Left panel: offsets O_ν. We also indicate with crosses estimates at 100 μm obtained summing the offset with LAB data and the residual zodiacal light contamination in IRIS maps as derived by Planck Collaboration XI (2014); estimates for SPIRE data using the SPIRE/HFI offsets from the zeroPointCorrection procedure in HIPE. The dashed line shows the offset derived by the Planck team on zodi-corrected maps (Planck Collaboration VIII 2014). Right panel: fitted gradient in ecliptic latitude E_ν. Crosses show the gradient as derived from the correction described in Planck Collaboration XI (2014). To avoid cluttering, we have slightly displaced some symbols from their exact wavelength.