Table 1.

Information capacity C, in bits, preserved in natural scenes under various changes in daylight^a

		Codes with LMS spectra		Codes with sharpened spectra
Illuminant change		von Kries	Spatial ratio	von Kries	Spatial ratio
25,000 K – 6500 K	Mean C	11.43	11.02	14.44	14.08
	S.D. C	0.76	0.69	1.36	1.28
4000 K – 6500 K	Mean C	11.78	11.37	13.90	13.40
	S.D. C	0.72	0.69	1.71*	1.84*
25,000 K – 4000 K	Mean C	8.62	8.19	11.34	10.83
	S.D. C	0.73	0.67	1.42	1.55

^aEntries show means and sample standard deviations of C for von-Kries scaling of cone responses, the spatial ratio of unscaled cone responses, and those codes with optimally sharpened cone spectral sensitivities. Correlated color temperature of the illuminant changed from 25,000 K to 6500 K, 4000 K to 6500 K, and 25,000 K to 4000K. Data based on a sample of 25 rural and urban scenes each of size 1344 × 1024 pixels.

^*S.D. ≤ 1.53 if one scene omitted (see text).