  We describe a smooth transition from (fully ordered) photonic crystal to
(fully disordered) photonic glass that enables us to make an accurate
measurement of the scattering mean free path in nanostructured media and, in
turn, establishes the dominant role of the density of states. We have found one
order of magnitude chromatic variation in the scattering mean free path in
photonic crystals for just $\sim 3%$ shift around the band-gap ($\sim 27$ nm in
wavelength).
