Top: multi-colour light curve of AT 2019abn, with: u′, purple; B, blue; V, green; r′, orange; i′, red; z′, grey; H, black (they appear on the light curve from faintest to brightest in that order). The J-band photometry is in cyan, with K_s-band in magenta. Bottom: (B − V) and (r′−i′) colour evolution (again in AB mags) of AT 2019abn, compared to that of AT 2017be. The photometry for both objects is corrected for Galactic reddening only (E_B − V = 0.03 and E_B − V = 0.05 mag respectively), and Vega BV mags are converted to the AB system using Bessell et al. (1998).