Evolution of the signal in GREGOR/HiFI+ filters (upper panel, blue line indicates the blue continuum at 450.6 nm and red the TiO band) and the far wings of the Fe I 6173 Å line from SDO/HMI (lower panel). The crosses indicate the measured signal in a pixel co-spatial with pixel No. 53 on the IRIS slit. The dotted line indicates the fitted background, which represents the smooth evolution in the quieter period. The dashed regions indicate the time ranges used for the fitting of the smooth background.