In the field of optics, diffusion refers to situations that cause parallel rays of light to spread out more widely.  When light undergoes diffusion it becomes less concentrated.

  • Diffusion results from any medium or material that scatters light during refraction, reflection or transmission.
  • Scattering takes place when streams of photons (or waves of light) are deflected in different directions.
  • Diffusion of light is a common phenomenon encountered in various real-world scenarios, such as when light passes through frosted glass, paper, or a cloudy sky.
  • Diffusion is responsible for softening shadows and reducing harsh contrasts in photography, making it particularly useful in portrait and product photography.
  • All objects obey the law of reflection on a microscopic level. If the irregularities on the surface of an object are larger than the wavelength of light, the light undergoes diffusion.
  • Transparent and translucent materials transmit diffuse light unless their surfaces are perfectly flat and their interiors are free of any foreign material.
  • When diffuse light falls on an object or scene it produces softened effects without sharp detail.
  • A mirror-like reflection free of the effects of diffusion is called a specular reflection.