The surface luster or shine of dried paint is created by the ratio of pigment to binder. In the painting industry, this ratio is called the pigment volume concentration (PVC), which is the comparison of the volume of pigment to the volume of binder, and is expressed as a percentage.
A higher PVC results in flatter finishes, while lower PVC will give a finish a glossier appearance. Lower pigment concentrations allow more white light to be reflected by the binder material from the surface, giving it a shiny or wet appearance. Paint manufacturers have five more or less standard ranks of surface luster:
Flat: The most pigment rich of all paints, with a PVC of at least 40 percent or higher.
Eggshell: A step down in pigment concentration from flat paint, with a PVC of 35 to 40 percent
Satin: These paints have a PVC of approximately 30 to 35 percent.
Semi-gloss: Semi-gloss paints are a little less than half as concentrated as flat paints, with a PVC of 25 percent.
Gloss: The glossy paints have a PVC of roughly 15 percent.
Flatter paints are slightly less durable than glossier paints because the flat paints have less of the binder material to form a tough bond with the painted surface. When used in commercial or industrial painting applications, flatter paints tend to be used for interior surfaces, while glossier paints are often reserved for exterior applications.