GB/T 4739-1995 Method for determination of chromaticity of daily-use ceramic pigments
Some standard content:
National Standard of the People's Republic of China
Methods for measuring the colorimetry of ceramic pigments for daily use
Methods for measuring the colorimetry of ceramic pigments GB/T 4739-—1995
Replaces GB 4739--84
This standard adopts the 1964 supplementary standard colorimetry system of the International Commission on Illumination (CIE) under the conditions of Ds standard illuminant and the CIE1976L\α\6* (CIELAB) homogeneous color space system to express the color of daily use ceramic pigments (hereinafter referred to as ceramic pigments) and calculate the color difference.
Subject content and scope of application
This standard specifies the measurement conditions and methods for the colorimetry of daily use ceramic pigments. This standard applies to general daily use ceramic pigments, but not to ceramic pigments containing fluorescent substances and with metallic luster. 2 Reference standards
GB3977
Methods of expressing colors
GB3978
Standard lighting objects and lighting observation conditions
GB 3979
Methods of measuring object colors
Uniform color space and color difference formula
GB 7921
3 Principle
3.1 This standard uses an instrument to measure the spectral reflectance of ceramic pigment samples under the conditions of the Ds standard illuminant 10° field of view X1Y1.Z1 colorimetric system specified in GB3977, GB3979, and GB7921, and then obtains the three stimulus values and lightness index L" and chromaticity index a*, b* values of the samples.
3.2 Under the conditions specified in this standard, the three stimulus values X1., Y10, and Z1. of the ceramic pigment samples are calculated using the equal wavelength interval method. The calculation formulas are as follows (1), (2), and (3):
X10 = K1ZP(A)S(A)Z10(A)AA
Y1o = Ki EP(A)S(A)ye()Ad
Zo = Kio
Ke=100/
CP(A)S(A)210()A)
Xio.YioZ———Tristimulus value of the sample())—Normalization coefficient;
S()——Relative spectral power distribution of Des standard illuminant; P(>)———Spectral reflectance of the sample: (a), o(),. (a)-—Color matching function wavelength interval of XYz colorimetric system.
（3）
Weighting coefficient S(a)<）、S(a)1o(a）、S()z(a) value, select the corresponding data according to the wavelength interval. Generally, chromaticity calculation adopts 10nm wavelength interval, and the weighting coefficient value is shown in Table 1. When high-precision measurement is required, 5nm wavelength interval is used, and the weighting coefficient value is shown in Table 2. Approved by the State Bureau of Technical Supervision on July 6, 1995 and implemented on April 1, 1996
GB/T 4739—1995
3.3 The chromaticity value of ceramic pigments is measured after the sample is baked on a white porcelain plate. In order to avoid the influence of the color thickness, the spectral reflectance of the white porcelain plate used and the baking temperature on the chromaticity, the sample must be applied to the specified white porcelain plate with the same thickness and baked according to the specified baking method.
Table 1 Weighting coefficient (wavelength interval A10nm) Wavelength
s(a)(a)
s(a)yata)
S(a)zo(a)
GB/T4739—1995
Continued Table 1
S()ri()
S(aylo(a)
Table 2 Weighting coefficient (wavelength interval = 5nm)
S()1(a)
s(a)yo(a)
S(a)zn(a)
S(a)z6(a)
GB/T4739--1995
Continued Table 2
Stae(a)
US, 4394
1:8557
4:0553
No.:3217
Element:1496
S(3)210(2)
1,193
0,0000
4White porcelain plate used for preparing sample
GB/T 4739---1995
Continued Table 2
S(a)ro(a)
s(a)yi(a)
S()z(a:
4.1 White ceramic plates used for the colorimetric measurement of ceramic pigments shall be glazed on at least one side, and the glazed surface shall be used for preparing the measured surface. The entire sample shall be flat, without deflection, obvious unevenness, and the glaze surface shall be uniform and smooth without color spots. 4.2 The size of the white ceramic plate shall be determined by the instrument, and the thickness shall not be less than 5mm. 4.3 The glazed surface of the white ceramic plate shall meet the following optical performance requirements: a. Have good optical stability;
GB/T4739-1995
b. Have sufficiently good diffuse reflectivity, and have a high spectral reflectance and low spectral selectivity in the wavelength range of visible light. 4.4 The glazed surface of the white porcelain plate must be measured for color before coloring. The standard color should be X10=80±2, Y10-84±2, Zc=89±2. The color difference between the color of all white porcelain plates used in the color measurement shall not exceed 0.7 color difference units. 5 Preparation of samples
5.1 The particle fineness of the ceramic pigment used to prepare the sample should meet the requirement that the particles with a diameter of less than 15um should not be less than 90%, and the largest particle should not exceed 30 μm.
