  We study the lamppost model, in which the primary X-ray sources in accreting
black-hole systems are located symmetrically on the rotation axis on both sides
of the black hole surrounded by an accretion disc. We show the importance of
the emission of the source on the opposite side to the observer. Due to
gravitational light bending, its emission can increase the direct (i.e., not
re-emitted by the disc) flux by as much as an order of magnitude. This happens
for near to face-on observers when the disc is even moderately truncated. For
truncated discs, we also consider effects of emission of the top source
gravitationally bent around the black hole. We also present results for the
attenuation of the observed radiation with respect to that emitted by the
lamppost as functions of the lamppost height, black-hole spin and the degree of
disc truncation. This attenuation, which is due to the time dilation,
gravitational redshift and the loss of photons crossing the black-hole horizon,
can be as severe as by several orders of magnitude for low lamppost heights. We
also consider the contribution to the observed flux due to re-emission by
optically-thick matter within the innermost stable circular orbit.
