# Lambert's Cosine Law

### Ideal diffuse reflectors = Lambertian reflectors

Ideal diffuse reflectors reflect light according to Lambert's
cosine law, (these are sometimes called Lambertian reflectors).

### Law : reflected energy from a small surface area in a particular direction
is proportional to the cosine of the angle between that direction and the surface
normal

Lambert's law states that the reflected energy from a
small surface area in a particular direction is proportional to the cosine of
the angle between that direction and the surface normal. Lambert's law determines
how much of the incoming light energy is reflected.

### Reflected intensity is independent of the viewing direction, but dependent
of the source orientation.

Remember that the amount of energy that is reflected in
any one direction is constant in this model. In other words, the reflected intensity
is independent of the viewing direction.

The intensity does, however, depend on the light source's
orientation relative to the surface, and it is this property that is governed
by Lambert's law.