5.2 According to the method for preparing silk screen porcelain decals, mix and modulate the oil and material in a ratio of 0.5:1, use a 280 mesh (sieve size 0.055mm) polyester screen, and carefully print several sheets of decals with a thickness of about 35um according to the size of the white porcelain plate, and dry them for use. 5.3 Select several pieces of decals with uniform color and thickness, cut them, and stick them on the qualified porcelain plates according to the method of film decals. 5.4 Carry out color baking at the specified color baking temperature, and select after color baking. The sample should be bright in color, bright in color, without bubbles inside, and smooth on the surface without sticky dirt, scratches, bursts and other defects. Select a group of samples for each sample for parallel measurement, and take three pieces from each group. 5.5 The sample is generally not pretreated. In special cases, it is pretreated according to the product technical standards or the conditions agreed upon by the supply and demand parties before testing.
6 Test conditions
The room temperature when printing decals is 20±2℃, and the relative humidity is (50±25)%. 7 Experimental instruments and lighting observation conditions
7.1 Use a spectrophotometer and a photoelectric integral colorimeter. The technical conditions of the instrument should comply with the provisions of GB3979. 7.2 The instrument uses the Ds standard lighting body specified in GB3978. 7.3 The lighting observation conditions of the instrument adopt the two geometric optical conditions of o/d and d/a specified in GB3979. 8 Standard white plate and working white (color) plate
8.1 The standard white plate should be a diffuse white plate pressed by powders such as barium sulfate and magnesium oxide. Its thickness should be greater than 5mm and its diameter should be more than 25mm. The surface of the standard white plate should be flat, without texture, glossiness, or stains. 8.2 The standard working white (color) plate of the instrument adopts a ceramic white (color) plate. The surface should be flat, clean, uniform in color, free of bubbles, spots and other defects, with good directional uniformity and high spectral reflectance. If necessary, it can be calibrated with a standard white plate. 8.3 The standard white plate and working standard color plate must be calibrated regularly by the national metrology department. 9 Measurement steps
9.1 Spectral colorimeter
Preheat and calibrate the instrument according to the requirements of the instrument manual, and adjust the slit width according to the selected wavelength interval to achieve a reasonable balance between spectral resolution and sensitivity. Generally, monochromatic light with a half-width of 5nm or 10nm is used, with a wavelength interval of △^=10nm, and the measurement is carried out in the full range of the spectrum 380780nm. However, if a highly saturated color with a steep and narrow spectral reflectance curve is encountered, monochromatic light with a half-width of 2.5nm can be used, and the wavelength interval ^A=5nm can be used for measurement. According to the selected measurement conditions, the spectral reflectance of the sample relative to the standard self-plate is measured, and the spectral tristimulus values X10, Y10, Z. and chromaticity coordinates 210~Y1 values of the sample are calculated by the instrument data system. 9.2 Photoelectric integral colorimetric instrument
Preheat and calibrate the instrument according to the requirements of the instrument manual, and then place the test sample on it to directly measure the tristimulus values X10, Yu, Zt and chromaticity coordinates and other color parameters of the sample. 10 Calculation and representation of results
10.1 The tristimulus values of each sample are read directly by the instrument. The tristimulus values of each group of samples are expressed as the arithmetic mean of the tristimulus values of the group of samples, accurate to one decimal place. GB/T 4739-
—1995
10.2 The chromaticity coordinates of the sample are calculated using formulas (4), (5) and (6). The calculation results are rounded to four decimal places. To = Xio/(Xio+ Yi + Zio)
Yr Y10/(X +Y1o +Zo)
21o = Z1/(X1o +Y1o + Z10)
Where: 020--- Chromaticity coordinates of the sample. 10.3 The L* and Q*6* of the sample are calculated according to formulas (7), (8), (9) and (10). The calculation results are rounded to two decimal places and expressed as lightness index L\ and chromaticity index α” and b. L+ -116(Y/Y,)1/3 -- 16
(Yn/Y, > 0.008856)
L* =903. 3(Yn/Y.)
