Corrected peak magnitudes (as provided by the Pantheon+ dataset) of 42 calibration supernovae relative to distance moduli from Cepheids, as a function of the mean reddening E(B − V) conditioned on supernova colour and based on the Pantheon+ dust model (see Appendix C). The filled circles (half-filled triangles) show 27 (15) supernovae for which Pantheon+ applies extinction correction with R_B = 3.1 (R_B = 4). The plot also shows two samples of calibration galaxies from Freedman et al. (2025) and Perivolaropoulos & Skara (2023), which result in systematically lower best-fit values of the Hubble constant than the SH0ES result. It is apparent that both samples minimise the contribution from reddened supernovae or those with R_B = 3.1.