Stain on texture: perception of a dark spot having a blurred edge on textured backgrounds.When distinguishing illumination from reflectance edges, both edge blurriness and textural continuity across an edge are generally used as cues to promote the illumination-edge interpretation.  However, when these cues were combined, i.e., when a dark spot having a blurred edge was placed on textured backgrounds, we unexpectedly found that the spot appears stained or painted rather than differently illuminated ("stain on texture" phenomenon). 
ROUNDS
Stain on texture: perception of a dark spot having a blurred edge on textured backgrounds.When distinguishing illumination from reflectance edges, both edge blurriness and textural continuity across an edge are generally used as cues to promote the illumination-edge interpretation.  However, when these cues were combined, i.e., when a dark spot having a blurred edge was placed on textured backgrounds, we unexpectedly found that the spot appears stained or painted rather than differently illuminated ("stain on texture" phenomenon). 
ROUNDS