(Y10/Y, ≤ 0. 008856)
a* =500[f(X./X.) - f(Yio/Y.)]6* =200[f(Y1/Y,) --f(Z10/Z.)] Where: f(Xto/X,)=(X/X,)1/a
(X/X.>0. 008856)
f(X/X.)=7.787(X10/X.)+16/116f(Y1./Y,)--(Y10/Y.)1/3
(X./X.≤0.008856)
(Y1/Y.>0. 008856)
f(Y10/Y.)=7.787(Y10/Y.)+16/116f(Z10/Z.)=(Z10/Z.)13
(Y1./Y,≤0. 008856)
(Z10/Z,>0. 008856)
f(Zo/Z.)=7. 787(Zu/Z.)+16/116X..Y.、Z.-
(Z1/Z,≤0.008856)
The tristimulus values of the completely reflecting diffuser are shown in Table 3. Table 3 Tristimulus values and chromaticity coordinates of the completely reflecting diffuser Tristimulus values and chromaticity coordinates
=10 nm
10.4 Calculate the hue angle of the sample according to formula (11) and refer to the following figure for representation: The calculation result is rounded to one decimal place. hab = arctg(b\ /a\)
In the formula: hb—
hue angle, ()
When α>0.6°>0, h is between 0° and 90°, which is from red to yellow; when α<0, 6*≥0, h is between 90° and 180°, which is from yellow to green. When a<06<0, h is between 180° and 270°, which is from green to blue. When α>0, 6\<0, h is between 270° and 360°, which is from blue to red. =5nm
·（5）
.（8）
（9）
.（ 10 )
10.5Calculate the chromaticity value of the sample according to formula (12). The calculation result is rounded to one decimal place.
Wherein: Cb
-chromaticity.
10.6Calculate the color difference value of the sample according to formula (13): The calculation result is rounded to one decimal place. Yellow-green
GB/T 4739
9—1995wwW.bzxz.Net
Chromaticity index diagram
Ch =(a*2 +b*2)1/2
AE% = [(AL*)2 + (Aa')2 + (AS*)271/2Wherein: △E%---color difference between two tested samples; AL\--difference in brightness index of two tested samples; Aa*Ab*-
-difference in chromaticity index of two tested samples.
10.7 If necessary, the color difference, chroma difference and hue difference of the sample can be calculated according to formulas (14), (15), (16) and (17): the calculation results are rounded to one decimal place. AE [(AL*+(ACh)a +(AH)2
ACh = Ch - Chb.
AH% =[(AE)—(AL)(AC)\12
Ahab = hab - habe
The sign of AH is the same as the sign of Ah.
Where: hb is the chromaticity value of the reference sample; AC% is the chromaticity difference between the sample under test and the reference sample: AH is the hue difference between the sample under test and the reference sample. 11 Test report
The test report shall at least include the following contents: indicate reference to or compliance with this national standard; a.
（12）
（14 ）
（15）
?( 16)
·( 17)
GB/T 4739—1995
Name, type, baking temperature of ceramic pigments and standard samples: varieties and color difference range of white porcelain plates; methods and conditions for preparing samples;
model of instrument, standard illuminant, lighting observation conditions, wavelength interval; clearly indicate the non-compliance with this standard or other methods adopted; report the measurement results as needed;
measurement date, measurement personnel.
Additional remarks:
This standard was proposed by China Light Industry General Association.
This standard is under the jurisdiction of the National Ceramic Standardization Center. This standard was drafted by Shandong Silicate Research and Design Institute. The main drafters of this standard are Yin Xiangdong, Li Lun, Dong Guiying, Tang Yuanqin, and Wang Jizhen. 71When h is between 0° and 90°, it is a red to yellow tone; when α<0, 6*≥0, h is between 90° and 180°, it is a yellow to green tone; when a<06<0, h is between 180° and 270°, it is a green to blue tone. When α>0, 6\<0, h is between 270° and 360°, it is a blue to red tone. =5nm
·（5）
.（8)
（9）
.（ 10 )
10.5Calculate the chroma value of the sample according to formula (12). The calculation result is rounded to one decimal place.
