Photometric phase curve for magnesia, carbon soot, and ultra-dispersed quartz measured in the laboratory at the λ = 630 nm in the phase angle range of 0.008°–1.5°. The data points are taken from the figure in Psarev et al. (2007). The intensity is normalized at phase angle 1.5°. The local phase curve constructed from the Imhotep-Ash region of 67P using an OSIRIS close-flyby image in F82 (649 nm) filter is plotted as well (red dots).