Four examples of self-calibration from our selected DD calibrators. Cycle 0 is the first image with only DI solutions applied from the in-field calibrator (see Sec. 3.2). Cycle 3 corresponds to the self-calibration image after 3 rounds of scalarphase calibration. After this cycle, scalarcomplexgain calibration is added. This also calibrates for amplitude errors. Cycle 10 shows the result after the 10th self-calibration round. In some cases, the RMS noise (given by σ in the figures) goes slightly up when comparing cycles 3 and 10. This is due to the introduction of amplitude corrections, which can cause slight increases or decreases in the overall local RMS values when for instance larger corrections for stations closer to the Dutch core are obtained. The angular size scale is indicated in the right top corner.