Farbwahrnehmungsunfähigkeit

Farbwahrnehmung, or color perception, is the visual system's ability to interpret the spectral content of light as color. It arises from the retina's photoreceptors and higher-level brain processing, enabling discrimination among millions of colors under varying lighting.

The retina contains rods and cones, with humans typically having three cone types sensitive to short, medium, and long wavelengths—roughly blue, green, and red. The initial encoding is trichromatic: color information is carried by the relative activation of these three cone types. This stage explains how different wavelengths mix to produce a broad range of hues.

Beyond the initial encoding, the brain uses opponent-process mechanisms to form color experiences in red–green, blue–yellow, and black–white channels. The trichromatic theory accounts for hue detection at the receptor level, while the opponent-process theory explains post-receptoral processing and many perceptual phenomena. Together, they describe how color signals are represented and interpreted along visual pathways.

Perception remains relatively stable under changes in lighting due to chromatic adaptation and color constancy, aided by contextual cues and prior experience. Standardized color representations, such as the CIE 1931 XYZ color space and sRGB, are used to measure and reproduce colors across devices and contexts. Individual perception can vary with lighting, age, and other factors, including color vision deficiencies.

Color vision deficiencies affect a portion of the population, most commonly red–green impairments (protanopia, deuteranopia) and less commonly blue–yellow impairments (tritanopia). In history, the complementary theories of Young–Helmholtz and Hering helped establish the dual aspects of color processing that underpin modern understanding.