Rest-frame colour differences between the fiducial galaxy sample (PROSPECTOR-β) and those obtained modifying one stellar population component at the time (y-axis labels). The coloured widths are the sum in quadrature of COSMOS median photometric errors in the two respective bands to indicate distinguishability on a single galaxy basis. The vertical black bars and the white dots on top of them represent the median values of each rest-frame colour difference. The light red boxes show the interquartile range (75th–25th percentile), while the whiskers represent the 84th–16th percentile ranges.