GB/T 22505-2008Inspection of grain and oils - Sensory analysis environment-lighting (English PDF)

2.1 North Sky Light

North sky light refers to the skylight seen from the north window that avoids direct sunlight from 3 h after sunrise to 3 h before sunset.

2.2 Color Temperature

When the chromaticity of the light source is the same as that of a perfect radiator at a certain temperature, the absolute temperature of the perfect radiator is the color temperature of the light source. The symbol of color temperature is Tc and the unit is K.

2.3 General Color Rendering Index

General color rendering index refers to the average value of the special color rendering index of the light source to the 8 colors specified by CIE, and the symbol is Ra.

2.4 CIE Standard Illuminants

CIT standard illuminants refer to a specific relative spectral power distribution incident on an object as specified by CIE.

2.4.1 Standard illuminants A Standard illuminants A refer to a perfect radiator with an absolute temperature of 2,856 K in accordance with the international practical thermometric scale.

2.4.2 Standard illuminants C

Standard illuminants C refer to the average daylight with a correlated color temperature of about 6,774 K.

2.4.3 Standard illuminants D65

Standard illuminants D65 refer to the average daylight with a correlated color temperature of about 6,504 K.

2.4.4 Standard illuminants D55

Standard illuminants D55 refer to the daylight with a correlated color temperature of about 5,503 K.

2.4.5 Standard illuminants D75

Standard illuminants D75 refer to the daylight with a correlated color temperature of about 7,504 K.

2.5 Illuminance

Illuminance is the luminous flux incident on a surface element at a point on the surface divided by the area of the surface element, and the unit is (lx), 1 lx = 1 lm/m2.

3.1 Characteristics of Standard Lighting

It shall be equivalent to the color temperature and spectral distribution of north sky light. See Appendix A for the specific requirements.

3.2 Requirements for Light Source

3.2.3 The spectral distribution shall be as close as possible to the CIE standard illuminants D65 (Appendix A).

3.2.2 General color rendering index: higher than 75

3.2.1 Correlated color temperature: 6,500 K ± 200 K