ABSTRACT
Materials that reflect light uniformly through the visible spectrum appear neutral, that is white, grey or black depending on the reflectance. A reflectance of 1 indicates that 100 per cent of the light is reflected, and the object appears perfectly white. Conversely, a zero reflectance indicates a perfect black. A reflectance of 0.20 corresponds to a mid-grey tone reflecting 20 per cent of the incident light. However, equal visual steps between black and white are not represented by equal steps in reflectance.
