Specular Reflections occur when light bounces off a flat, smooth, reflective surface like a mirror, a car bonnet, a window or the gloss surface of a floor.
They retain a lot of the brightness and colour of the original light. Therefore, they can appear much brighter than their surroundings, leading to patches of ‘blown’ (over-exposed) highlights.
Because they are mirror-like, you can use these reflections to add depth and symmetry to your photographs. Even puddles can give great reflections if the camera is close enough.
Because they are bright, and occasionally take on attractive colours from the surface they’re reflected from, they make good light sources; e.g. sunlight reflecting off windows in city streets.
A POLARIZING FILTER (POLARISER) can be used to darken their appearance considerably in many situations.
DIFFUSE REFLECTIONS occur when light reflects off a rough surface.