a visual attribute of things that results from the light they emit or transmit or reflect

interest and variety and intensity

the timbre of a musical sound

an outward or token appearance or form that is deliberately misleading

any material used for its color

(physics) the characteristic of quarks that determines their role in the strong interaction

the appearance of objects (or light sources) described in terms of a person's perception of their hue and lightness (or brightness) and saturation