Standard Illuminant D50 (1964)
D50.5nm |
standard Illuminant D50, from 300 to 830 nm at 5 nm intervals. |
A colorSpec object organized as a vector, with 107 data points
and specnames equal to 'D50'.
This spectrum is not copied from a table from a CIE publication, though it does match such a table.
It is computed using the function daylightSpectra() by following
the special CIE recipe given in the References.
The temperature is set to (14388/14380) * 5000 = 5002.781 Kelvin.
The coefficients of the daylight components S_0, S_1, and S_2 are
rounded to 3 decimal places.
This linear combination is computed at 10nm intervals and then linearly interpolated to 5nm intervals.
The result is normalized to value 1 at 560nm (instead of the usual 100),
and finally rounded to 5 decimal places. See Examples.
Günther Wyszecki and W.S. Stiles. Color Science : Concepts and Methods, Quantitative Data and Formulae. Second Edition. Wiley-Interscience. 1982. Table I(3.3.4) pp. 754-758
CIE 15: Technical Report: Colorimetry, 3rd edition. CIE 15:2004. Table T.1, pp 30-32, and Note 5 on page 69.
Schanda, Janos. CIE Colorimetry, in Colorimetry: Understanding the CIE System. Wiley Interscience. 2007. p. 42.
ABC ,
D65 ,
daylightSpectra
# the CIE recipe for computing D50.5nm correction = 14388 / 14380 # note 5, page 69 in CIE 15:2004 D50.10nm = daylightSpectra( correction*5000, wavelength=seq(300,830,by=10), roundMs=TRUE ) D50.5nm = resample( D50.10nm, seq(300,830,by=5), method='linear' ) D50.5nm = round( D50.5nm, 5 ) summary( D50.5nm ) white.point = product( D50.5nm, xyz1931.1nm, wave='auto' )
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