Predicted photometric redshifts as a function of spectroscopic redshift color-coded with number density for the baseline method. We compare cases with different numbers of iterations in training using the SDSS data and and the network Net_P. The dashed red lines indicate the boundaries (z_photo - z_spec+ z_spec) = ±0.05 for outliers defined for the SDSS data as in Pasquet et al. (2019) and Treyer et al. (in prep.).