Texture Shadows, caused by variation in surface texture, create contrast that allows the viewer to perceive depth in a material. The position of the light source determines the length of shadow; rendering the surface with varying degrees of definition.
Surface Reflectance: how an opaque material reflects light, determines the viewer's perception of the illumination present at it's surface. While a mirrored, or highly specular surface is most able to reflect the view. It will appear dark if the environment seen in reflection is not illuminated; even if light is present on the surface. Matte or diffuse materials reflect light equally in many directions, resulting in a similar light quality from many points of view.
Lighting and Color: every object absorbs some of the light that strikes it. The pigment within a surface determines how much and which components of the visible spectrum reach of the eye. Generally speaking, dark colors absorb more illumination than their lighter counterparts.
Light Transmission: transparent and translucent materials allow light to pass through them. The internal composition of these materials influences the amount and quality of light transmitted.