GB/T 9754-2025 Paints and varnishes - Determination of gloss value at 20°, 60° and 85° ENGLISH, PDF
1 Scope
This document specifies a method for determining the gloss of coatings using the three geometries of 20°, 60° or 85°.
The method is suitable for the gloss measurement of non-textured coatings on plane, opaque substrates.
Note: On test specimens different from these mentioned above, comparative gloss measurements are possible. However, it is not ensured that the obtained gloss values correspond to the visual gloss perception (see Annex A).
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1514 Paint and varnishes - Standard panels for testing
Note: GB/T 9271-2008, Paints and varnishes standard panels for testing (ISO 1514:2004, MOD)
ISO 2808 Paints and varnishes - Determination of film thickness
Note: GB/T 13452.2-2008, Paints and varnishes - Determination of film thickness (ISO 2808:2007, IDT)
ISO 4618 Paints and varnishes - Terms and definitions
Note: GB/T 5206-2015, Paints and varnishes - Terms and definition (ISO 4618:2014, IDT)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4618 and the following apply.
3.1
gloss
optical property of a surface, characterized by its ability to reflect light specularly
Note: Examples of degrees of gloss are high gloss, gloss, silk gloss, semigloss, satin, matt, and dead matt.
[SOURCE: ISO 4618:2014, 2.132]
3.2
geometry
identification of a method of gloss measurement using a specified angle with assigned apertures
3.3
gloss value
ratio multiplied by 100 of the luminous flux reflected from a specimen to that reflected by a glass surface with a refractive index of 1.567 at a wavelength of 587.6 nm in specular direction for a specified reflection angle and specified aperture angles of light source and receptor
Note 1: The gloss value is indicated in gloss units (GU). It is not permitted to interpret and express gloss values as "% reflection".
Note 2: Gloss values measured on coatings are expressed rounded to the nearest integer (without decimals).
Note 3: To define the gloss scale, polished black glass with a refractive index of 1.567 at a wavelength of 587.6 nm is assigned to the value of 100 for 20°, 60° and 85° geometries.
Note 4: A glass surface with a reflective index of 1.567 at a wavelength of 546.1 nm (which is the central wavelength of the spectral luminous efficiency function) may be used.
Note 5: The gloss value is influenced by the surface characteristics, e.g. roughness, texture, structure, of the sample.
4 Principle
With a reflectometric apparatus, gloss values are determined on coated surfaces, correlating with the visual gloss perception. In this context (glossmeter), the ratio of the gloss of the coating and the gloss of a polished plane glass plate with specified reference refractive index is obtained.
The method of gloss measurement is specified by the following parameters:
——measuring angles;
——field stop apertures;
——spectral adaptation;
——reference refractive index.
5 Basic principles of the gloss measurement
Gloss is a visual perception caused by looking at surfaces. The specular reflection of objects is even more distinct when light is reflected more directionally from the surface. The incident light is reflected on high-gloss surfaces only in the main specular direction. On matt surfaces the light is not only reflected in the main specular direction but also diffusely scattered in all solid angles. The more uniformly the light is scattered into the space the smaller is the intensity of the directed component and the matter the surface appears.
Contents Foreword I 1 Scope 2 Normative references 3 Terms and definitions 4 Principle 5 Basic principles of the gloss measurement 6 Apparatus and calibration equipment 6.1 Glossmeter 6.2 Measurement standards (certified reference material, working measurement standards) 1) 7 Test panels 7.1 Substrate 7.2 Preparation and coating 7.3 Drying and conditioning 7.4 Thickness of coating 8 Calibration and adjustment of the glossmeter 8.1 Preparation of the apparatus 8.2 Zero point check 8.3 Calibration and adjustment 9 Procedure 9.1 Selection of geometry 9.2 Gloss measurement 10 Precision 10.1 General 10.2 Repeatability limit 10.3 Reproducibility limit 11 Test report Annex A (normative) Possible sources of error A.1 General A.2 Topographical effects A.3 Geometrical effects A.4 Optical effects A.5 Physical effects Annex B (normative) Calibration standards B.1 Classification and use of the calibration standards B.2 Production of calibration standards B.3 Handling of the calibration standards Annex C (informative) Gloss calculation of primary reference standards C.1 Physical basis C.2 Gloss calculation Annex D (informative) Details on precision D.1 General remark on the interlaboratory test D.2 Samples D.3 Glossmeters D.4 Number of measurements D.5 Expression of results Bibliography
GB/T 9754-2025 Paints and varnishes - Determination of gloss value at 20°, 60° and 85° ENGLISH, PDF
1 Scope
This document specifies a method for determining the gloss of coatings using the three geometries of 20°, 60° or 85°.
