The influence of specular reflectance, albedo, and shape on perceived gloss: A case for three-dimensional maximum likelihood conjoint measurement (MLCM).

Abstract

Gloss perception depends on several surface properties, but most studies measure these effects only one or two at a time. Here, we test whether a three-dimensional version of maximum likelihood conjoint measurement (3D-MLCM) can be used to capture the combined influence of multiple cues on gloss. Observers judged which of two surfaces looked glossier while specular reflectance, albedo, and bumpiness were varied together. The additive model showed clear and reliable contributions of both albedo and bumpiness in addition to specular reflectance, and model comparisons confirmed that these cues significantly affected gloss judgments. The full model further revealed that these effects change with gloss level: bumpiness strongly influenced perceived gloss at low specular reflectance but had little effect at high gloss levels. These results show that 3D-MLCM provides stable, interpretable measurements and is a practical method for studying complex interactions between visual features that influence visual appearance.