A system is described whereby just noticeable differences in gloss can be expressed in terms of differences in specular luminance factors. The number of just noticeable gloss differences was determined graphically for paint specimens with specular luminance factors varying from 0.5 to 40.0. For the specification of gloss a system is proposed in which gloss units are equivalent to just noticeable gloss differences.
M. C. BOSHOFF, "Gloss Scale for Paint Surfaces," J. Opt. Soc. Am. 48, 741-744 (1958)