AmbientLight is an option for Graphics3D and related functions that gives the level of simulated ambient illumination in a three-dimensional picture.
The setting for AmbientLight must be a GrayLevel, Hue or RGBColor directive.
See the Mathematica book: Section 2.9.12.
See also: Lighting, LightSources, SurfaceColor.
The first plot uses GrayLevel, the default setting for AmbientLight; the second plot uses Hue.
Evaluate the cells to compare the plots.