How is light scattered?

When light strikes particles it may be scattered. When the scattering particles are extremely small (to the order of 1000 nm) the light is scattered according to a simple law proposed by Rayleigh: short wavelengths are scattered more than long wavelengths. For larger particles (to the order of 4000 nm and larger) the amount of scattering is according to Fresnel's equations: the amount of scattering depends upon the difference between the refractive index of the particle and of the medium in which it is dispersed and this difference is wavelength dependent.

If light is scattered evenly in all directions this is called isotropic scattering but it is rarely the case. The absorption and scattering properties of partices are complex and a number of theories exist to describe them including the Kubelka-Munk theory.