Top panel: unfolded spectrum of the hard state of Cygnus X-1 using model (b), i.e. reflection (comptt + cutoff power-law). Following panels: residuals to the fits in unit of standard deviations for models (b), (a, reflection (comptt+ power-law)), and (c, eqpair). The corresponding model parameters are listed in Table 1. The data are from JEM-X (black), ISGRI (red), PICsIT (green and blue), and the Compton mode (cyan).