Originally, a judgement of the amount of light
reflected to the eye from the surface of a
material, regardless of hue or color saturation.
Brightness is now measured by optical comparators.
Many factors affect the brightness of a material
such as paper, including the degree of bleaching
of the pulp, as well as the addition of chemicals.
Chemically treated high-grade text and book papers
have a brightness in the range of about 96 (on a
scale of 100), coated papers range from about 70
to 85, while mechanical wood machine-coated papers
are in the range of about 60 to 75. Newsprint is
generally below 60. (17 , 72 )