  We calculate the uvby light curves of the helium-strong chemically peculiar
(CP) star HD 37776. Assuming that the chemical peculiarity influences the
monochromatic radiative flux due to mainly the bound-free processes and using
the model of the surface distribution of helium and silicon on HD 37776, as
derived from spectroscopy, we calculate the emergent fluxes for a series of its
rotational phases. We show that it is possible to consistently simulate light
curves of a chemically peculiar star and that the basic properties of
variability of helium CP stars can be understood in terms of the model of spots
with a peculiar chemical composition.
