Dark colours are good absorbers of …

Well dark colours are good  heat because they are good absorbers of light well an object appears dark only when it absorbs all the light falling on it for eg suppose u have a blue pen well reason why u see pen as blue because it absorbs the wavelenghts of other colour light ( consisted in white light) and it reflects blue colour light hence we see the pen as blue
but in case of black body it absorbs all the light of different wavelength and nothing is reflected .
well not the question arises what happened to the absorbed light ? well we know that even light has got some energy and moment it is absorbed by a black body it doesnt dissappear it is transformed into another form of energy like it is retained within the body which in trurn raises the body temperature and some body radiate energy absorbed by light .
Hence a darker body is good absorber of light so as a result it is a good emmitor of heat