The Sheen material layer can simulate the grazing coloration or rim lighting in fabrics like velvet. It can also simulate layers of dust (figure 1).
Figure 1: A MaterialThe representation of the surface or volume properties of an object. Layer Sheen node added to the Material Layer pin on a Diffuse materialUsed for dull, non-reflecting materials or mesh emitters.
Sheen - The Sheen layer's color.
Roughness - The Sheen layer's roughness. Higher values spread the sheen color to larger parts of the surface.
Affect Roughness - The percentage of roughness affecting subsequent layers' roughness.
Bump - Simulates a relief by using a Greyscale texture interpreted as a Height map for the layer.
Normal - Distorts Layer normals by using an RGB image.
Opacity - Controls the Layer opacity with a Greyscale texture.