body paint
Body color (also object color ) is the color of a non-self-luminous object, i.e. a body that requires illuminating radiation to make it visible. It is the color stimulus emanating from objects (solid, liquid, gaseous) that transmit or reflect ambient light. In contrast, light color is the color of a self-illuminating light source .
Physical description
Body colors change the spectral composition according to their transmission and remission behavior. For practical reasons, a distinction is made between transparent colors (colored solutions, color filters) and non-transparent colors (paint, textile coloring). The former are described by the spectral transmittance τ λ , the others by the spectral reflectance β λ .
The color impression is created by reflecting the incident light and changing its spectral composition. Two properties of the body work here: on the one hand, the coloration ( pigmentation ) influences the absorption of light due to the specific electron configurations, and on the other hand, the light scattering that occurs due to the surface properties of the body . The scattering is caused both by macroscopic particles and by quantum mechanical effects.
The colorimetric approach for the value description of body color - i.e. between substrate, dye and body surface - comes from Kubelka and Munk . This creates a connection between the concentration-dependent absorption coefficient K, a substance-specific scatter coefficient S and the reflectance β (λ). This relationship is a function of wavelength ; H. spectrally dependent. Differential components of the incident light are scattered in differential layers near the surface and a proportion of the absorbed light is again scattered at the next layer. The physical property is given as a remission factor β (λ) spectrally as a function of the wavelength. The perception is still influenced by the prevailing lighting (type of light, white point ), which is also included in the effect as spectrum S (λ).
transparency
The transparency color (see-through color ), which is perceived by transparent or translucent bodies, can act as a light color under certain conditions . The transmittance τ (λ) is used for the spectral composition. If there is no scatter, this spectrum can be used according to Lambert and Beer to determine the concentration.
Color mixing
Subtractive color mixing can be applied to body colors . The actual visual quality (the light color ) follows reflection and scattering of the additive color mixture .
See also
Individual evidence
- ↑ a b DIN 5033-1 . In: German Institute for Standardization e. V. (Ed.): Colorants 1 . 7th edition. DIN-Taschenbuch 49.Berlin, Vienna, Zurich 2012, ISBN 978-3-410-23202-5 , pp. 6 .
- ↑ DIN 55943 . In: German Institute for Standardization e. V. (Ed.): Colorants 1 . 7th edition. DIN-Taschenbuch 49.Berlin, Vienna, Zurich 2012, ISBN 978-3-410-23202-5 , pp. 512 .