Color Model
A mathematical framework for representing colors as numerical values. Multiple models such as RGB, CMYK, and HSV exist for different applications in digital imaging and print.
A color model is a mathematical system describing colors as ordered tuples of numbers. Each model defines a coordinate space with three or four axes (channels), where every point corresponds to a specific color. Image processing workflows routinely convert between models.
- Additive models (RGB): Combine red, green, and blue light. This mirrors how displays emit light and cameras capture it, making RGB the default for screens and video
- Subtractive models (CMYK): Use cyan, magenta, yellow, and black inks that absorb light on paper. Commercial printing relies on CMYK because inks subtract wavelengths from reflected light
- Perceptual models (HSV / HSL): Organize color along hue, saturation, and value axes that align with human intuition. Color pickers in editors expose these axes for intuitive manipulation
- Uniform color spaces (Lab): Engineered so that Euclidean distance correlates with perceived color difference. Lab serves as the Profile Connection Space in ICC color management
Converting between models involves matrix multiplications and nonlinear transfer functions. For example, transforming sRGB to Lab requires inverse gamma correction to linear RGB, a matrix multiply into CIE XYZ, and a cube-root transformation into Lab. When source colors fall outside the destination gamut, clipping or gamut mapping algorithms remap them to reproducible colors.