CIELABia

CIELABia is a fictional or hypothetical color model that extends the established CIELAB color space by adding perceptual and contextual dimensions. It is described in speculative color science discussions as a way to bridge color specification with material appearance and lighting context, without claiming real-world adoption.

Concept and structure: In CIELABia, the base coordinates L*, a*, and b* are retained to encode lightness and chroma in a perceptually uniform manner. Two auxiliary axes are introduced: M for material appearance (such as surface finish from matte to glossy) and I for illuminant adaptation (how colors shift under different lighting). A color in CIELABia is conceptually represented as (L*, a*, b*, M, I), allowing simultaneous consideration of color, surface properties, and lighting.

Relation to CIELAB: CIELABia builds on the idea of perceptual uniformity central to CIELAB but acknowledges that a single color representation often fails to predict appearance across materials and illuminants. By including material and illuminant context, CIELABia aims to provide a more holistic description of how a color looks in practice, while keeping the original L*a*b* components recognizable for backward compatibility in theory.

Evaluation and usage: The concept is used mainly for pedagogy, visualization, and early-stage design prototyping in hypothetical workflows. It is not a standardized or widely supported system, and real-world implementation would require extensive perceptual calibration, material reflectance data, and robust methods for converting between CIELABia and conventional color spaces. Metamerism and cross-material comparisons remain challenging within any extended model.

Notes: As a fictional construct, CIELABia serves to illustrate how color appearance modeling could be expanded to include context. It is not an official standard and lacks formal specifications or measurements.