Normalised half-light radius R_half as a function of rest-frame wavelength. We bin the galaxies according to their inclination, and estimate the logarithm of the median spectrum of R_half. Then, we normalise with R_{half, 5000 Å}. We exclude the elliptical galaxies from this plot, as the effects by dust are negligible. The dashed orange line represents the dependence of size on wavelength for a disk population, and by taking into account the effects of dust. The relation was predicted by Pastrav et al. (2013). The vertical red line indicates the location of the Hα emission line.