Top: multi-colour light curves of SN 2019bkc from ZTF, ATLAS, LT, GROND, and NTT. NIR observations are from GROND and the LT. The grey dashed lines denote spectroscopic observations. Bottom: colour evolution in u − g (blue), g − r (green), r − i (orange), and i − z (red). The dashed line is the g − r colour curve of the Sim et al. (2012) low-mass edge-lit double detonation (ELDD-L) model and SN 2019bkc is seen to be significantly bluer than this model. Also shown are the g − r and r − i colour curves of iPTF16hgs (De et al. 2018b) and SN 2010et (Kasliwal et al. 2012), with the latter requiring interpolation to match the observed dates.