CIELABmallilla

CIELABmallilla is a hypothetical extension of the CIELAB color space that adds a fourth dimension aimed at capturing the influence of surface microstructure and material reflectance on perceived color. While CIELAB provides perceptual uniformity for many color pairs, CIELABmallilla seeks to address metamerism and texture effects that vary with illumination and viewing geometry. The term appears in speculative discussions and experimental datasets and is not an established standard.

In CIELABmallilla, a color is described by (L*, a*, b*, M), where L*, a*, b* are the standard CIELAB coordinates and M is the mallilla coordinate representing microstructure response. The transformation uses a Mallilla operator that maps measured reflectance spectra, surface texture metrics, and illuminant data to M through a monotone function designed to preserve perceptual ordering. The a*, b* components may be adjusted by M to produce a four-dimensional perceptual space; practical implementations often rely on 4D LUTs or neural networks to translate device colors to the mallilla space under given viewing conditions.

Calibration requires multi-illuminant, multi-texture datasets and standardized procedures to measure texture-dependent color shifts. Applications are proposed for high-precision color matching in 3D printing, digital textiles, and archival visualization where surface finish materially affects color perception.

Limitations include lack of standardization, increased computational and data requirements, and limited interoperability with existing color-management workflows. As a result, CIELABmallilla remains primarily of theoretical or exploratory interest rather than widespread practice.