Light curves of the optical counterpart of GRB 111209A as observed by GROND and UVOT (this work), with additional R_C data from Nysewander et al. (2011) and Stratta et al. (2013), and F336Wu′g′r′R_C i′z′F125W JHK data from L14. Downward-pointing triangles are upper limits. The different bands are colour-coded and given in the legend; they are offset for clarity by the amount given. The G subscript denotes GROND data. Data in this plot are corrected for the (small) Galactic foreground extinction.