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Illustrations contained in this Color System were featured
in the 1993-2002 Art Calendars of Dainichiseika Color & Chemicals
Mfg. Co., Ltd. to disseminate the teachings of colors to the
public. Any reproduction is strictly prohibited.
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 CIE1931
Standard Colorimetric System
(XYZ) |
A
system commonly employed in expressing colors is called Colorimetric
System and the CIE 1931 Standard Colorimetric System introduced
here is the basic format of color expression. The CIE 1931
Standard Colorimetric System was established at the 1931 conference
of Commision Internationale de Iﾕツlairage (CIE) as a means
for precisely defining the color of light. Based on the principles
of the trichromatic system, the light for each color, formed
by combinations of the three primary colors (red, green and
blue violet), is assigned a numeric value.
Monochromatic spectra are lined up on the perimeter of the
curved spectrum locus in the x, y chromaticity diagram
as shown. The linear section is called the purple boundary.
Moving toward the central section, you get the intermediate
colors and at the center itself you get white illuminant.
All the colors of light are contained in this diagram and
each one can be defined using the x, y values together
with light intensity.
Although the use of a such a diagram showing the colors of
light is not an accurate method for color printing purposes,
we thought it would make our subject more comprehensible to
the general reader.
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CIE
(1976) L*u*v* Color Space
Difference
limen range in u*v* chromaticity diagram |
L*u*v*
color system and L*a*b* color system are both uniform
color spaces that were adopted in 1976 by Commission Internationale
de lﾕツlairage (CIE) and are also referred to as the CIE LUV
color space.
The diagram consisting of u'v' coordinates, the chromaticity
values of the above color system, is called the u'v'
chromaticity diagram and is also referred to as the CIE 1976
UCS (Uniform Chromaticity Scale) diagram.
Uniform color space refers to a color space with a sensuously
uniform scale property, a color space in which the sensuous
differences of uniform luminance colors in all areas of the
chromaticity diagram lie in more or less geometric distances.
The XYZ color system, the basic color system, was adopted
by CIE in 1931 but this system does not have the properties
of a uniform color space.
In 1942, MacAdam announced the drawing of an ellipse that is
interrelated to the human difference limen on the xy chromaticity
diagram by referring to the disparities seen in the color matching
experiment that uses monochromatic light.
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It is the so-called MacAdam ellipse. According to this ellipse,
between the ellipse of the purple domain and that of the green
domain, there is a ten-fold difference between the longest and
shortest diameters. Thus, in the purple domain, just a tiny
color difference makes the colors look different while the same
does not apply to the green domain.
To further clarify these results, MacAdam has enlarged the size
of the ellipse ten-fold, but in the ideal uniform color space,
the ellipse must be a circle and the size must be uniform.
The L*u*v* color system is the XYZ color system
with converted coordinates; it is a diagram in which the MacAdamﾕs
ellipse and the 4 points where the long diameter and short diameter
intersect have been converted to u'v' values, transferred to
the u'v' chromaticity diagram and linked by an arc on a geometric
plane.
If we compare it with MacAdamﾕs ellipse on the xy color chromaticity
diagram, there is little disparity in size and we can estimate
that it is now closer to the uniform color space.
That is why the L*u*v* color system or L*a*b*
color system is being used as the color system to calculate
the color difference instead of the XYZ color system
that
is not suitable for expressing the color difference.
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| CIE
(1976) L*a*b* Color Space
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The
L*a*b* color system is based on a uniform color space
CIE LAB (L*a*b* color space). In a uniform color space
the distanse between two points (two colors) is nearly proportional
to the perceptual color difference. The L*a*b* system
is recommended by CIE (Commission Internationale de lﾕツlairage)
not only for specifying objects-colors but also for calculating
color difference.
The L*a*b* color system is often used in Japanese industry
as a standard color system in the field of color management,
as well as color reproduction, such as color photograph, color
facsimile, color print, color copy, etc.
In order to assist in further understanding of colors in process
printing, the color reproduction range produced by the three
primary colors, yellow (Y), magenta (M), and cyan (C), is
represented in the L*a*b* color space.
