Polarised light images of HD100546 from SPHERE/IRDIS. Panel a: the Q_ϕ image in the J band. Panel b: the U_ϕ image in the J band. Panel c: unsharp masking of the Q_ϕ image in the J band (see text). The inner box defines the region displayed in the bottom row. Panel d: labelled version of panel c. The inner inset circle is from panel g. Panel e: inner detail of the Q_ϕ image in the J band. Panel f: inner detail of the Q_ϕ image in the K band. Panel g: unsharp masking (see text) of panel e. The grey circle indicates the IRDIS control radius at r ≈ 20 × λ∕D (see text). Panel h: unsharp masking (see text) of panel f. Features visible from both panels g and h are labelled. The purple dot indicates the location of CCb from Quanz et al. (2013). In all images, the central star is in the middle of the grey circle, symbolizing the instrument coronagraphic mask. The logarithmic colour stretch is relatively arbitrary and refers to positive values, except in panels a and b where it is the same. North is up, east is left.