Color mixing

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In color theory, color mixing or color synthesis describes the representation of all visible colors by mixing a limited number of colorants or colored lights , the color stimulus of which is a basic color . Due to the structure of the human eye and the limited perceptible light spectrum , a convincing representation of the color succeeds without having to reproduce the original reflection spectrum .

overview

The following color mixing methods are usually distinguished from one another:

The mixture of two basic colors within one system, the so-called primary colors , results in a basic color of the other process. This in turn is called the secondary color of the original (first) system.

Example: The additive mixture of red and green results in yellow. So yellow is a secondary color of the additive color mixture and at the same time a basic color of the - subtractive - colorant mixture.

The mixture of three primary colors results in a tertiary color . Depending on the size of the individual color components, the result is an increasingly unsaturated hue . With the same proportion of all three colors, the result is achromatic , i.e. a pure gray , black or white , depending on the "initial intensity " .

Although this simple representation is sufficient for the normal case (and for many electro-optical vision devices ), one quickly reaches its limits when it comes to colors accurately recreate or for printing reproduce .

Pure colors

Pure colors are the most intense color stimuli that occur in nature. According to their nature, these are the spectral colors that form the spectral color train in the CIE diagram . Due to the nature of color production ( color valence ), only light colors can fulfill this property. From Ostwald , the concept of "was full-color " (especially) for the only theoretical construct of embossed, optimal color .

The concept of the purity of a color is also applied to colorants , i.e. body colors . It is then those colorants (colored surfaces) that form a (as far as possible) unadulterated color valence. Such (highly pure) pigments with a high depth of color are most likely to be used by the artist for color mixing, as they are suitable as primary colors .

The opposite of pure color is the broken color , of which there are many variations according to the definition, while in each system there is only one pure color.

"Mixing" the colors

Color modulation
is the mixture of a pure color with one or more colors; there is a change in the color character of the original color.
Subtractive color mixing
The subtractive color mixing is based on the principle that in the color layers of the primary subtractive colors of the light spectrum are absorbed parts. Transparent dyes in the primary colors yellow (Y), magenta (M) and cyan blue (C) act as filters by absorbing certain spectral ranges of the light. The physical basis of this form of mixture is the absorption of radiation on surfaces and the different remission based on it.
The mixing takes place on substrates with the basic color white. The basic color green is created from yellow and cyan blue on white, since the yellow color layer absorbs the short-wave components and the cyan-blue color layer absorbs the long-wave components of the (previously) remitted white light. Only the middle part of the spectrum is allowed through, so that green is perceived. Examples can be found in photography, watercolors, oil glazes, and in three- and four-color printing. In the offset printing process, all four-color images are created by mixing the filter colors cyan , magenta and yellow, as well as by adding black .
Additive color mixing
With additive color mixing , colored lights are mixed. The additive basic colors: orange-red (R), green (G) and violet-blue (B) can be found in the RGB color spaces . The achromatic basic color black must be present as the basic color (here the “before color” is meant). Examples of this are the emitting technologies: television , monitor . The physical basis of this hybrid form is the outgoing emission of radiation of different spectral forms.
Integrated color mixing
For opaque colorants (according to Küppers ) the “law of integrated color mixing ” applies . Not only three primary colors are sufficient to work together by “mixing”. Rather, all eight basic colors (white, orange-red, yellow, green, cyan-blue, violet-blue, magenta-red and black) must be available as primary colors for new colors. The law of the integrated mixture applies to opaque colorants such as tempera paints “gouache”, colored lacquers, acrylic paints, and colored powder.

Web links

Individual evidence

  1. ↑ color modulation - entry in encyclo ; As of March 20, 2011.
  2. ↑ Harald Küppers: Color - Origin, Systematics, Application . Callwey Verlag, Munich. 4th edition 1987. ISBN 3-7667-0855-4 .
  3. ↑ Rainer Klinke et al., Physiologie , 5th edition, Thieme Verlag 2005, ISBN 3-13-796005-3 .