScan S2031W

1900 × 1200

17"

102

"QQMF .BD#PPL 1SP

1920 × 1200

22.2" 102 23" 98 24.1" 94 21" CRT* 87 22" CRT* 85

EIZO ColorEdge CG221

Standard monitor Standard monitor EIZO ColorEdge CG19

vDVI-D 24 pin

1600 × 1200 1680 × 1050

× Conection not possible

EIZO ColorEdge CG222W

EIZO ColorEdge CG242W

1280 × 1024

Screen size and resolution (pixel count) are basic parameters for monitor performance. The resolution you choose in an LCD panel should generally match the EJTQMBZ NPEF ZPV XPSL JO 5IF GJSTU TUFQ JT EFUFSNJOJOH XIBU TDSFFO SFTPMVUJPO ZPVS XPSLJOH FOWJSPONFOU requires.

2560 × 1600

29.8"

101

EIZO ColorEdge CG301W

2560 × 1600

29.7"

101

Apple Cinema HD Display

Horizontal × vertical

Name

Aspect ratio

1024 × 768 1280 × 1024 1680 × 1050 1600 × 1200 1920 × 1200 2560 × 1600

XGA SXGA Wide SXGA+ UXGA Wide UXGA Wide QXGA

4:3 5:4 16:10 4:3 16:10 16:10

Monitors in various screen sizes at the same resolution are now available, and users can choose the desired format. A guideline in this regard is DPI, or the number of dots per inch. Monitors with higher DPI values have

vDVI-I 29 pin

Apple Cinema HD Display

Monitor size and DPI

Standard numbers of pixels in LCD monitor

vD-Sub 15 pin

EIZO FlexScan T966 Mitsubishi RDF221S

v DisplayPort

*For CRT monitors, the figures shown reflect an aspect ratio of 5:4 and WFSUJDBM NFBTVSFNFOU NBUDIJOH UIF FøFDUJWF EJNFOTJPOT PG UIF $35 TDSFFO

v Mini DisplayPort

5IPTF VTFE UP XPSLJOH PO PS JODI $35 monitors at a resolution of 1280 × 1024 would feel comfortable with the display size of LCD monitors with a comparable DPI: 19-­inch monitors at a resolution of 1280 ×1024. Another consideration is the trend in recent years toward widescreen LCD monitors, which offer B CSPBE XPSLJOH BSFB 6TFST MPPLJOH UP VQHSBEF GSPN a square 17-­inch LCD monitor (1280 × 1024) to an LCD monitor would feel comfortable with the comparable screen height offered by a 20.1-­inch widescreen model (1680 × 1050) XJUI UIF BEEFE CFOFGJU PG B MBSHFS XPSLJOH area.

*1 Monitors lacking a video connector that can be directly plugged into a Mini DisplayPort interface must be connected via a Mini DP-DVI or Mini DP-D-Sub adaptor. *2 Monitors lacking a DisplayPort connector are connected via a DP-DVI or a DP-D-Sub adaptor.

However, some graphics boards may not support a connection that uses a DisplayPort adaptor.

61

62

Monitor calibrators Tools for monitor calibration and device profile creation Monitor performance changes slightly over time, and regular calibration is required. A monitor calibrator,

v X-Rite's new ColorMunki is positioned between i1 Display

which employs a sensor, is also needed to ensure

and i1 Pro and differs slightly from the approach of these solutions. Two formats are available: Design and Photo (for designers and photographers, respectively). Both offer equivalent hardware performance.

consistency among multiple monitors of the same kind.

Manufacturers now offer sensors at various price

v Datacolor’s Spyder3

points, including the X-Rite i1 solutions and the Datacolor Spyder series.

EIZO ColorEdge monitors are compatible with typical sensors from X-Rite, Datacolor, and other manufacturers intended for a range of design and printing applications. The ColorEdge series was developed to set the standard in LCD monitors for superb color management, and these monitors emphasize both high performance and ease of use. ColorEdge software (ColorNavigator) can be used with i1 solutions as well as Monaco Optix XR and DTP-94. As for calibrators from other manufacturers, support for the Datacolor

v The new design of the i1 Pro ruler, with significantly improved usability.

Spyder series was added in ColorNavigator 4.0.

ColorNavigator 5.1.2 introduces support for the new ColorMunki solution from X-Rite.

Download the latest version of ColorNavigator from the EIZO website. http://www.eizo.com v X-Rite’s i1 Display 2.

colormunki photo TM

MONITOR TO PRINT MATCH LIKE NEVER BEFORE

ColorMunki is an all-in-one color control, creation and communication solution that lets you calibrate your monitor, projector, and printer so they all match. With this new solution, you can also send your images with DigitalPouch™ and create unlimited color palettes! So whether you work on a PC or Mac, ColorMunki is the innovative new way to bring your photos from screen to print accurately, simply and affordably.