Where: Cb
-chroma.
10.6Calculate the color difference value of the sample according to formula (13): The calculation result is rounded to one decimal place. Yellow-green
GB/T 4739
9—1995
Chromaticity index diagram
Ch =(a*2 +b*2)1/2
AE% = [(AL*)2 + (Aa')2 + (AS*)271/2Where: △E%—--color difference between two tested samples; AL\—difference in lightness index between two tested samples; Aa*Ab*-
-difference in chromaticity index between two tested samples.
10.7If necessary, the color difference, chroma difference and hue difference of the sample can be calculated according to formulas (14), (15), (16) and (17): the calculation result is rounded to one decimal place. AE [(AL*+(ACh)a +(AH)2
ACh = Ch - Chb.
AH% =[(AE)—(AL)(AC)\12
Ahab = hab - habe
The sign of AH is the same as the sign of Ah.
Where: hb is the chromaticity value of the reference sample; AC% is the chromaticity difference between the sample under test and the reference sample: AH is the hue difference between the sample under test and the reference sample. 11 Test report
The test report shall at least include the following contents: indicate reference to or compliance with this national standard; a.
（12）
（14 ）
（15）
?( 16)
·( 17)
GB/T 4739—1995
Name, type, baking temperature of ceramic pigments and standard samples: varieties and color difference range of white porcelain plates; methods and conditions for preparing samples;
model of instrument, standard illuminant, lighting observation conditions, wavelength interval; clearly indicate the non-compliance with this standard or other methods adopted; report the measurement results as needed;
measurement date, measurement personnel.
Additional remarks:
This standard was proposed by China Light Industry General Association.
This standard is under the jurisdiction of the National Ceramic Standardization Center. This standard was drafted by Shandong Silicate Research and Design Institute. The main drafters of this standard are Yin Xiangdong, Li Lun, Dong Guiying, Tang Yuanqin, and Wang Jizhen. 71When h is between 0° and 90°, it is a red to yellow tone; when α<0, 6*≥0, h is between 90° and 180°, it is a yellow to green tone; when a<06<0, h is between 180° and 270°, it is a green to blue tone. When α>0, 6\<0, h is between 270° and 360°, it is a blue to red tone. =5nm
·（5）
.（8)
（9）
.（ 10 )
10.5Calculate the chroma value of the sample according to formula (12). The calculation result is rounded to one decimal place.
Where: Cb
-chroma.
10.6Calculate the color difference value of the sample according to formula (13): The calculation result is rounded to one decimal place. Yellow-green
GB/T 4739
9—1995
Chromaticity index diagram
Ch =(a*2 +b*2)1/2
AE% = [(AL*)2 + (Aa')2 + (AS*)271/2Where: △E%—--color difference between two tested samples; AL\—difference in lightness index between two tested samples; Aa*Ab*-
-difference in chromaticity index between two tested samples.
10.7If necessary, the color difference, chroma difference and hue difference of the sample can be calculated according to formulas (14), (15), (16) and (17): the calculation result is rounded to one decimal place. AE [(AL*+(ACh)a +(AH)2
ACh = Ch - Chb.
AH% =[(AE)—(AL)(AC)\12
Ahab = hab - habe
The sign of AH is the same as the sign of Ah.
Where: hb is the chromaticity value of the reference sample; AC% is the chromaticity difference between the sample under test and the reference sample: AH is the hue difference between the sample under test and the reference sample. 11 Test report
The test report shall at least include the following contents: indicate reference to or compliance with this national standard; a.
（12）
（14 ）
（15）
?( 16)
·( 17)
GB/T 4739—1995
Name, type, baking temperature of ceramic pigments and standard samples: varieties and color difference range of white porcelain plates; methods and conditions for preparing samples;
model of instrument, standard illuminant, lighting observation conditions, wavelength interval; clearly indicate the non-compliance with this standard or other methods adopted; report the measurement results as needed;
measurement date, measurement personnel.
Additional remarks:
This standard was proposed by China Light Industry General Association.
This standard is under the jurisdiction of the National Ceramic Standardization Center. This standard was drafted by Shandong Silicate Research and Design Institute. The main drafters of this standard are Yin Xiangdong, Li Lun, Dong Guiying, Tang Yuanqin, and Wang Jizhen. 71
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