Steps taken to flatten the background in the I_E image. The panels show: (a) the original I_E image with an east-west gradient visible in the background, (b) the I_E image that has been flattened to match the background properties of the CFHT i′-band image (which is shown in panel e), (c) is the image after the subtraction of a scaled 12µm WISE image (shown in panel f) to remove Galactic cirri and the PSF subtraction has been performed on 75 of the brightest stars in the field of view. Panel (d) shows the final processed I_E image after a 2D first-order polynomial gradient was subtracted from the background. Panel (g) shows only the area of the image that is left unmasked, after the light profile of NGC 1272 has been subtracted. The scaling of the colour map transitions smoothly from logarithmic to linear steps at low fluxes in order to highlight the patterns in the background. All panels show the full field of view of the I_E image.