DIN EN ISO 13803:2015-02

High quality surfaces are expected to have a clear and brilliant appearance. Microstructures can cause a milky appearance. This effect is described as haze. A high gloss surface with microscopic texture has diffused light with low intensity adjacent to the main direction of reflection. The majority of the incident light is reflected in the specular direction which will make the surface appear high glossy with image forming qualities, but with a milky haziness on top of it. The phenomenon haze can be seen on high gloss surfaces only. Therefore, the 20° geometry is used as with a gloss meter. The aperture range of a 20° gloss meter is 1,8°. Two additional sensors next to the gloss detector measure the intensity of the diffused light responsible for haze. Thus, the specularly reflected and the scattered light are measured simultaneously. In order to better correlate with the visual perception, haze is displayed in a logarithmic scale - the lower the haze reading, the better the surface. This International Standard specifies a test method for determining the haze of coatings. The method is suitable for the haze measurement of non-textured coatings on plane, opaque substrates. The use of the 20° geometry means that the method is closely related to the measurement of gloss at 20° in ISO 2813. The application of this method is intended to give improved differentiation between highgloss surfaces, for example in the field of assessment of dispersion characteristics. The committee responsible for this standard is NA 002-00-07 AA "Allgemeine Prüfverfahren für Beschichtungsstoffe und Beschichtungen" ("General test methods for coating materials and coatings") at DIN.