Magnified 400 × 400 arcsec² sub-arrays of the images shown in Fig. 1 for a network (left) and a plage region (right). From top to bottom: (panels a and b) SDO/HMI unsigned (and spatially degraded) magnetogram; (panels c and d) Rome/PSPT Ca II K; the corresponding segmentation masks derived with Method 1, i.e. constant thresholds, from (panels e and f) the magnetograms and (panels g and h) the Ca II K images. The magnetograms are saturated in the range [−300,300] G (the negative value was chosen merely to improve visibility of the pixels), and Ca II K observations in the range [0.5,1.6] (the QS has an average value of 1).