The surface luster or sheen of dried paint is created by the ratio of pigment to binder. In the paint industry, this ratio is called the pigment volume concentration which is the comparison of the volume of pigment to the volume of binder, and is expressed as a percentage.

Paint manufacturers develope the level of sheens they choose to produce. Unfortunatley, most people don’t realize what has been deemed a “Satin Finish” for one manufacturer may still have a differnt sheen level due to the combination of pigment to binder.  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 usually build  five more or less standard ranks of surface luster:

Matte/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.

Flat 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 surface.