Color profile of the NGC 4281 and NGC 7049 SDSS (g − i) images used for the dust correction. The central dust rings are clearly identified in the upper left quadrant. The best-fitting linear function obtained from a robust fit is shown in green; the slightly shifted red line is the correction threshold. For NGC 4281, all pixels above the red line and for log(r) < 1.2 (≈16 arcsec) were corrected for dust extinction.