The positions of colors produced by printed layers the three
primary colors are plotted in the ground plan a*ﾑb*
which gives a birdﾕs eye view.
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| Munsell
Color System |
In
terms of the basics of color system i.e., we are exhibiting
the representative color system for describing the color of
objects.
The diagram shown here is used as a scale for object color.
It displayes the color solids of the Munsell Color System, the
one most commonly used in Japan and the United States.
The Munsell Color System, first published in 1905, was created
by Albert H. Munsell (1858-1918) an American painter and art
teacher.
Munsell described the system he created in his "Atlas of
the Munsell Color System".
A later work, the "Munsell Book of Color" based on
his Atlas, was first issued in 1929. In 1943, the Colorimetry
Committee of The Optical Society of America scientifically revised
Munsell's work, reissuing it as the Munsell Renotation System.
It is this revised version which is commonly known today at
the Munsell Color System.
In Japan, the Munsell Color System has been adopted as JIS Standard
Color System for object-color.
In
the Munsell Color System, a single color is represented by three
separate parameters (three dimensions) of color: hue(H), value(V)
and chroma(C).
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Hue expresses the basic quality of the
color; there are a total of ten hues consisting of the five
basic hues "red(R), yellow(Y), green(G), blue(B) and
purple(P)" and five intermediate hues :"yellow red(YR),
green yellow(GY), blue green(BG) , purple blue(PB) and red
purple(RP)." These form a hue cicle arranged in sequence
on the circumference. For each hue, there is a number from
0 to 10 placed before the symbol for the hue. It denotes value,
the measure of lightness. The lightest white is given a 10
and placed at the top, while black is given a 0 and placed
at the very bottom. Between these two extremes, shades of
gray are arranged in perceptible equal steps. Chroma is the
measure of the saturation of color. The central axis of achromatic
color is defined as 0 and the scale is arranged concentrically.
The farther one moves away from the center, the greater the
saturation of the color. The three dimensions of color - hue,
value and chroma - indicated also by numbers to the right
of the decimal point, are utilized as an accurate yardstick
for representing object-color. The steps employed are set
up so that the degree of differentiation between each step
is perceived as equal. A value differential of 1 and a chroma
differential of 2 are set up such that they are perceived
visually as having the same degree of difference.
In this diagram, hue is placed on a scale of 40 marked off
at intervals of 2.5, value is placed on a scale of 10 marked
off at intervals of 1 and chroma is marked off at intervals
of 2. With respect to chroma, the ceiling value for color
saturation will vary with each hue.
Although printed reproduction does not allow for an absolutely
accurate color rendering, it should give you a good idea of
the concept of the Munsell Color System and the shape of the
color spaces.The indication for a single color is expressed
by hue, value and chroma, in that order. For instance, we
use an indication like 5R4/14 to accurately transfer data
about color.
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| PCCS
[ Practical Color Co-ordinate System ] |
PCCS
is a color system made public in 1964 by Japan Color Research
Institute, who developed it as a color system to put in practice
its new color co-ordinate theory, derived from over 10 years
of study and research on color harmony.
It has greatly contributed to the education and practice of
color harmony in beaux-arts and designing, and is recognized
as a color system of Japanese origin.
This system is composed of three separate parameters of color
perception, namely, hue, value and chroma, and is characterized
by its capacity to be used functionally as a hue/tone, two-dimensional
system.
Both
the Munsell Color System and the NCS are difficult to indicate
because colors are represented three-dimensionally, adding further
complexity to the study of colors. In the case of PCCS, it has
the advantage of enabling the user to intuitively understand
the representation of color.
Tone
is a compound concept of value and chroma, and indicates the
ﾒtone of colorﾓ such as bright or dark, strong or weak. By
representing the tone of colors through the use of adjectives,
systematic naming of colors is facilitated, thereby enabling
the user to familiarize more easily.
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As indicated in the diagram, tones are separated into 12 chromatic
colors and 3 achromatic colors, which are codified.
