  We study all possible sources of inaccuracy in theoretical values of the
photometric observables, i.e. amplitude ratios and phase differences, of early
B-type main sequence pulsators. Here, we discuss effects of parameters coming
from both models of stellar atmospheres and linear nonadiabatic theory of
stellar pulsation. In particular, we evaluate for the first time the effect of
the departure from the LTE approximation. The atmospheric input comes from
line-blanketed, LTE and NLTE plane-parallel, hydrostatic models. To compute the
limb-darkening coefficients for NLTE models, we use the Least-Square Method
taking into account the accuracy of the flux conservation. We present effects
of NLTE atmospheres, chemical composition and opacities on theoretical values
of the photometric observables of early B-type pulsators. To this end, we
compute tables with the passband fluxes, flux derivatives over effective
temperature and gravity as well as the non-linear limb-darkening coefficients
in 12 most often used passbands, i.e. in the Str\"omgern system, $uvby$, and in
the Johnson-Cousins-Glass system, $UBVRIJHK$. We make these tables public
available at the Wroc{\l}aw HELAS Web page, http://helas.astro.uni.wroc.pl.
