The physical aspects of a theory of colour vision / by F.W. Edridge-Green.

  • Fredrick William Edridge-Green
Date:
[1902?]
Catalogue details

Licence: In copyright

Credit: The physical aspects of a theory of colour vision / by F.W. Edridge-Green. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

    4/8
    2 defect in the perception of colour. In the first class certain rays are either not perceived at all or very imperfectly. Both these classes are represented by analogous conditions in the perception of sounds. The first class of the colour- blind is represented by those who are unable to hear very high or very low notes. The second class of the colour-blind is represented hy those who possess what is commonly called a defective musical ear. Colour-blind individuals belon^ng to this class can be arranged in a series. At one end of this series are the normal sighted, and at the other the totally colour-blind. The colours appenr at the points of greatest diff'erence, and I have classified the colour-blmd in accordance with the number of colours which they see in the spectrum. If the normal sighted be designated hexachromic, those who see five colours may be called pentachromic ; those who see four, tetrachromic ; those who see three, trichromic ; those who see two, dichromic; and the totally colour-blind, monochromic. There are many degrees included in the dichromic class. There may or may not be a neutral band, and this is widest in those cases approaching most nearly to total colour-blindness. I have recorded a case of a patient who was colour-blind with one eye. It is an interesting fact that for form vision the colour-blmd eye was much the better of the two, and he could recognise fine lines in the spectrum with this eve which were not visible to the other. He saw the two .ends oi the spec- trum tinged with colour and the remainder grey. It will be noticed that his colour sensations were limited to the extreme red and the extreme violet, namely, those colours which present the greatest physical contrast to each other. Neither the red nor the violet appeared of the nature of a primary colour, but gave the impression that they were largely diluted with grey. A theory of colour vision must account for a case of this kind and also for the other varieties and degrees of colour-blindness. The trichromic are a very important class, and any theory must account for the fact that they see yellow as red-green and blue as violet- ereen. As we should theoretically expect, when there is shortening ot the soectrum the centres of the colours are moved towards the unshortened side. ^ I ^Tl conclude by showing how this theory will explam the tnchroma ism of norm^colour vision It also explains why certain persons see spectral yeUow as red CTeen and spectral blue as green-violet. In past ages all saw the rainbow made up of only tS^^^^^^^^^ red, freen, and violet. When a new colour appeared between the red and green (yellow) it is obvious that a mixture of red and green woTd give rise! not to red-^een, but to the colour which had replaced it, namely, yellow. PRINTED nv SP0TTI9W00DE AND CO. LTD., NEW-8TEEBT SQUAKK LONDOK
    No text description is available for this image
    No text description is available for this image
    No text description is available for this image