The hues in the PCCS are basically made of 8 colors including
psychological four primary colors, red, yellow, green and
blue, and their four complimentary colors (afterimages) plus
four in-between colors with the same degree of difference.
Between these 12 colors, further colors are added to compose
a hue circle of a total of 24 colors. In this hue circle,
the three optical primary colors and colors close to the three
primary colors of color materials are included. The number
24 is a measure of 2 and 3, convenient for the arrangement
of colors.
The Munsell value system is used to indicate value in the
PCCS, with a 0.5 scale indicator, indicating 9.5, 9.0, 8.5....
Chroma in the PCCS introduces the concept of saturation, adopting
chroma of 11 levels, with the maximum set at chroma 10s as
a virtual pure color common to all hues. This is a distinct
feature not found in the Munsell color system.
Color in the PCCS is represented by combining the hue number
from 1 to 24 and the tone in abbreviated letters, v2 (vivid
red), dk16 (dark greenish blue) are examples of the two-characteristic
(hue/tone) representation. In the world of color coordination,
it is important that the combination of coloring is kept simple
and can easily convey the image.
While the Munsell Color System possesses an analogue continuity,
PCCS is digital, which fact makes this representation system
not only distinct, but also a more modern system suitable
to the present age.
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| Ostwald
System
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Ostwald
System was developed by the German scientist Wilhelm Ostwald
(1853-1932) who is regarded as one of the fathers of modern
physical chemistry. Introduced in 1923, Ostwald System succeeded
in further systematizing both psychologically and physically
the study of color.
According to Ostwald System, the color of an object is made
up of pure color along with white and black. Then, with respect
to red, yellow, green and blue, an imaginary full color is assumed.
The four colors; red, yellow, sea green and blue form two complementary
sets. (This arrangement is such that mixing of the complementary
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Psychologically, these four colors function as primary colors.
These four colors are arranged into four equal sections on
a circle, each of which is further divided into two equal
sections thereby increasing the number of colors to eight.
Spaces between each color are then divided into three equal
parts to yield a hue circle with a total of 24 hues (hues
1-24). The equilateral triangle formed by connecting points
from the pure color, black and white categories is known as
a monochromatic triangle. The space surrounded by 24 equilateral
triangles mainly along the black and white axes is known as
the Ostwald color solid.
In this color system, at intervals along the white to black
scale, fifteen achromatic colors with white and black content
are arranged. These are labeled as 'a' through 'p'(with 'j'
excluded). In the interval corresponding to pure color, 'pa'
and either 'a' or 'p', an additional fifteen achromatic colors
are also arranged. Finally, at the intersecting points of
each monochromatic triangle 105 chromatic colors are arranged.
As a scale which applies the logarithms's law of Weber･echner,
the perceptual content and physical stimulus values on the
achromatic color scale in Ostwald System vary logarithmically
in relation to each other. The same is true of white and black
content in the chromatic color section. Moreover, additive
mixture of white content, black content and full color content
is accomplished by rotor rotation (additive mixture of color
stimulus). Ostwald color solid and the color inside the monochromatic
triangle share either equivalent dominant wavelengths or complementary
wavelengths. Colors with the same color code number have equivalent
white, black and full color content.
This extremely high level of orderliness is one of the outstanding
features of Ostwald System.
In terms of color design, Ostwald System offers the convenience
of producing mechanical color harmony. To this end, the Container
Corporation of America has published the Color Harmony Manual
which establishes a color standard composed of sets of one
hue 28 colors. The Manual is widely used in the design field.
The color solid discussed above is shown in simplified form.
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| NCS-Natural
Color System |
"Natural
Color System"(NCS) was presented by Sweden Color Center
at the occasion of the First AIC (Association Internationale
de la Couleur) Congress, held in Stockholm in June of 1969.
The outline of this presentation is introduced in the first
issue of the organ of Color Planning Center, "Color Communication,"
of October of the same year (written by MINATO Sachie).
