A sample of edge on galaxies with luminosities measured in 4 bands: B I J H. Both the slope and scatter of the relation decreases to the longer wavelengths (the y-range is different in the four plots). The B images are sensitive to different amounts of star formation and reddening, while the near-IR images are relatively insensitive to reddening and track the old population which dominates the mass (i.e. it has a much more consistent mass-to-light ratio).