The possibility of realizing daylight simulators satisfying the conditions specified in JIS Z 8720-1983 and Publication CIE No.51, with line spectrum illuminants composed of several monochromatic radiations (lines), was examined by a nonlinear programming technique.
It was found possible to realize sinulators satisfying:
(1) the condition of a visible range metamerism index
MIuv ≤ 0.5 (CIELAB
10) with 5 spectral lines,
(2) the condition of an ultraviolet range metamerism index
MIuv ≤ 1 (CIELAB
10) with 3 lines,
(3) both
MIuv ≤ 0.5 and
MIuv ≤ 1, while the general color rendering index
Ra is not sufficietly high, with 6 lines,
(4)
Ra ≤s 95 (CIE 2nd Edition), while
MIuv is not sufficietly good, with 5 lines, and
(5)
MIuv ≤ 0.5,
MIuv ≤ 1 and
Ra ≥ 95 with 7 lines.
(6) Six lines are necessary to realize both
MIuv ≤ 0.5 and
Ra ≥ 95, in contrast with 5 lines in cases (1) and (4).
These results show that the general color rendering index is a different measure from the metamerism index, and useful to supplement the latter for the assessment of daylight simulators. However, it is suggested that daylight simulators in eithr case (5) or (6) are insufficient to reproduce the color appearance of chromatic fluorescent objects excited by visible range radiation under a natural daylight illuminant.
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