Color matching systems

Table of Contents

Color spaces and international color standards

The color model

Color shades are distinguished by their spectral composition. To define and standardize these differences, various color models have been developed.

The colors of a color model that a particular coloring process is capable of outputting are displayed in a color space. Because the coloring methods are different in the ability to output or display colors, the respective color space is different.

For the representation of the actually abstract color system, the three-dimensional form is usually chosen for the color model. Within these spatial models, the individual nuances are assigned to unique values, the color locations. The representation of all color locations of a color model forms the color body.

The color locations

The color location is a specific point in the color body that represents a single color nuance. Its position in the color space is described by means of coordinates.

To set the color location, three parameters are needed. The characteristics of the parameters are different depending on the color model. Thus, one of the color models for spatial determination uses the values ​​of brightness, saturation, and hue. Other color models use the parameters light/dark, red/green and yellow/blue.

The following three values ​​determine the position of a hue in the color space:

  1. Saturation (position on the horizontal coordinate axis)
  2. Brightness (position on the vertical coordinate axis)
  3. Color (position on the applicate axis)

The color space

In all coloring processes, inaccuracies and losses occur in the conversion and representation of the colors. Although colors may have a defined color location, they can not be reproduced with the colorants specified by the conversion process.

The representable colors form a body within the color model, which is also referred to as Gamut. This body is called color space. In the ideal case, the color space fills the entire color model. The color space of a coloring process includes all colors that can be displayed within the color model.

The representation of color spaces is often realized by abstract topographical descriptions. An alternative to this are color samples in a color catalog. However, as already mentioned, there are deficiencies in the representation of the colors due to the conversion process

The color catalogs

In practice, color catalogs, color registers or color collections that consist of standardized reference color samples enable precise communication between manufacturers and customers.
Color catalogs are usually made available in the form of printed or coated papers, the colors of which are named according to an exclusive and/or international color standard. In order to convey a realistic impression of the color effect depending on the use and to include properties such as surface structure, color depth or gloss degree in the evaluation, reference colors are also produced in the form of material samples.

In the color plans offered in the store, all listed nuances are provided with the codes of the following international color standards:

RGB Color space

RGB color spaces are used as the basis for the representation of colors with CRT and TFT displays or projectors. The color is performed through the additive mixing of three primary colors (red, green and blue).

RGB Color model

The sRGB Color space

Figure 1: The sRGB Color space (resolved to 5832 colors)

HLC Color space

The more easy to read coordinates of the CIELAB color space: HLC is the short form of hue, lightness and chroma. This color notation is used in specific software and in some paint color matching systems.

LAB Color space

The HLC Color space

Figure 2: The HLC Color space (resolved to 4326 colors)

RAL Colors

RAL is an internationally used color matching system with several product lines: Two of the product lines are the RAL Classic system with 210 colors and the RAL Design system with 1625 colors. The numbering if the color shades in RAL Design follows the scheme based on the HLC color space.

RAL Colors

The Color space of the *RAL Classic* system with 213 colors

Figure 3: The Color space of the RAL Classic system (213 colors)

The Color space of the *RAL Design* system with 1625 colors

Figure 4: The Color space of the RAL Design system (1625 colors)

Munsell Color

The Munsell color system was created in the first decade of the 20th century is based in human visual perception. The Munsell system with its 1488 color tones is in wide use today, especially in USA and Japan.

Munsell Color

The Color space of the *Munsell Color* system with 1488 colors

Figure 5: The Color space of the Munsell Color system (1488 colors)

NCS Natural Color System

The NCS is a color model with 1952 color tones published by the Scandinavian Color Institute. It is internationally used in the corporate, manufacturing and coating sector.

NCS

The *NCS* Color space with 1952 colors

Figure 6: The NCS Color space (1952 colors)

British Standards

A set of 5 color fans, representing totally 1033 color tones, used for industrial and building purposes in the United Kingdom.

BSI Group

The Color space of the *British Standard Colours* with 479 colors

Figure 7: The Color space of the British Standard Colours (479 colors)

The Color space of the *British Standard 4800F* with 120 colors

Figure 8: The Color space of the British Standard 4800F (120 colors)

The Color space of the *British Standard 5252F* with 240 colors

Figure 9: The Color space of the British Standard 5252F (240 colors)

The Color space of the *British Standard Buildings and Decorative Paints* with 101 colors

Figure 10: The Color space of the British Standard Buildings and Decorative Paints (101 colors)

The Color space of the *British Standard Readymixed Colors* with 93 colors

Figure 11: The Color space of the British Standard Readymixed Colors (93 colors)

JPMA Standard Paint Colors

Standard colors fan of the Japan Paint Manufacturers Association representing 656 color tones and therefor widely used in Japan.

Japan Paint Manufacturers Association

The Color space of *JPMA Standard Paint Colors* with 656 colors

Figure 12: The Color space of JPMA Standard Paint Colors (656 colors)

CBCC China Building Color Card

The color card of the building trades with 1026 color tones. It is the standard tool of architecture colors register, communication, and management in China. The color naming takes place in hue, value and chroma and is somewhat cryptic. However, in addition, all listed shades are consecutively numbered. That greatly simplifies the work with the China building color card.

CBCC China Building Color Card

Color space of the *China Building Color Card* with 1026 colors

Figure 13: Color space of the China Building Color Card (1026 colors)

Author: Paul Zoller, studio@farbica.com

Date:

Emacs 27.2 (Org mode 9.4.4)