NCS is a standardized abstract system which expresses perception,
and is based on psychological primary colors in accordance with
E. Heringﾕs opponent-color theory. Therefore, in that sense,
NCS closely resembles W. Ostwaldﾕs system. However, the fact
that Ostwald System satndardizes physical reality while NCS
standardizes psychological reality, clearly distinguishes the
two. In its attempt to indicate color appearance itself by means
of psychological expression, NCS psychometrically measures quantitative
color perception to compose and indicate color notation by a
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The notation is made not of hues deriving from pigments or a
Maxwellﾕs color disc. The criterion for judgement is the colors
learnt by the heart since oneﾕs childhood. As the naming with
the word ﾒNaturalﾓ suggests, color which are naturally felt
and seen are inscribed and therefore, the color notation changes
with the variation in lighting conditions and or other conditions
under which an object is seen, through within the same color
chart. NCS expresses color appearance by the degree of perception
of the six psychological base colors. The six are yellow, red,
blue, green, white and black. These are six colors which have
made impressions on the heart, and are called basic colors.
In-between colors are indicated by the psychological ratio of
the two basic colors involved. In this case, a color cannot
simultaneously have a tincture of yellow and a tincture of blue,
and the same applies to colors between red and green.
Therefore, a color would carry a maximum of four basic attributes
belonging to two chromatic elementary colors, plus white and
black. Furthermore, a color has three different characteristics,
a tincture of chromatic colors, and tints of white and black,
with the total, numerically indicated, as 100. A tincture is
indicated by the percentage of the two chromatic colors. Color
notation is expressed in the order of the percentage of blackishness,
that of tincture, and finally, of chromatic elementary colors.
Because whiteness can be sought simply by subtracting the percentage
of blackishness and the percentage of tinctures from 100, it
is not included in the color notation. As an example, a chromatic
colorﾕs notation of ﾒ3050R40Bﾓ signifies that the amount of
black tint is 30%, and that of primary color tincture is 50%
(thus, the amount of white tint would be 20%), and that the
tincture is a color that is 40/100 closer to blue and away from
red (thus, the amount of red tincture is 60%). Another way of
expressing this particular color is that it is a color that
is perceived as being blakishness 30% + reddishness 30% + bluishness
20% + whiteness 20%.
NCS is published in the form of a Colour atlas (SS 01 91 02)
by the Swedish Standard Institution. NCS is applicable to colors
of an objectﾕs surface, but due to its nature as psychological
system, its color atlas can be used as a proper color sample
only under prescribed lighting and observation conditions.
Furthermore, it is said that the use of NCS as an emotional
space model, has spread widely among designers, architects and
those engaged in painting in the Scandinavian countries and
other parts of the world. Colors are easily imaginable from
symbols, and inversely, symbolization can be accomplished without
difficulty at the sight of colors, facilitating the explanation
of various perceptive phenomena. But on the other hand, NCS
also has its shortcomings: it does not offer a uniform perceptual
color space, has theoretically no physical standard for objects,
and is incompatible with device-oriented color measurement.
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| ABC
Tone System --- Handicraft of the Color Solid |
The
three dimensions of color could indicate the surface color of
an object precisely. The three dimensions mentioned here specify
the hue, value and chroma. However, on the scenes where color
schemes are instructed or in the fields of fashion or designs
the properties that combine value and chroma are often called
value/chroma tone so that the technique of specifying the hue
and tone by two dimensions is prevalent. This is due to the
effect of making it easier to handle and understand colors by
expressing the three dimensionally distributed colors in plane
definition.
The Tone System is the color grouping system and therefore,
various kinds of categorical systems could exist according to
the position of handling the colors.
In Japan, the Systematic Color Name Chart regulated in the JIS
Z8102 ﾒNames of non-luminous object coloursﾓ and the PCCS (Practical
Color Co-ordinate System) are widely used. There is the ISCC-NBS
Color Name Chart in the U.S.A.
The ABC (Address Book of Color) Tone System (originated by Professor
KITABATAKE Akira of Bunka Womenﾕs University) is the latest
tone system and was initially introduced into the world through
the adoption into the 1999 edition of the Japan Paint Manufacturers
Association Standard Paint Colors. This tone system is estimated
to rise swiftly to fame coupled with the wide distribution of
this book.
