Anti reflective coatings are used to maximise the amount of transmitted light at a glass interface. It does this by causing reflected light to undergoes destructive interference as much as possible.

As shown blow, if the glass is coated with a layer such that the thickness of the layer inthen light reflected at the coating layer interfaceand the coating glass interfacehas a path difference of and destructive interference occurs.

Of course complete destructive interference will only occur for a single wavelength. Because visible light is made up of a range of wavelengths, this will mean that the reflected light appears tinged with colour – the phenomenon known as 'blooming'.