Abstract

A colorimeter was used in which the adjustable primaries can be extinguished separately, and in which the comparison stimulus is synthesized by an equivalent optical system, thus assuring a physical as well as a visual match. After a few matches were obtained in the customary manner, two of the adjustable primaries were left undisturbed and the third was merely flashed intermittently, five seconds off, one-half second on. After observation of one or two cycles, a great difference is apparent between the two halves of the field during the half-second when all three primaries are on. When the red primary is intermittent, the lower semicircle appears bluish-green for five seconds, and much too reddish to match the upper half during the brief flash. The observers then readjusted the primaries until the two halves of the field appeared to match during the flash. Each primary was made intermittent, in turn, and also each pair of primaries, giving measurements of the effect for six different directions around each comparison color. Achromatic and moderately saturated red, green, and purple comparison colors were investigated. The intermittent stimulus which appears to match the steady stimulus lies very nearly on the straight line in the chromaticity diagram connecting the latter with the adapting stimulus.

© 1949 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. W. R. J. Brown and D. L. MacAdam, J. Opt. Soc. Am. 38, 1093 (1948).
  2. H. Helson and W. S. Michels, J. Opt. Soc. Am. 38, 1025–1033 (1948).
    [Crossref] [PubMed]
  3. R. M. Evans, J. Opt. Soc. Am. 33, 579–614 (see pp. 600, 601) (1943).
    [Crossref]

1948 (2)

W. R. J. Brown and D. L. MacAdam, J. Opt. Soc. Am. 38, 1093 (1948).

H. Helson and W. S. Michels, J. Opt. Soc. Am. 38, 1025–1033 (1948).
[Crossref] [PubMed]

1943 (1)

Brown, W. R. J.

W. R. J. Brown and D. L. MacAdam, J. Opt. Soc. Am. 38, 1093 (1948).

Evans, R. M.

Helson, H.

MacAdam, D. L.

W. R. J. Brown and D. L. MacAdam, J. Opt. Soc. Am. 38, 1093 (1948).

Michels, W. S.

Cited By

OSA participates in Crossref's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (8)

F. 1
F. 1

Elevation, showing arrangement of adjustment section of additive colorimeter. Diagonal, semitransparent mirrors reflect and transmit beams from lamps into photometric cube, C. Primary filters are shown to left of mirrors.

F. 2
F. 2

End view, showing relative placement of adjustment and comparison systems of colorimeter.

F. 3
F. 3

Plan showing arrangement of lamp, L4, mirrors, and filters in comparison stimulus system. Beam passing directly through provides red primary. Beam reflected from left passes through green filter. Top of one movable lamp, L3, and the photometric cube, C, and eyepiece, E, are shown.

F. 4
F. 4

Effect of adaptations on momentary matches for nearly neutral stimulus, C. A1 to A6 represent six different adaptations. Solid dots indicate adaptations for WRJB, open circles for DLM, crosses for HRC. M1 indicates chromaticities necessary to match C after adaptation to A1, with same code for the three observers. Straight lines from C toward adaptation chromaticities pass near chromaticities required for match.

F. 5
F. 5

Effects of adaptations on momentary matches for purple stimulus. Same code as in Fig. 4.

F. 6
F. 6

Effects of adaptations on momentary matches for green stimulus, C. Same code as in Figs. 4 and 5 for observers WRJB and DLM only.

F. 7
F. 7

Effects of adaptation on momentary matches for red stimulus, C. Same code as in Figs. 4, 5, and 6. Two results shown for each observer and condition, indicating repeatability.

F. 8
F. 8

Correlation between effects of adaptations and magnitudes of adapting stimuli. Abscissas are ratio of ICI tristimulus sums: that of the matching stimulus divided by that of the adapting stimulus. Ordinates are distances in ICI diagram between matched stimuli expressed as fractions of distance from self-adapting comparison stimulus to adapting stimulus of matching field.

Tables (4)

Tables Icon

Table I Colorimetric specifications of local adaptation and matching stimuli.

Tables Icon

Table II Colorimetric specifications of local adaptation and matching stimuli.

Tables Icon

Table III Colorimetric specifications of local adaptation and matching stimuli.

Tables Icon

Table IV Colorimetric specifications of local adaptation and matching stimuli.

Equations (5)

Equations on this page are rendered with MathJax. Learn more.

x = X / ( X + Y + Z ) , y = Y / ( X + Y + Z ) ,
X = 0.577 B + 1.026 G + 14.37 R . Y = 0.345 B + 1.967 G + 6.27 R . Z = 2.887 B + 0.080 G + 0.20 R .
r = 1 / ( 1 + 0.21 R 2 ) ,
r = 1 / ( 1 + 0.54 R 2 ) .
r = 1 / ( 1 + 0.54 R 3 ) .