This practice provides the values and practical computation
procedures needed to obtain CIE tristimulus values from spectral
reflectance, transmittance, or radiance data for objectcolor
Procedures and tables of standard values are given for computing
from spectral measurements the CIE tristimulus values X, Y, Z,
and chromaticity coordinates x, y for the CIE 1931 standard
observer and X10, Y10, Z10 and x10. y10 for the CIE 1964
supplementary standard observer.
Standard values are included for the spectral power of six CIE
standard illuminants and three CIE recommended fluorescent
Procedures are included for cases in which data are available
only in more limited wavelength ranges than those recommended, or
for a measurement interval wider than that recommended by the CIE.
This practice is applicable to spectral data obtained in accordance
with Practice E1164 with 1-, 5-, 10-, or 20-nm measurement
Procedures are included for cases in which the spectral data
are, and those in which they are not, corrected for bandpass
dependence. For the uncorrected cases, it is assumed that the
spectral bandpass of the instrument used to obtain the data was
approximately equal to the measurement interval and was triangular
in shape. These choices are believed to correspond to the most
widely used industrial practice.
This practice includes procedures for conversion of results to
color spaces that are part of the CIE system, such as CIELAB and
CIELUV (3). Equations for calculating color
differences in these and other systems are given in Practice
The values stated in SI units are to be regarded as standard. No
other units of measurement are included in this standard.
This standard does not purport to address all of the safety
concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and
health practices and determine the applicability of regulatory
limitations prior to use.
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