Gloss (paint)
In paint technology, the sheen is the glossiness of a paint finish. Glossy and flat (or matte) are typical extreme levels of glossiness of a finish. Glossy paints are shiny and reflect most light in the specular (mirror-like) direction, while on flat paints most of the light diffuses in a range of angles. The gloss level of paint can also affect its apparent colour.
Between those extremes, there are a number of intermediate gloss levels. Their common names, from the most dull to the most shiny, include: matte, eggshell, satin, silk, semi-gloss and high gloss. These terms are not standardized, and not all manufacturers use all these terms.
One manufacturer measures gloss as percentages (at an unspecified angle) and gives:
The sheen or gloss level of a paint is principally determined by the ratio of resinous, adhesive binder which solidifies after drying, and solid, powdery pigment. The more binder the coating contains, the more regular reflection will be made from its smooth surface; conversely, with less binder, grains of pigment become exposed to the surface, scattering the light and providing matte effect. To a lesser extent, gloss is also affected by other factors: refraction index of the pigment particles, viscosity and refraction index of the binder.
An important indicator is pigment-volume concentration (PVC), defined as the ratio of pigment volume and total paint volume:
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