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A. R. Robertson, Proceedings of 18th Session of CIE, London, 1975 (Bureau Central, Commission Internationale de l’Eclairage, 4 Av. du Recteur Poincaré, 75–Paris 16e, France, 1976), Paper No. 10.
J. P. Guilford, Psychometric Methods, 2nd ed. (McGraw-Hill, New York, 1954), p. 125.
G. Wyszecki and W. S. Stiles, Color Science (Wiley, New York, 1967), p. 1152.
It is difficult to draw any finer comparisons between the two studies, because the same Munsell colors were not employed as stimuli. There are two exceptions, however; two color centers, 5Y 8/8 and N 6, were used in both studies. For the former, Bellamy and Newhall obtained a hue limen of 0.67, a chroma limen of 0.31, and a value limen of 0.04. We obtained a hue limen of 0.30 a chroma limen of 0.16, and a value limen of 0.05. The agreement therefore in this case is poor. For the achromatic sample, Bellamy and Newhall obtained a value limen of 0.023 and we obtained 0.024. The agreement therefore in this case is very good.
A. R. Robertson (personal communication).
See, however, Ref. 10, footnote 14, p. 1152.
These values actually correspond to the average proportional increase of the square root of the ellipse area. The square root of the ellipse area was taken so that the increase could be compared with the luminance increase (a linear change).
Only a small increase of ellipse area and ΔY/Y size was found for the N 6/ color center. This may be due to a crispening effect, because its tristimulus values were almost identical to those of the surround color. Or, perhaps the surround counteracted the effect of the dividing-strip width by appearing as an extension of the test color.