Figure 5. Scattering measured on scales of B. rhinoceros and predicted by the Oren – Nayar model⁵⁶.

(a) Schematic drawing of the experimental setup for the measurement of light scattering. Intensity of scattered light was measured at different angles in respect to the scale surface normal: 0°–80° with an illumination angle at 45°. (b) Raw reflection spectra of a black (black lines) and a pale (grey lines) scale with illumination and detector arranged in the rostro-caudal direction (rc) detected from different angles. The intensity of scattered light is presented in arbitrary units. (c) Comparison between light scattering for a pale scale at 700 nm detected from lateral direction (solid line) and light scattering predicted by the model (dashed line). As fit parameters ρE₀ = 37 and σ = 17.5 were applied. The light scattering intensity has the same units as in (b). (d) Intensity of light scattering for a pale scale at 700 nm detected from caudal (rc, dotted line) and lateral (l, solid line) direction. The intensity has the same units as in (b). (e) Comparison of the light scattering intensity of a pale (y-axis on the left, black line) and a black (y-axis on the right, grey line) scale at 700 nm detected from lateral direction. The intensity has the same units as in (b). (f) Light scattering angular dependence of a black scale detected from caudal (rc, dotted line) and lateral (l, solid line) direction at 700 nm. The intensity has the same units as in (b).