Colour : a text-book of modern chromatics with applications to art and industry (1904)
Rood, Ogden N. (Ogden Nicholas), 1831-1902 · London : Kegan Paul, Trench, Trübner · leaf 47
THE CONSTANTS OF COLOUR. 37 small portion of the spectrum. This object is easily at- tained by introducing into the eye-piece of the instrument … a diaphragm perforated by a very narrow slit (see Fig. 9). The observer then sees in the upper part of the field of view the selected spectral colour ; in the lower part of the field the scale is visible, and with its aid the precise position of the prismatic hue can be determined. Instead of using…
Color
Internet Archive · Wellcome Library · Public domain (published before 1931). Free to use for anything.
