Full data reduction process as applied to the HAT-P-12b observations from the blue CCD. The top panel shows the raw data as they are received after the initial reduction pipeline at the telescope (see Section 3). The second panel shows the results of the blaze correction and cosmic-ray filtering (see Section 3). The third panel shows the data after five iterations of SYSREM have been applied, and the bottom panel shows the standard deviation along each wavelength band of the third panel.