GB/T 20146-2006
CIE standard illuminants for colorimetry (English Version)

GB/T 20146-2006
Standard No.
GB/T 20146-2006
Language
Chinese, Available in English version
Release Date
2006
Published By
General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China
Latest
GB/T 20146-2006
Scope
This standard specifies two types of illuminants used in colorimetry. The illuminants defined in Chapters 4 and 5 are as follows: a) CIE Standard Illuminant A This illuminant is used to represent For tungsten lighting, the relative spectral energy distribution is the relative spectral energy distribution of the Planck radiator at a temperature of about 2856K. CIE Standard Illuminant A applies to all aspects of colorimetry involving the use of incandescent lighting, except when there are special reasons for using a different illuminant. b) CIE standard illuminant D65 This illuminant is used to represent average daylight and has a correlated color temperature of about 6500K. CIE standard illuminant D65 should be used in all colorimetric calculations requiring typical daylight unless there is a special reason to use a different illuminant. It is known that the relative spectral energy distribution of daylight varies with season, time of day and geographical location, especially in the ultraviolet spectral region. Nevertheless, until supplementary information on these variables is available, CIE Standard Illuminant D65 should be used. The relative spectral power distribution values of CIE standard illuminants A and D65 are given in Table 1 of this standard. The values are given at intervals of 1 nm between 300 nm and 830 nm. The term "illuminant" refers to a defined spectral power distribution, not necessarily achievable or provided by a light source. In colorimetry, illuminants are used to calculate the tristimulus values of reflected or transmitted object colors under specified lighting conditions. CIE also defines illuminant C and other illuminant D. These illuminants are discussed in CIE15.2:1986. However, they do not have the same main CIE standard status as CIE standard illuminants A and D65 described in this standard, it is recommended to use one of these two CIE standard illuminants specified in this standard as much as possible, which will greatly promote the Comparability of results. The CIE illuminant D50 is also widely used in the graphic arts and photography, as described for example in ISO 3644 and ISO 13655. In most practical applications of colorimetry, it is sufficient to use the values of CIE standard illuminant A and D65 in the spectral region that is larger than the wavelength interval specified in this standard or the spectral range is narrower than that specified in this standard. CIE 15.2 provides data and guidance to aid in this practice and other recommended procedures for practical colorimetric measurements. The term "light source" refers to a physical emitter of light, such as a lamp or the sky. In some cases, CIE recommends the use of laboratory light sources that approximate the spectral power distribution of the CIE illuminant. In all cases, however, defining a CIE-recommended illuminant is secondary to defining the CIE illuminant to which that illuminant corresponds, as new research often leads to advances in illuminants that can more precisely Represents a specific illuminant or is more suitable for use in the laboratory. 6.1 of this standard describes the CIE illuminant A recommended for the realization of the CIE standard illuminant A in the laboratory. Currently, CIE has not yet recommended a light source to represent the CIE standard illuminant D65.

GB/T 20146-2006 Referenced Document

GB/T 20146-2006 history



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