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X-Rite, the X-Rite logo, ColorMunki, and the ColorMunki logo, are trademarks or registered trademarks of the X-Rite incorporated in the United States and/or other countries.

All other trademarks are properties of their respective owners X-Rite Incorporated 2009. All rights reserved.

64

520

53

0

CIE1931 (x,y) Chromacity diagram

0.80 0 54

Adobe d RGB R

510 0

55

0.70

SWOP O GRACoL A 2 2006 C Coated d #1 K leid Ink I k Kaleido

0 56

sRGB R

0.60

v Comparison of SWOP GRACoL 2006 and Adobe RGB (white frame) color spaces. The Adobe RGB color space fully covers the Japan Color color space.

0

57 500

0 58

0.50

y 0 59

0.40

0 60 0 61

490

0.20

0 63 0 64 0 66

Created in ColorThink

0 62

0.30

v Comparison of SWOP GRACoL 2006 and sRGB (red frame) color spaces. For areas of the spectrum such as green, cyan, and yellow, the sRGB color space does not include the entire SWOP GRACoL 2006.

480

0.10

Comparison of color spaces 470 0

46

0

0.10

0 44 20 4

3380〜410

0.20

0.30

x

0.40

0.50

0.60

0.70

The above graph represents the reproduction range of Adobe RGB, sRGB, Japan Color, and Kaleido inks. Since most sRGB and Japan Color spaces are included within the Adobe RGB space, using Adobe RGB for the workspace in color management ensures most colors used for design preparation can be displayed on your monitor.

Belgium Frence Austria

O T H

1611

United Kingdom

O LD G WATER

1772

1650

Francis Glisson Color scale devised by the British physicist Francis Glisson. Blue, red, and yellow are located between black and white extremes, with the horizontal line forming the grayscale.

1613

1704

1629

Moses Harris In his work Natural Color System, entomologist and engraver Harris devised two different color circles using red, yellow, and blue (prismatic color circle) and orange, green, and purple (compound color circle).

Athanasius Kircher Learned illusion scientist Kircher explained the diversity of color by expanding on Aguilonius's diagram, which was itself based on Aristotle’s

Forsius Color solid devised by the Swedish mathematician Forsius. This is the world's first color solid. The color names are written by hand, with the center axis representing achromatic colors.

Russia Germany

EARTH

Holland

Aristotle Four-element, four-characteristic diagram created by Aristotle, the polymath of Ancient Greece.

Aguilonius Light theory scientist Aguilonius devised a color diagram based on Aristotle's theory, also incorporating ideas borrowed from Pythagorean musical scale relationships.

Phase-transforming this diagram suggests a six-color color solid.

1853

RY

Sweden

1810

D

Greece

1766

1646

FIRE

ET W

* The diagrams included here are representative, not exhaustive. For further information, please refer to more specialized books or documents.

s

[ History of Color Systems ]

A feature in this chapter covering color circles omits a large number of other important color system diagrams, since the selection of illustrations focused on diagrams. We therefore arranged the color system diagrams in chronological order.

Studying color systems reveals a wide range of forms devised during the past 3,000 years, with bridge support styles, cones, pyramids, triangular columns, cubes, spheres, hemispheres, and petal shapes, in addition to circles, pointing to the fertile ground of human imagination.

BC350 AIR

APPENDIX A

Johann Heinrich Lambert German physicist and mathematician Johann Heinrich Lambert is renowned for his Lambert projection for mapping. This pyramid-shaped color sample is said to have been created to allow textile craftsmen to check textile stocks.

1772

Sir Isaac Newton Newton's color circle with the seven colors of the spectrum appearing around the circumference, demonstrating how mixing the seven colors of light creates white (in the center of the circle) and drawing an explicit parallel to the seven tones of the musical scale.

1745

Water

Ignaz Schiffermüller Austrian entomologist Schiffermüller created what was probably the world’s first color circle to use continuous gradations. The four primary colors red, blue, green, and yellow are indicated around the circumference of the color circle, together with secondary colors, for a total of 12 colors.

The diagram includes allegories with rainbow themes at each of the four corners, suggesting Schiffermüller confused mixtures of light and mixtures of pigment colors.

1809

Otto Philipp Runge Runge, an artist, corresponded with Goethe about color. He assigned the three primary colors of yellow (The Holy Ghost), red (The Son), and blue (The Father) to the Holy Trinity. His color sphere was later praised and adopted by the Bauhaus.

