  The present study focuses on the optical properties of functionalized
surfaces and how the surface geometry impacts them. Physical measurements of
reflected light are required to understand the visual aspect of such surfaces.
Bidirectional Reflection Distribution Function (BRDF) is evaluated in order to
identify and understand physical effects induced by different surface
functionalization. BRDF measurements of high angular resolution allow us to
observe diffraction phenomenon at an unusual scale. Experimental results were
compared to theoretical calculation, and then diffraction effect was confirmed.
This study stresses that diffractive phenomenon could have an impact on visual
aspect even for simple pattern geometry. In the same way, if more complex
periodic patterns are considered, as multistate periodicity pattern for
example, it could rise to important modification of surface visual aspect.
