objects are not detected. For them, we adopt 3 times the background uncertainty as an upper limit. Since the sample BCDs are compact enough to be treated as point sources with the resolution of FIS, we follow the point-source photometry described in @verdugo07.

Finally [the same colour correction as in H08 was adopted]{} for the *WIDE-L* ($140~\mu$m) fluxes: the colour correction factor was assumed to be 0.93 (the flux was divided by this factor). We did not apply colour correction to the *N60* (65 $\mu$m), *N160* (160 $\mu$m), and *WIDE-S* ($90~\mu$m) fluxes, following H08. For these three bands, the uncertainty caused by not applying colour correction is smaller than the errors put in Table \[tab:flux\].

FIR colours
-----------

The FIR colours are defined by the flux ratio between two bands (Section \[subsec:colour\]). HHS07 investigated the FIR colours of the Milky Way and the Magellanic Clouds by using the Zodi-Subtracted Mission Average (ZSMA) taken by the Diffuse Infrared Background Experiment (DIRBE) of the *Cosmic Background Explorer* (*COBE*). Details of the observational data analysis can be found in @hibi06, who adopted DIRBE bands of 60 $\mu$m, 100 $\mu$m, and 140 $\mu$m and two colours, 60 $\mu$m–100 $\mu$m colour, $(60/100)_\mathrm{cl}$, and 140 $\mu$m–100 