Results of MBB fits to Herschel and Planck data averaged within 8′ of the centre of the SCUBA-2 fields. The results are shown for absolute surface brightness measurements (frame a) and after subtraction of the local background emission (frame b). The symbols correspond to the band combinations listed in the legend in frame b. The large symbols denote the median values over the fields. In frame a, the contours show the 67% (solid lines) and 95% (dashed lines) confidence regions for 250–500 μm (red) and 250–1380 μm (blue) fits, using error covariance matrices that are the median over all fields. For the SPIRE-only fits, the adopted error estimates clearly overestimate the true uncertainty.