When a diffusing support is covered by a clear liquid, light inter-reflections occurbetween the diffusing support and the liquid–air interface, which induce a lateralpropagation of each incident light pencil around its entrance point (halo effect).This effect is to be considered when the support is not homogeneously colored,e.g., a mosaic of colors at the microscopic scale, as it modifies the global spectralreflectance of the support, thereby its color. The color variation dependsparticularly on the reflective index of the liquid, and the layer thickness.