Line-of-sight magnetograms of the considered ARs before their emergence (at T = −0.3) in the normalised coordinates. Red stars indicate the determined positions of the polarities. We note that frames are not available for all of the ARs (some were too close to the limb to be considered). Also, the polarity positions were extrapolated from their positions after the emergence. All the subplots were saturated at ±100 Gauss.