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THE RELATION OF WAVE‐LENGTH AND LIGHT INTENSITY TO COLOUR DISCRIMINATION IN NORMAL AND HYPOCHROMATIC (COLOUR BLIND) INDIVIDUALS
Author(s) -
Roaf H. E.
Publication year - 1927
Publication title -
quarterly journal of experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0370-2901
DOI - 10.1113/expphysiol.1927.sp000399
Subject(s) - brightness , wavelength , maxima , mathematics , optics , intensity (physics) , statistics , physics , art , art history , performance art
1. Normal colour vision is characterised by the existence of two critical regions about the wave‐lengths of 5800 Å and 4900 Å respectively. These two regions are indicated by maxima of discriminating power and by a uniform colour with differences in brightness. 2. The well‐marked cases of hypochromatism that have been examined lack the power of discriminating between the colours bordering on the yellow, but they are extremely sensitive to differences in wavelength at about 4900 Å. There is no maximum in the region about 5800 A, and mistakes may be made over a range extending from at least 6500 A to 5500 Å. 3. In order to compensate for lack of discrimination of the longer wave‐lengths, hypochromats make use of differences in brightness. It is probable that another factor is necessary to explain how they distinguish between red and green, and it is suggested that the power of discrimination between blue and the rest of the spectrum may help in such colour judgments. 4. A comparison has been made between the various parts of the spectrum and the colours produced by recombining the remainder after progressive cutting off of the red and violet ends respectively of the spectrum. The expenses of this research were defrayed by a grant from the London Hospital AMedical College Research Fund.