Colour (and pseudo-colour) magnitude diagrams for NGC 104. The upper panels show the CMDs for NGC 104, col versus mag_F814W and col3 versus mag_F814W. The red and blue lines are the fiducials used. Lower left panels: rectified RGBs in the normalized col and col3. Lower right panel: resulting PCM, where FG stars are those located below approximately 0.1 in Δcol3 and SG stars above.