1810 Johann Wolfgang von Goethe The color circle devised by Goethe used the six colors of crimson, orange, yellow, green, blue, and violet, minus the indigo forced into the system by Newton. This was the first diagram to pair residual complementary colors (crimson/ green, orange/blue, and violet/yellow).

1830 Charles Hayter Hayter created a color circle arranged like rose petals. He used the three primary colors of red, yellow, and blue, three secondary colors of orange, green, and purple, and three tertiary colors of olive, brown, and slate gray (bluish gray).

1841

Hermann Günther Grassmann Grassmann's color circle developed Newton's color circle, moving the division between the red and violet to the 12 o'clock position, and including intermediate colors on the inside aligned with the 12 o'clock position of B and H on the Fraunhofer spectrum resolution diagram.

1861

Michel-Eugène Chevreul Chemist and early color harmony theorist Chevreul devised a color solid to express hue, tone lightness and darkness, and color turbidity. This color solid was hemispherical, with white at the center, pure colors at midpoints, and black at the periphery.

1867 Hermann von Helmholtz Helmholtz reevaluated Thomas Young's threeprimary color theory, which did not win wide recognition or acclaim when first published, publishing the Young-Helmholtz theory. The diagram on the right was created by overlaying Maxwell's physiological three-primary color triangular shape and spectrum locus.

1867

1868

1889

William Benson British architect William Benson published the Cube of Colors model in his work Principles of the Science of Colour, likely the first three-dimensional color system.

A number of center axes intersect to form the interior of the solid.

The colors at the intersections are indicated on the periphery of the diagram.

Despite a distant resemblance to the 216-color Web safe RGB color cube, the colors are not assigned numerical values.

The colors at the intersections are given pigment color names.

Charles Henry Henry's color circle placed black at the circumference, a clear debt to Chevreul. The pure colors for each hue were presumably arranged midway in the circle, but this is unclear due to limitations involving printing technologies.

1876

1890

Wilhelm von Bezold: Color circle published in 1876 by Bezold in his work Color Theory (right). The center diagram provides an exterior view of the color solid, while the diagram above shows the base. The apex of the cone is black.

The diagram on the left predicts mixed colors on the color circle based on Newton's laws on gravity.

1876

1893

Irozu-Mondou Color circle published in the early Meiji Period Irozu-Mondou textbook. The illustration is Field's color circle, which reached Japan via elementary school textbooks written by an American named Wilson.

1878

Canada Argentina Japan International Standard

b

Black

Robert Fludd British physician and mystic Fludd devised a seven-color (red, orange, yellow, white, black, blue, green) color wheel.

© DWH Co., LTD.

（Yellow）orpiment Tobias Mayer In addition to contributing to methods for determining longitude, the astronomer Mayer devised a color solid expressing the three primary colors, using pigment names and combining dark and light tones.

Thomas Young The able British physician Young proposed a theory of the three primary colors RGB based on his research on the nature of perception. This diagram is a color diagram published as part of his lecture materials.

George Field: Chromatic researcher Field is renowned for achievements in developing pigments. His color circle largely incorporates Aristotle’s theory and Goethe's color circle.

Charles Blanc Art critic and historian Blanc included the color circle called Chromatic Rose, resembling a flower, in his practical guide Grammaire des Arts due Dessin.

Ewald Hering Physiologist Ewald Hering's psychological four-color diagram. The two color circles created by Hering are easily understood when overlaid as shown on the right.

Albert Bourges A pioneer of standardization of colors in this field, American photographer, sculptor, and inventor Bourges published A Notation System in 1918, which used the polychrome system to distinguish colors and explain how these colors could be used in graphic art.

1895

（Yellow） orpiment

y b:r= 0.75:0.25

b:r= 0.5:0.5

g

Wilhelm Ostwald The color solid devised by Ostwald used an abacus bead shape comprising pure color levels, white levels, and black levels for 24 hues. It was designed using Hering's four-color theory and the Weber-Fechner law for correlations between perception and stimulus in the grayscale.

1918

Hermann Ebbinghaus German psychologist Ebbinghaus devised a color solid formed of two square pyramids arranged base to base.

r

Albert Henry Munsell Art teacher Munsell divided color space into hue, lightness, and chroma. The color samples initially created to be perceptually uniform were later refined and corrected based on color measurements to become the representative color system for expressing colors using the interchangeable XYZ format.

1916

Charles Lacouture Botanist Lacouture created a color chart evoking flower petals, clearly intended to serve as a chart for practical use rather than as a color system.

