The article solves the color description problem
Everything has a color.
Objects have the ability to absorb, reflect and transmit light at different wavelengths, which reflects a part of the light into the human eye and forms colors after brain processing. Thus, hundreds of millions of objective objects, illuminated by light, constitute a colorful world.
In the stage of tooth and tooth learning, we are often taught by our elders to recognize colors, red, orange, yellow, green, blue, purple, and so on, and we think that this is all. Too young too naive！ Growing up, whether it is the endless color numbers in beauty shops, the variety of gemstones in jewelry stores, or the objective description of the subject of the study, you have made another difficulty: obviously it is all red, why is it different?
Not very good look emm
Rutter et al., 1991
It seems to be all brown, and it seems to be a little different
Obviously, it is impossible to objectively and accurately describe colors with colloquial adjectives, let alone communicate and discuss. Some people think of distinguishing colors by codes and numerical units, the so-called "color system".
Before talking about the color system, we must first clarify a few concepts:
Lightness is the embodiment of the degree of color light and darkness, specifically, the highest brightness is white, and the lowest brightness is black. This concept depends on the degree of illumination of the object and the ability of surface reflection.
Saturation, also known as purity, is a representation of how vivid a color is. For example, now there is a cup of solution containing red dye, we continue to add water to the solution, you can see the color is slowly becoming lighter and lighter, which is the visual embodiment of the gradual decline in saturation (purity).
From the outside to the inside, the purity gradually decreases
Color system and color stereoscopic: According to the characteristics of different brightness, hue, and purity, thousands of colors are arranged according to the law and order of the fixed, and named, which is called the color system. The color system expresses the relationship between these attributes with the help of three-dimensional space, that is, the color stereoscopic. The image is a little, the color stereoscopic is similar to the earth, the poles generally represent the brightness, the equator is the embodiment of the hue ring, and from the core - mantle - crust process, the greater the degree of color saturation, that is, the greater the purity.
Hue ring: The colors of the hue are arranged in a ring in order. The role in the color system can be understood as the basic color library of the system.
Four common hue rings
At present, the commonly used color systems mainly include the Ostwald color system in Germany, the NCS color system of the Swedish color center, the Munsell color system in the United States and the P.C.C.S (Practical Color co-ordinate System) color system of the Japanese Color Research Institute.
From Qian Huang & Feihu Chen, 2019
Ostwald, as a veteran color system, was published as early as 1919 by the German chemist Friedrich Wilhelm Ostwald (thermal knowledge, this Ostwald won the 1909 Nobel Prize in Chemistry for "his work on catalytic action and chemical equilibrium and reaction, as well as the method of making nitric acid from ammonia", and the "Ostwald's law of dilution" mentioned in our university chemistry is one of his masterpieces).
Twenty-four hue rings
This color system is mainly based on the painter's color grading principle, with red, green, yellow, blue and four colors a total of eight colors as the base color, and each color is divided into three equal parts and combined into twenty-four hue rings. Then, with the solid color F, black B and white W as variables to form an equilateral triangle (the proportion of color blocks on each side increases by multiples, a total of 8 levels, a, c, e, g, i, l, n, p represents a specific content of white and black, that is, chiaroscuro), as long as the value is assigned to F, B, W, and meetSW + B + F = 100 (%), the specific color can be quantitatively obtained.
The color representation symbol of this color system is "hue number + white content + black content", such as light blue 16ga: 67% (100-g-a= 67%) with a hue of 16, 22% (g) of white, and 11% of black (a). That is, the Ostwald color system's color assignment formula for color is "solid color + white + black".
Ostwald color system
Obviously, adding white/black components in proportion does not cover all colors. In other words, we can't get all-black and all-white colors—the black of this system is not all-black, but 3.5% white. White is also not all white, with 11% black. Obviously, both the color gamut and the number of colors are limited.
The chromatography of the Ostwald color system
(Take a closer look, isn't the color at full color as pure as you think?) ）
This limitation is essentially a limitation caused by an over-reliance on mathematical formulas. So, wouldn't it be better to abandon the formula and perceive it with the naked eye alone?
The Swedish Color Center adjusts the color light and dark division of the isochrome surface on the basis of the Ostwald color system, from being determined by the equation of equal proportion to being judged by the sense, called the "NCS" color system. This color system uses the color changes perceived by the person as the basis for creating a color system (the color distribution of this system looks more comfortable and gradient, precisely because it is graded by feeling and is closer to the person's perception of color).
