IN 1948 the German physicist, Manfred Richter, reported that colour vision has a seasonal variation1,2. For four colour-normal subjects, he found a sinusoidal variation in the proportion of red and green required to match a monochromatic yellow, the equation known as the 'Rayleigh match'3. In summer, subjects required more red in their mixture. The measurements were made with the Nagel anomaloscope, an instrument introduced in 19074,5 and which today, essentially unchanged, remains the definitive clinical instrument for classifying the many phenotypic variations in colour vision. The variation that Richter recorded in the red–green ratio was large (three Nagel units), and it now takes on fresh interest because it is comparable in size to the difference in Nagel settings later reported between normal observers of different genetic types6,7. We have been able to replicate Richter's result, but report here that it is almost certainly instrumental: the Nagel anomaloscope proves to be very sensitive to ambient temperature.
Access optionsAccess options
Subscribe to Journal
Get full journal access for 1 year
only $3.90 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Richter, M. Z. wíss. Photogr. Photophy. Photoch. 43, 209–237 (1948).
Richter, M. Klin. Mon. Augenheilkunde 119, 561–575 (1951).
Rayleigh, L. Nature 25, 64–66 (1881).
Nagel, W. A. Z. Augenheilkunde 18, 201–222 (1907).
Nagel, W. in Handbuch der Physiologischen Methodik (ed. Tigerstedt, R.) (Hirzel, Leipzig. 1909).
Waaler, G. H. M. Nature 215, 406 (1967).
Waaler, G. H. M. Avhandl. Det Norske Videnskaps-Akad. Oslo I Mat.-Naturv. Klasse. Ny Serie, No. 9, 1–25 (1967).
Pokorny, J., Smith, V. C., Verriest, G. & Pinckers, A. J. L. G. Congenital and Acquired Color Vision Defects (Grune & Stratton, New York, 1979).
De Vries, H. Experientia 4, 357 (1948).
Knowles, A. Vision Res. 20, 475–485 (1980).
Moreland, J. D. in Colour Vision Deficiencies II (ed. Verriest, G.) 14–18 (Karger, Basel, 1974).
Merton, T. R. Proc. R. Soc. 113, 704–708 (1927).
Winderickx, J. et al. Nature Genet. 1, 251–255 (1992).
Köllner, H. Arch. Augenheilkunde 78, 302–335 (1915).
Jordan, G. Polymorphism of Normal Colour Vision in Humans (University of Cambridge, Cambridge, 1992).
Heinsius, E. Farbsinnstörungen und ihre Prüfung in der Praxis (Ferdinand Enke, Stuttgart, 1973).
About this article
General and Comparative Endocrinology (2018)
Individual differences in visual science: What can be learned and what is good experimental practice?
Vision Research (2017)
PLOS ONE (2017)
Nature Communications (2017)
Journal of the Optical Society of America A (2016)