Is Galactic dark matter white?

We calculate the expected white dwarf luminosity functions and discovery fu nctions in photometric passbands, assuming that these stellar remnants prov ide a substantial fraction of the sought Galactic dark matter, as suggested on various observational grounds. We demonstrate the extremely rapid varia tion of the photometric signature of halo white dwarfs with time and thus t he powerful diagnostic of white dwarf colors to determine the age of the Ga lactic halo. We also consider the various indirect constraints implied by a white dwarf-dominated halo. These calculations will guide present and futu re observational projects at faint magnitudes. This will enable us to deter mine not only the nature of the Galactic dark matter but also the age and t he initial conditions of Galaxy formation.