These colours are different in their character from solid colours, otherwise known as full-pigmented colours. This is due to the fact that the paint is a translucent material. Due to this, the opacity of the paint is gained from the additional metal flakes, usually aluminium that are layered in. Therefore, aluminium or metal flakes can be found lying at all depths within the coating.
This results in reflected light scattering in all directions, giving the finish a sparkle. Due to the content of metal flakes within metallic colours, in order to gain a true match of the coating, not only the colour needs to be matched but also the metal flakes. This process ensures a complete match of both the colour and the metallic finish.