Context : Aims : “ Earthshine ” is the dim light seen on the otherwise dark side of the Moon , particularly when it is close to new . “ Earthlight ” , or reflected sunlight from the Earth , is the source of Earthshine . Using B and V band CCD images of both the dark and bright side of the Moon , we aim to estimate the Johnson photometry B - V colour of the Earthshine for the first time since the late 1960s . From these measurements we are also able to quantify the colour of Earthlight . Methods : We present images of the Moon taken with a small refractor in Hawaii , in B and V bands and taken under favourable conditions so that scattered light in both bands almost completely cancels , yielding a map of the surface in B - V colour . Co-addition of 100 such images taken in rapid succession substantially improves the signal to noise ratio , and several sources of photometric bias are eliminated by use of relative methods . Results : The earthlit dark side of the Moon is observed to be 0.150 \pm 0.005 mag bluer in B - V than the sunlit bright side , in good agreement with the only known previous measurement of this quantity from 1967 . Arguing on the basis of the change in B - V for sunlight reflected once off the Moon , we derive a colour for earthlight of B - V = 0.44 \pm 0.02 mag ( without applying a small , uncertain , phase-dependent reddening correction ) . The absence of a colour-gradient in the B - V image implies that the scattering properties of the atmosphere+optical system are almost exactly matched in the two wavelength bands , the consequences of which are discussed . Conclusions :