Photometric comparison between KiDS and SDSS photometry of stars in the KiDS-N area. The colourscale indicates the mean magnitude offset m_KiDS − m_SDSS of high-signal stars u <  20, g <  22, r <  22, i <  20 in every tile. The size of the symbol increases with the FWHM of the PSF. The one outlier in the u-band photometry, tile KIDS_229.0_-2.5_u, is one of the highest-extinction fields in the survey and contains few u-band stars.