The colour of the surface of an element has a significant effect on its thermal behaviour under (solar) radiation. Highly reflective surfaces (eg polished aluminium) allow the transmission of very little heat, while dark surfaces absorb a large proportion of the radiation that falls on them. White surfaces reflect a high proportion at visible frequencies (but much less at low frequencies). Black surfaces absorb nearly all incident (incoming) wavelengths. Coloured surfaces, even those which appear light in colour, behave more like black than white surfaces. (See reflectivity, emissivity).