Researches in Colour Vision and the Trichromatic Theory (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1913 Excerpt: ...of the rays transmitted to the eye were 96'5 and 21 '5 respectively. The colour field for each of these four colours was taken with the left eye, and the following table shows the results (Fig. 70): --Here we have two fields, the green and the blue, which are practically identical, showing that the limits of the boundaries are not affected by the hue, though, of course, the illumination is very different in the two cases. Fields of Impure or Mixed Colours. When considering the question of the fields of mixed colours, such as those produced by pigments, it became apparent that a crucial test as to their efficiency might be made by mixing colours of the spectrum together to imitate some single spectrum colour, and, after making the mixture of the same luminosity, to compare the fields. With this in view, a red and green, near E, were mixed together to match the D light in hue and in intensity. The fields for each colour, including D, were taken, as also was that of the mixed colours. The following table gives the results: --Table XXX. These colour fields all have the same shape (Fig. 71). They do not cut one another, and if we compare the Fig. 71. fields of the red and the green with those of the green and the blue in the previous table, we shall see that they practically coincide. Thus the fields of a red, two greens, and a blue are the same when proper luminosities are taken for each. Before leaving this table, it is well to point out that the field for D is considerably more extended than that of the mixed colours, as are also the fields for green and red separately. We may conclude that the intrinsic white light in each colour, when added together, is greater than the intrinsic white light in the D ray, which has been shown to be the case in the chapter on ...