Figure 3. The structural color paintings on curved surfaces.

(a, b) photographic images of structural color painting on a mug. On a PDMS-coated mug, a PS particle powder (1 μm in diameter) was rubbed. The colors changed according to the viewing angle. (c) A schematic for observing diffraction from a concave hemisphere with assembled particle monolayer on its surface. (d, e) Color difference depending on the viewing distance (d). The color looks differently; concentric rainbow at short distance at d = 10 cm (d), but a blue monocolor at d = 40 cm (e). (f) Photographic image of the diffraction colors from concave hemisphere array, shown from the front at d = 40 cm (f) and from tilted angle (θ = 30°).