Chromatic and other hue surfaces of the NCS color system
The color space of the NCS color system is like two cones interlocked, the top is white, the bottom end is black, and the largest cross-section of the middle circumference is a pure color ring without black and white, with yellow, red, blue, and green as the four corners, and there are 100 equal grades between the two, a total of 400 levels of hue, and every 10 steps is represented in the hue ring. With the addition of 100 levels of saturation and 100 levels of brightness, this system covers 1950 standard color cards, which is the best of all systems.
NCS system color stereoscopic
The representation of color by the NCS color system can be interpreted as follows. Take, for example, the blue color of the Swedish flag, whose NCS color number is S 4055-r95b. Among them, S indicates a reference to the second edition of the NCS, 4055 means pure black accounts for 40%, pure color accounts for 55%; as can be seen in the hue ring, R95B indicates containing 95% B (blue) + 5% R (red).
The blue color of the Swedish flag is represented by the NCS color system
S 4055-R95B
NCS hue ring
Similar to the above-mentioned Ostwald color system and NCS color system, the PCCS color system of the Japan Institute of Color Research also takes red, green, yellow and blue as the basic colors, and makes subtle adjustments in the completely symmetrical color arrangement of the NCS, filling the hue ring by determining the position of the four basic color complements, so that the color difference between the interval colors is consistent.
PCCS hue loop
The PCCS color system generally describes colors as "hue-luminous-chroma" form. For example, "8:Y-8.0-9S" means that the hue is 8Y, the brightness is 8.0, and the purity is 9S, corresponding to the color card, which should be a light yellow whose color concentration does not look low.
In addition, PCCS also put forward the concept of hue, which is a composite representation of color purity and brightness, corresponding to different psychological feelings with different shades, and is more used in industries such as the fashion industry and the color education industry that need color collocation.
PCCS shades
In fact, the most widely used is the Munsell color system. For example, soil description, gem color evaluation and other geology-related color applications are the Munsell system. Our common example is "10Y9/6", which is the 10th yellow with a brightness of 9 and a purity of 6. Obviously, the Munsell color system's color value representation is "hue number + luminosity/purity".
Munsell color system hue ring
Unlike the three systems introduced above, the Munsell system uses ten colors as the primary color, including red R, yellow Y, green G, blue B, purple P, adding intercolor YR, GY, BG, PB, and RP. Each hue is divided into 10 levels, with a total of 100 hues. However, the actual colors do not all make 10 levels of color, so the common color cards are 2.5, 5, 7.5 and 10 values of hue. In addition, the system is divided into 11 levels in brightness and 30 levels in saturation. However, due to the different degrees of light and shade of different hues, the maximum purity is also different from the center axis, so the Munsell color stereoscopic structure is asymmetrical (a total of 1737 color cards).
Chromatography of the Munsell color system and the PCCS color system
Because PCCS also borrows some of Munsell's ideas, from the perspective of color stereoscopic diagrams, the two are quite similar, and both have differences in the brightness values of different solid hues. The difference between the two is that the maximum purity value of the Munsell system in different hues is different, for example, the maximum purity value of 10YR is 14, and the maximum purity value of 2.5B hue is 8. This difference in maximum purity values is the implementation of the Munsell system based on human feelings. PCCS, on the other hand, uses the numerical value of the color as the standard, so the maximum value of the same purity value can be obtained.
The equal hue of the two color systems is not small
When using color systems, it is generally required to compare standard color cards under a specific range of light. For the judging of color, there will generally be 2-3 professionals who will independently rate it, and finally give the color rating based on the comprehensive consideration. Thinking back to the awkward look of looking for a color card when I did the assessment two or three years ago, I couldn't help but be funny.
Finally, let's review the expression of different color systems:
Knowing all this, I think you can smile at the various color questions asked by your girlfriend and have a good year (manual dog head)
(Little Angel Link: You can use this color gadget to check the color https://www.colortell.com/colorspeed)
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LIN Zhongxian. Psychology of color vision[M]. Beijing: Beijing Renmin University Press, 2011.
LI Xiaokun. Lecture on color science[M]. Guilin: Guangxi Normal University Press, 2003.
HUANG Qian,CHEN Feihu. Comparative analysis of four color systems[J].Packaging Engineering,2019,40(08):266-272.
Editor: Lu Yangyang
Proofreader: Zhang Tengfei Jiang Xuejiao