Colors simulated with the multilayer model. (a) Red colors simulated with varying thickness (0.1 to 4 μm) of a red pigment layer on top of a white reflector and comparison to red markings of different animals. (b) Phelsuma grandis individual number 1. (c) Simulated colors produced by a 7 μm yellow pigment layer on top of a multilayer interference reflector with varying spacing (40 to 105 nm) between layers of crystals 80 nm thick. Double arrows indicate the spacing measured between crystal layers on the dorsal and neck skin of the individual. (d) Simulated colors produced with varying thicknesses (0 to 7 μm) of a yellow pigment layer on top of a blue reflector.