The method is suitable for the gloss measurement of non-textured coatings on plane, opaque substrates.
Note: On test specimens different from these mentioned above, comparative gloss measurements are possible. However, it is not ensured that the obtained gloss values correspond to the visual gloss perception (see Annex A).
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1514 Paint and varnishes - Standard panels for testing
Note: GB/T 9271-2008, Paints and varnishes standard panels for testing (ISO 1514:2004, MOD)
ISO 2808 Paints and varnishes - Determination of film thickness
Note: GB/T 13452.2-2008, Paints and varnishes - Determination of film thickness (ISO 2808:2007, IDT)
ISO 4618 Paints and varnishes - Terms and definitions
Note: GB/T 5206-2015, Paints and varnishes - Terms and definition (ISO 4618:2014, IDT)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4618 and the following apply.
3.1
gloss
optical property of a surface, characterized by its ability to reflect light specularly
Note: Examples of degrees of gloss are high gloss, gloss, silk gloss, semigloss, satin, matt, and dead matt.
[SOURCE: ISO 4618:2014, 2.132]
3.2
geometry
identification of a method of gloss measurement using a specified angle with assigned apertures
3.3
gloss value
ratio multiplied by 100 of the luminous flux reflected from a specimen to that reflected by a glass surface with a refractive index of 1.567 at a wavelength of 587.6 nm in specular direction for a specified reflection angle and specified aperture angles of light source and receptor
Note 1: The gloss value is indicated in gloss units (GU). It is not permitted to interpret and express gloss values as "% reflection".
Note 2: Gloss values measured on coatings are expressed rounded to the nearest integer (without decimals).
Note 3: To define the gloss scale, polished black glass with a refractive index of 1.567 at a wavelength of 587.6 nm is assigned to the value of 100 for 20°, 60° and 85° geometries.
Note 4: A glass surface with a reflective index of 1.567 at a wavelength of 546.1 nm (which is the central wavelength of the spectral luminous efficiency function) may be used.
Note 5: The gloss value is influenced by the surface characteristics, e.g. roughness, texture, structure, of the sample.
4 Principle
With a reflectometric apparatus, gloss values are determined on coated surfaces, correlating with the visual gloss perception. In this context (glossmeter), the ratio of the gloss of the coating and the gloss of a polished plane glass plate with specified reference refractive index is obtained.
The method of gloss measurement is specified by the following parameters:
——measuring angles;
——field stop apertures;
——spectral adaptation;
——reference refractive index.
5 Basic principles of the gloss measurement
Gloss is a visual perception caused by looking at surfaces. The specular reflection of objects is even more distinct when light is reflected more directionally from the surface. The incident light is reflected on high-gloss surfaces only in the main specular direction. On matt surfaces the light is not only reflected in the main specular direction but also diffusely scattered in all solid angles. The more uniformly the light is scattered into the space the smaller is the intensity of the directed component and the matter the surface appears.
Contents of GB/T 9754-2025
Contents
Foreword I
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Basic principles of the gloss measurement
6 Apparatus and calibration equipment
6.1 Glossmeter
6.2 Measurement standards (certified reference material, working measurement standards) 1)
7 Test panels
7.1 Substrate
7.2 Preparation and coating
7.3 Drying and conditioning
7.4 Thickness of coating
8 Calibration and adjustment of the glossmeter
8.1 Preparation of the apparatus
8.2 Zero point check
8.3 Calibration and adjustment
9 Procedure
9.1 Selection of geometry
9.2 Gloss measurement
10 Precision
10.1 General
10.2 Repeatability limit
10.3 Reproducibility limit
11 Test report
Annex A (normative) Possible sources of error
A.1 General
A.2 Topographical effects
A.3 Geometrical effects
A.4 Optical effects
A.5 Physical effects
Annex B (normative) Calibration standards
B.1 Classification and use of the calibration standards
B.2 Production of calibration standards
B.3 Handling of the calibration standards
Annex C (informative) Gloss calculation of primary reference standards
C.1 Physical basis
C.2 Gloss calculation
Annex D (informative) Details on precision
D.1 General remark on the interlaboratory test
D.2 Samples
D.3 Glossmeters
D.4 Number of measurements
D.5 Expression of results
Bibliography
