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.