Fitted i − H gradients plotted against the fitted g − r gradients. The error bars denote the standard errors (see text). Galaxies with g − r gradients larger than 0.10 mag/R_eff are defined as quantitative blue-cored early-type dwarf galaxies and are located above the black horizontal tick in the plot. Galaxies that were classified as non-dwarfs by Binggeli et al. (1985) are displayed as filled grey circles. The colour-coding on the y-axis defines the ranges of four subsamples that all include the same number of galaxies (30). The fraction f of galaxies in the g − r gradient distribution is presented in the right histogram.