GB/T 3978-2008 in English

《GB/T 3978-2008标准照明体和几何条件》由TC120（全国颜色标准化技术委员会）归口，主管部门为国家标准化管理委员会。
本标准规定了色度学中的CIE标准照明体、代表照明体的人工光源和颜色测量仪器的几何条件。
本标准适用于颜色测量、计算和评价中照明体和几何条件的应用和表示。

Standard illuminants and geometric conditions

1 Scope

This standard specifies the geometric conditions of CIE standard illuminant, artificial light source representing illuminant and color measuring instrument in colorimetry.

This standard is applicable to the application and representation of illuminants and geometric conditions in color measurement, calculation and evaluation.

2 Normative references

The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. For undated references, the latest edition of the normative document applies.

GB/T 5698 Glossary of color terms

3 Terms and definitions

For the purposes of this standard, the terms and definitions given in GB/T 5698 as well as the following apply.

3.1
illuminant
radiation with a defined relative spectral power distribution in the wavelength range that affects the color perception of an object

3.2
CIE standard illuminants
illuminant A and illuminant D65 defined by CIE in terms of relative spectral power distribution

3.3
CIE sources
artificial light source specified by CIE, with a relative spectral power distribution similar to that of a CIE standard illuminant

 
3.4
geometric conditions
geometric relationship between light source and detector of a color measuring instrument and color sample of an object, which is different from illuminating-viewing conditions in visual evaluation

3.5
reference plane
plane on which the measured sample or reference standard is placed during measurement

3.6
sampling aperture
illuminated area on the reference plane or the area where the flux is detected by the receiver, whichever is smaller. If the illuminated area is larger than the detection area, it is called "overfilling"; if the illuminated area is smaller than the detection area, it is called "underfilling"

Foreword I
1 Scope
2 Normative references
3 Terms and definitions
4 CIE standard illuminants
5 CIE sources
6 Geometric conditions for color measuring instruments