United States of America （Yellow） orpiment

1905

1923 August Kirschmann: German psychologist Kirschmann, a descendant of the great Wundt, devised a color solid involving an inclined color circle on the center equator (with yellow closer to white), based on the notion that purple was darker and therefore closer to black than yellow

Michel Jacobs Canadian-born sculptor and artist Jacobs published a book entitled The Art of Color in 1923, proposing a color circle which he called “open petals.” It featured spectral primary colors on the periphery, with three secondary colors yellow, blue, and carmine positioned at opposing positions from the center to the periphery. The hue arrangement used opposing concave and convex shapes, forming complementary color pairs, resulting in six color mixtures.

1929

1947

Arthur Pope This is the double cone-shaped color solid devised by art teacher Pope.

From above, it features 12 pure colors as in Itten’s work, but when viewed from the side, it features a center achromatic axis in nine gradations from white to black, numbered in reverse of Munsell's scheme. The pure color equator is inclined in accordance with darkness, producing an irregular shape. This solid was created based on Pope's color order system and color harmony theory.

1976

W

CIE L*u*v color system The XYZ color system is an excellent system for expressing individual colors, but is not suited to expressing mutual color differences. This is because physical color space does not appear uniform to the human eye. The color space created in 1964 by MacAdam by converting an xy color diagram was used by the CIE to create the CIE L*u*v color system in 1976.

15

10

PU

Julio Villalobos: This acorn-shaped color solid was devised by Argentinean chromatic researcher Villalobos.

Among his works, Villalobos proposed a hexagonal color circle called the Chromatic Hexagon and published the Villalobos Atlas.

1931

1955

CIE 1931 The CIE (Commission Internationale de l’Eclairage) produced a color system expressing colors in two dimensions on a graph independent of intensity.

Plotting the wavelengths of the visible spectrum converted to x-y coordinates creates a horseshoe-shaped spectral figure on which all visible colors can be plotted. CIE 1931 is one of the most widely used of color systems.

Robert Luther & N.D. Nyberg Closed three-stimulus value vector space color solid devised by the Austrian physiologist Luther and Russian mathematician Nyberg.

All object colors can be contained within this solid shaped like a shark egg sac. This color solid involves angular edges rather than smooth surfaces.

RE

S

HUE

5

S

550

570

D65

590

600

650 700nm

A

500 D50 C

490

480

470

450 400nm

1976

S

DIN color system DIN (Deutsche Industrie-Norm Farb Color System) is a modified German industrial standard based on Ostwald's color system.

This system was established in 1955. As part of this system, a color chart featuring 589 colors determined by hue, saturation, and intensity was issued in 1960. The DIN color system resembles a cut diamond.

M2 D65

M1

1934

1960

Faber Birren Color solid devised by Faber Birren, who contributed to industrial color research in the 20th century. It consists of uniform hue patches for pure color, white, and black, with the center turbid colors named as tones. The upper left diagram indicates the relationship for the seven elementary terms within the hue cross-section.

1944

1975

Douglas L. MacAdam MacAdam, a member of the Optical Society of America, was a chromatic researcher whose work contributed to CIE color difference evaluations.

With its manta ray shape, this figure is surely one of the most unusual designs used for color systems.

J. Frans Gerritsen Dutch chromatic researcher and teacher Gerritsen published a three-dimensional hue-intensitysaturation perceptual diagram in his work Color: Optical Appearance, Physical Phenomenon, Art Expression Medium. The center axis varies from white to black in 20 gradations, while the primary colors rise and fall in a rollercoaster-like locus.

b:r= 0.25:0.75 MacAdam's color system broken down into 21 parts. Reprinted from Klaus Stomer's FARBSYSTEME.

1979

OSA-UCS System: An ideal color system published in 1960 by the Optical Society of America based on research begun in 1947. Under this system, all perceptually uniform colors can be expressed by points at uniform distances in color space. The structure described by this system was an eightsided solid formed of 12 equidistant colors (A to L) with color 0 at the center of a rhombohedral lattice. The system did not enter widespread use.

NCS (Natural Color System) Emphasizing colors as experienced subjectively, this color system (a Swedish industrial standard) extends the ideas of Goethe. It is widely used in Europe and is especially easy to use in design applications.

1999 G

GB

M

B

GR

R

Akira Kitabatake A chromatic researcher with an arts background, Akira Kitabatake was involved in devising numerous color order systems and color name systems in Japan. The diagram shows one such system: The Hue & Tone Color System: CCIC (Chamber of Commerce and Industry Color Coordination Chart 285).