Much importance was attached to the color distribution in industrial
paint or materials for fashion/interior decoration so that the
ABC Tone System established the off neutral area between the
achromatic and chromatic colors. According to this system, the
achromatic colors between white and black were classified into
5 tones and the chromatic colors were classified into 19 tones.
Added to which, the color chart system of the Japan Paint Manufacturers
Association Standard Paint Colors was combined to give birth
to a color order system that places importance on practicality.
The color solid is a tool produced to communicate visually and
to understand at a glance that the color system is constructed
in the form of three-dimensional solid color space.
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| 7
Colors Printing System Designer's Color Atlas [ DCA ] |
Designerﾕs
Color Atlas is a color system for the reproduction of colors
in printing.
Color reproduction in printing progresses through what is called
a 4 colors process printing method, and most print items are
printed through this method. Theoretically, the 4 colors process
printing method of cyan, magenta, yellow and black colors produces
little defects. However, at the moment, the purity of the printing
ink color is lower than the theoretical value, resulting in
color domains that cannot be reproduced. This is seen as an
inevitable phenomenon and for luxury print items, special colors
are used to make up for this inadequacy or the 6 colors printing
system with the addition of pale magenta and pale cyan is being
used.
7 Colors Printing System was conceived as a color reproduction
method in printing to supplement the above shortcoming. It has
been made into a color sample book titled Designerﾕs Color Atlas
(DCA), and has become a color order system.
This 7 Colors Printing System uses primary ink colors of cyan,
magenta, yellow and black which are used in the 4 colors process
printing system and additional 3 colors of orange, green and
violet.In this 7 Colors Printing System, color is reproduced
by layer-printing the 2 colors which are next to each other
in the hue circle of the 6 chromatic primary colors or by combining
the aforementioned 6 colors with black. To reproduce colors
in printing, a highly transparent printing ink is used. |
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The density of the ink that is transferred onto the paper
is adjusted by changing the dot dimensions or depth of plate
and reproducing the target color through pointillism mixture
and subtraction mixture in layer-printing. A color with a
high degree of chroma particularly needs to have large dot
dimensions, so it is mostly the subtraction mixture that is
employed. The decrease in chroma accelerates with the increase
in hue disagreement between the primary ink colors.
Thus, in a 4 colors process printing system, the performance
of color reproduction deteriorates in the orange, green and
violet color domains. 7 Colors Printing System was developed
as a solution to this shortcoming.
The structure of the color dimension in a 7 Colors Printing
System is one that was derived from combining a star-shaped
plane of 6 primary colors that were arranged into 6 points
as shown in the illustration and an equal dot-surface of black
ink, etc. or in other words, equal black content surface.
Itﾕs in the shape of a star consisting of 6-angled reverse
pyramids whose peak is the 0% black ink dot surface and that
converges on a single point of 100% black ink.
A psychological observation of the position-relationships
between these 6 chromatic primary colors in the hue circle
shows that the colors were arranged with equal space between
them, the 3 colors of cyan, magenta and yellow, standard Japan
colors, are used as is, each color ink is of high-degree transparency
and the 3 colors that are positioned in the middle were established
under the condition of having similar density and such. The
differences in angle between each primary color are represented
on the Munsell hue circle as follows: 50 degrees between magenta
and orange, 75 degrees between orange and yellow, 85 degrees
between yellow and green, 55 degrees between green and cyan,
45 degrees between cyan and violet and 50 degrees between
violet and magenta.
For color printing using a dot screen, 4 types of screen angles
were established to avoid the moir? phenomenon: 15 degrees,
45 degrees, 75 degrees and 90 degrees. Each of the angles
were fitted to a color. Thus 4 angles is seen to be the limit.
In 7 colors printing, it is possible to avoid the moir? phenomenon
since the 2 colors on the opposing angular lines do not co-exist
in any small domain. Thus, the same screen angle can be established
for the 2 colors on the opposing angular line.
The patent to this 7 Colors Printing System is owned by Dainichiseika
Color & Chemicals as ﾒa printing method that is outstanding
for the color reproduction of high degree chroma.ﾓ
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