Full-field images with 18 000 × 18 000 pixels with a size of 2″ × 2″. The image before calibration is shown in (a). The difference images, that is, the image before calibration minus the image after calibration, are shown in (b), (c), and (d) for various calibration schemes: (b) calibration with all baselines, (c) calibration excluding baselines shorter than 300 wavelengths, and (d) calibration without excluding short baselines and with a model for the large-scale diffuse structure. Because we subtracted a sky model consisting of only compact sources during calibration, the difference images in a perfect calibration should also show what is being subtracted: the compact sources and their artifacts. However, as we see in (b), we also subtracted or suppressed a significant fraction of the diffuse structure when we included all baselines in the calibration. This suppression is much lower in both (c) and (d).