Color-magnitude diagrams for the optical and NIR photometry. The circle and square symbols are the REM and LCOGT observations, respectively. The colors indicate the different stages of the light curve, where black is the pre-burst quiescence, pink is the brightening phase, green is the dimming phase, and gray is the post-burst quiescence (cf. Sect. 4.1). The arrow is the A_V = 1.1 mag extinction vector following the extinction curve of Cardelli et al. (1989). The dotted horizontal lines indicate the ɡ = 12.5 mag threshold indicative of when EX Lupi is in burst.