Hexagonally-binned 2D histogram of PAUS-DEEP2 matched galaxies’ photo-z error, normalised by their spectroscopic redshifts and as a function of their LEPHARE rest-frame colour u − i. Shading indicates the log-counts in each cell. For the best 50% of photo-z according to the Qz parameter, we display the 16th, 84th percentiles of the normalised photo-z error for red (blue) galaxies as solid red (blue) horizontal lines. Half the difference between the percentiles is quoted for each as σ₆₈. Dashed lines and bracketed values of σ₆₈ are then for the total sample.