What is CIE-LAB?
Also known as: LAB color space, CIELAB
A color space designed to match human visual perception, where Euclidean distance approximates perceived color difference. The standard workspace for professional color matching in textiles.
In detail
CIE-LAB (also written CIELAB or just 'LAB') is a perceptually uniform color space defined by the International Commission on Illumination in 1976. Its three axes are: L* (lightness, 0-100), a* (green-red, -128 to +127), and b* (blue-yellow, -128 to +127). The defining property is perceptual uniformity — equal Euclidean distances in LAB space correspond to roughly equal perceived color differences. This makes it the natural workspace for color matching algorithms (k-means clustering, Delta E calculation, gradient analysis) because the math actually corresponds to what the eye sees. RGB and CMYK are device-dependent and non-uniform; LAB is device-independent and uniform. Professional textile color workflows convert to LAB for analysis and back to RGB or CMYK only for display or production output.
Example
A k-means color separation clusters 2 million pixels in LAB space. Two cluster centroids at L*60 a*30 b*-10 and L*62 a*32 b*-12 are perceptually almost identical (Delta E ~3) — the separation algorithm merges them into one channel rather than producing two visibly identical clusters.