Results of a two-component ‘bulge+disc’ fit to a galaxy. The surface brightness in the g band is shown as a function of radial distance from the centre (along an arbitrary angle). The black points are the radially sampled points from the corresponding isophote map for this galaxy, with 3σ error bars. The coloured lines (green and red) represent the fitted intrinsic profiles for each component in the ‘Bulge+Disc’ model. The shaded red region shows the 3σ confidence interval for the combined model, convolved with the PSF. The top panel has no bulge truncation and converges on a non-physical solution. The bottom panel shows a fit using the same initial conditions, but with bulge truncation active during the fitting procedure. The dotted black line in the bottom panel marks the defined boundary between the bulge and the disc.