Some standard content:
National Standard of the People's Republic of China
Method of evaluating color rendering properties of light sources
UDC 628.938
GB5702—85
This standard quantitatively evaluates the color rendering properties of light sources based on the total chromaticity shift of the test color sample under the illumination of the reference light source and the light source to be tested. This standard is applicable to the evaluation of color rendering properties of artificial lighting sources, such as incandescent lamps, halogen tungsten lamps, various gas discharge lamps (fluorescent lamps, high-pressure sodium lamps, metal halide lamps, recessed lamps, etc.), artificial long lights, etc., except for light sources with dominant monochromatic radiation such as low-pressure sodium lamps. 1 Evaluation method
1.1 Selection of reference light source
When evaluating the color rendering properties of light sources, select a reference light source, and the spectral power distribution of the reference light source is defined by a mathematical formula. When the correlated color temperature of the light source to be measured is lower than 500K, the Planck radiator is used as the reference light source, and the spectral power distribution is calculated using the Planck formula.
S(a)-Cx-t(e x1)
Wherein: S ()
Light source spectral power distribution:
C…Planck's first radiation constant, w·m
C. 3.7415 × 10
C,——Planck's second radiation constant, m-KIC, - 1. 1388 × 111**
·wavelength.m
T —-color temperature. K.
When the correlated color temperature of the measured light source is higher than 5000K, the combined whole light is used as the reference light source. When the correlated color temperature is known, its light evaluation power distribution S () is calculated according to Formula 2).
S(A) =S.(a)mS(a)-m,S,(A)
: S.(), S.(a), S.ca)-
Coefficients used to calculate the daylight spectrum distribution, whose values are given in Table 1: Quantities related to the color coordinates of the light source.
- 1. 3515 - 1, 7703 3, + 5. 7114 9 n0. 0241 - 0. 2562 ±, -0. 7341 y,0.0300-31.4424x-30.071791
m,=-o.0241 +0.2562±n-0.7341 yn In the formula: .W
refers to the CIE1931 chromaticity coordinates of the light source. Un =- 3. 000 x: -2. 874xp - 0. 2750 Issued by National Bureau of Standards on December 5, 1985
（2）
Implemented on September 1, 1986
x, = - 4- 6070 .bzxz.net
GB 6702-86
(4000K , T.7000 K )
-2-0064
(7000KT-2500K)
0.244 063
+0.237040
The color temperature of the reference light source should be the same or close to that of the light source to be measured. After the chromaticity of the light source to be measured is obtained, the color temperature of the illumination light source is determined by the chromaticity diagram or calculation method. The spectral power distribution of the reference light source is calculated by formula (1) or (2): 1.2 Tolerance of the reference light source
When the chromaticity difference △C between the reference light source and the light source to be measured is less than 5.4×10- (equivalent to 15mireds), the AC value is calculated by formula (8):
A'c = ( (uk—ur)\+ (h,)\?
Where: ux. w
ur, ur
--u coordinate value of the light source to be tested:
, refer to the u coordinate value of the light source.
1.3 Test color samples
Select 8 color samples as a group (=1,, 8) as the test color samples for evaluating the general color rendering index, and their spectral brightness coefficients are shown in Table 2
Select 7 color samples (=9, *, 15) as the test color samples for evaluating the special color rendering index, which represent deep red, deep yellow, deep green, deep blue, native skin color, leaf green, and Chinese female skin color. The spectral brightness coefficient values are shown in Table 3.1.4 The determination of the CIE1931XYZ tristimulus values of the test color samples requires the measurement of the relative spectrum of the light source to be tested Power distribution. The spectral brightness coefficient values of the test color samples are given in Tables 2 and 3, and the CIE1931 standard chromaticity observer spectral tristimulus values (), (λ), (λ) are given in Table 4. According to GB3977-8 "Color Representation Method", the CIE1931XYZ tristimulus values and CIE19312y chromaticity coordinate values of the test color samples under the illumination of the reference light source and the light source to be tested are calculated respectively. The tristimulus value calculation adopts the equal wavelength interval method, and the wavelength interval λ is generally 5nm or 10nm. 1.5 Convert from u coordinate to coordinate
Use formula (9) or (19) to convert the chromaticity coordinate value from y coordinate to u coordinate, 4x
X+15Y+3z
X r15y+8 z
where: , - — chromaticity coordinates of the test color sample; — ~ CIE1931XYZ tristimulus values of the test color sample. X, Y, Z
where. r, y-
: 2x+12y+3
- 2r+12y+3
— CIE1931y chromaticity coordinates of the test color sample. 1.6 Correction of chromaticity shift of chromatic adaptation
GB 570285
Because the state of chromatic adaptation under the illumination conditions of the light source to be tested and the seasonal light source is different, the correction of chromaticity shift of chromatic adaptation is made using formulas (11) and (12).
