ISO 2813 Paints and Varnishes - Determination of Gloss Value at 20, 60 and 85 Degrees

Material Testing

ISO 2813 Paints and Varnishes - Determination of Gloss Value at 20, 60 and 85 Degrees

EUROLAB laboratory provides testing and compliance services within the scope of ISO 2813 standard. The ISO 2813 standard, developed by the International Organization for Standardization (ISO), specifies a method for determining the gloss of coatings using three geometries of 20°, 60° or 85°. The method is suitable for gloss measurement of non-textured coatings on flat, opaque surfaces.

ISO 2813 Paints and Varnishes - Determination of Gloss Value at 20, 60 and 85 Degrees

Comparative gloss measurements are possible on test samples other than those mentioned above. However, it is not ensured that the obtained brightness values ​​correspond to the visual brightness perception.

Luminosity value ratio is the ratio of the luminous flux reflected from a sample multiplied by 587,6 to that reflected by a glass surface with a refractive index of 1,567 at a wavelength of 100 nm in the specular direction for a given angle of reflection and certain aperture angles of the light source and receiver.

Brightness values ​​are determined in relation to the visual brightness perception on surfaces coated with a reflectometric apparatus. In this context (gloss meter), the ratio of coating gloss to gloss is obtained of a polished plane glass sheet with the specified reference refractive index. The gloss measurement method is determined by the following parameters:

  • measuring angles;
  • Field stop openings;
  • Spectral adaptation;
  • Reference refractive index.

Gloss is a visual perception that results from looking at surfaces. The specular reflection of objects is even more pronounced when the light is reflected more directionally from the surface. Incoming light is reflected only in the main specular direction on high-gloss surfaces. On matte surfaces, light is not only reflected in the main specular direction, but diffusely scattered at all solid angles. The more evenly the light is scattered in space, the smaller the density of the directed component and the matter from which the surface appears.

The principle of gloss measurement is based on the measurement of directionally reflected light. In this context, its intensity is measured in a defined angular area around the angle of reflection. The intensity of the reflected light depends on the surface material and the incident angle. Accordingly, more light is reflected on the coated surfaces with increasing incidence angle. The remaining light is refracted at the air/coating interface and diffusion or absorption of light occurs within the coating.

Gloss values ​​are not related to the intensity of incident light, but to the reflective properties of a black, polished glass standard with a specified refractive index.

The perception of brightness can vary greatly for different viewing angles. For example, matte surfaces may appear shiny under light stripping and low viewing angles, because under these reflection conditions a lot of light is directionally reflected and also the diffusion density is low.

Among the services provided by our organization within the framework of material testing services, there are also ISO 2813 standard tests. Do not hesitate to contact our laboratory EUROLAB for your testing and certification requests.

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