Fig. 3

Structural and optical properties of melanin. (a) Melanosomes in birds have four main structures: nanoparticles (purple), nanorods (red), hollow nanorods (blue), and hollow platelets (green). (Scale bars: 500 nm). Reproduced with permission (Maia et al. 2013). Copyright 2013, The Authors. Published by National Academy of Sciences. (b) Extinction coefficients of eumelanin and pheomelanin in the visible range. Reproduced under the terms of the Creative Commons CC BY license (Stavenga et al. 2012). Copyright 2012, The Authors. Published by the Public Library of Science