10-872+0.404
16 .518 + 1. 481
16 .518 + 1. 481
Where: t+ k,
the coordinate value of the i-th test color sample under the light source to be tested after the color adaptation chromaticity shift correction, the color adaptation chromaticity shift correction value,
represents the subscript of the reference light source;
represents the subscript of the light source to be tested;
represents the subscript of the test color sample number.
(1. 708 + 0. 404 - 1. 481±)(13)
-(14 )
Table 5 gives the color adaptation chromaticity shift correction value C:d. In the table, "p" represents the Planck radiator, and "D\" represents the combined daylight. 1.7 Convert u, U, Y to U*, V*, W* Use formula (15) to convert u, U, Y to U*, V*, W*. W* = 25 yi - 17
U* = 13 W* (u- u,)
y*- 13w* tw- w.)
W*= 25 yi - 17
U*= 13 W* (u- u,)
y*- 13w* tw- w.)
W*= 25 yi - 17
U*= 13 W* (u- u,)
y*- 13w* tw- w.)
W*= 25 yi - 17
U*= 13 W* (u- u,)
y*- 13w* tw- w.)
W*= 25 yi - 17
U*= 13 W* (u- u,)
y*- 13w* tw- w.)
W*= 25 yi - 17
U*= 13 W* (u- u,)
y*- 13w* tw- w.)
W*= 25 yi - 17 1.B Calculation of color difference
Use formula (1f) to calculate the color difference (E, AEt = [ (w..- wt.)'+ (Ut.+- Uk.,)+(Vt.+ - v.))!(AW*)*- (AUi)'+ (AVT)!
The subscripts in the formula have the same meaning as before.
Color rendering index
2.1 Symbol of color rendering index
The letter R represents the color rendering index, R. represents the special color rendering index, and R. represents the general color rendering index. 2.2 Calculation of special color rendering index
Use formula (17) to calculate the special color rendering index. The calculation result is an integer:
2.3 Calculation of general color rendering index
GB 5702--:
R, - 100 - 4. 6AE
The general color rendering index is obtained by taking the arithmetic mean of 8 special color rendering indices (i=1,,8) ZR
Table 1 Coefficient value for calculating the spectral distribution of combined superimposed light 2
S (A)
GB 5102
Continued Table 1
s. ()
- 13-3
Yin Color rendering index calculation using the brightness coefficient of color samples 1 to 8-
Center 466
GB5T02--85
Continued Table 2
.0.285
.0.252
#：185
n. 401
0, 445
(h 66 3
GB 5T0285
1Spectral brightness coefficients of color samples 9 to 15 for CIE special color rendering index calculationTable 3
.1.116
1, 814
0, x:7
1, 75y
GB5702-85
Continued Table 3
.n.323
(1, 017
0, 277
GB 5702—85
Table 4 CIE193I standard chromaticity observer spectral stimulus value
0-0076
n,195-1
o,tmen
11. 40173
. H! ait
11. 87 Qc
z(A）
. 3 62
1-6456
. 27 241
Ih. 01 22
1, 203
.ac.27
e,ao1?
Sum by interval
Zra=21.3714
Z()=21.3711
()=21.3715
GB 5702-85
1). 171:
. 17 1
1, 0-146
t,ty32
a,onyy
. 3051
small.28 68
GB 5702—B5
Color adaptation color shift meal positive value heart
0-3563
n-3547
1,2481
，F69
0, 8129
0,8648
.1.5749
F3300K
3400 K
3501 K
P3550K
P4400K
5000 K
35702-85
Continued Table 5
0,3415
. 3224
1-9007
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