Total disk g* magnitude vs. the central surface brightness μ₀ for all detected galaxies. The long‐dashed curves are the envelopes of the selection function defined by the limiting isophotes μ_lim labelled in the legend and the limiting angular size at those isophotes, θ_lim = 24^{﹩\arcsec﹩}. They were calculated using eq. (13). Isolines (dotted) with constant scale length α are overplotted as well. Filled diamonds denote the galaxies from the ISIB96 test sample. Open circles mark the galaxies from this test sample with Sérsic SBPs (n > 1). Crosses show the additional galaxies found in the SDSS fields with the same selection criteria as used to retrieve the test sample. The star symbol at g*_tot ≈ 17.0 mag shows the location of the faintest ghost image detected with our software.