Gloss (optics)

Gloss is a visual property of a surface to reflect light completely or partially specular. If a surface is not shiny because they reflect light diffusely, so this is called torpor. Like paint, the gloss is a property, which contributes to the visual appearance of a surface. Gloss is a sensation and therefore dependent on the viewer. To make the gloss of surfaces but technically comparable, one can determine with reflectometers a gloss.

Basics

Gloss arises when both the illumination is concentrated, as also reflects the surface specular. Thus, each point on the surface appear from different viewing angles, different light and reflections change with the movement of the viewer. A surface appears very shiny, when the brightness of a point in binocular vision for each eye varies greatly. In contrast, creates dullness when the surface the light diffusely reflected or there is a global diffuse illumination. In the latter case can not be distinguished whether it is a glossy or a matte finish.

Physically, directed gloss defined as the quotient of and the diffusely reflected portion of the incident on a surface luminous flux. It can be quantitatively determined with a gloss meter.

Changes with the viewing angle, the color of the reflected light, it is called iridescence.

Mica, glitter, glitter effects are one of the special forms of gloss, through local, high-gloss, small surface areas, as is typical for the manifold -mounted crystal faces of the minerals of the mica group, but also for ice or for reflections on fine-textured surfaces such as water, or metal foil Schnipp moose ( glitter) or metal effect pigments in a coating such as metallic paints.

Classification schemes

Paints and varnishes

• Gloss
• Semi-gloss or satin finish
• Matt
• Deep matt

Minerals

In mineralogy descending differentiated according to the strength of the gloss between

Other common descriptions of gloss include semi- metallic luster, porcelain gloss, bad luck shine. Numerous mining names have a characteristic luster of these minerals back such as " galena " at the galena or " chalcocite " the chalcopyrite.

• Examples of the different luster of minerals

Sphalerite ( adamantine )

Intergrowth of malachite and chrysocolla ( greasy )

Quartz ( vitreous )

Prehnite ( pearlescent )

Tiger Eye ( semi-gloss )

Stolzit ( resin or waxy luster )

Aluminite (Matte )

Materials

• Surface coating: gloss paint, matting agents, metal effect pigments, interference pigments, pearlescent pigments