Flare ribbon observation in different channels at 08:07 UT. Top row: (a) AIA 304 Å, (b) AIA 193 Å and (c) AIA 171 Å channels. Second row: (d) line-of-sight magnetic field from Fe I 6173 Å line saturated at ±500 G, (e) Ca II 8542 Å core and (f) Hα core from CRISP. Bottom row: Si IV 1400 Å SJI, Mg II k 2796 Å SJI and Mg II h 2832 Å SJI from the IRIS telescope. White arrows in panels (a), (e) and (g) point to the location of the flare ribbons. The magnetic field from the SST magnetogram is shown as contours in green and blue at ±500 G. The cyan rectangle in panel (e) corresponds to the FOV, where fine-scale structures are studied. The dark vertical line in the middle of the IRIS images is the spectrograph slit. This figure is associated with an animation that is available online.