When light is reflected from a rough or unpolished surface, instead of forming a single reflected ray, the many tiny facets of the rough material reflect light in many different directions, causing a diffuse reflection. Unlike specular reflection, which exhibits well-defined angles of reflection, diffuse reflection results in light scattering in a wider range of angles, leading to a blurred and less focused reflection.

To understand this scattering, imagine a rugged mountain range, where light can bounce off the various uneven slopes, ridges, and valleys. These irregularities in the surface distort and disperse the light, directing it in multiple orientations. As a result, the reflected light becomes more widely spread, and you perceive the surface as looking rough or matte.

Rough surfaces don't have the uniform, smooth topography necessary for specular reflection. Consequently, the incoming light is not consistently directed according to the angle of incidence, leading to the scattering of light. The absence of a single concentrated reflection point is a defining characteristic of rough surfaces.

Roughness, whether it's naturally occurring or artificially created, disrupts the regularity of the surface structure. This disruption effectively disarray the trajectory of reflected light, producing a more randomized reflection pattern.