Typical distribution of J-PLUS galaxies in the plane defined by mean effective surface brightness ⟨μ_e, r⟩ and apparent magnitude, both in the r band. The galaxy subsample illustrated in this plot consists of more than 28 000 objects with a galaxy probability >0.99, taken from eight representative DR1 tiles for which 1.05 <  FWHM <  1.15, and the 5σ limiting magnitude is r ∼ 21.5.