Neon Color Spreading to Two Dimensional Manifolds and Three Dimensional Solids

Abstract

Varin (1971) and van Tuijl (1975) described a striking color illusion/effect (neon color spreading) (NCS)): Consider thin rectangular spokes radially emanating from a central point such that the inner ∼1/3 is red while the remainder of each spoke is black. There is the vivid perception of a filled in red disc (radius the length of the red portion of the spokes). We wondered if NC could be made to spread into three dimensional figures. Many initial attempts were in vain: Using red/black spokes as in the original effect such that perspective caused one to perceive the surface of a sphere–not just a disc–we did not see neon color spread to this surface, even when this was enhanced with stereo fusion. Even when we used stereo and multiple perspective cues to have color spread to the surface of a small sphere inside a cube we did not see spreading to the sphere, just the perception of a planar colored disc. Using stereo and a color spreading effect (Huang et al, VSS Demo Night 2010) we were finally able to obtain NCS to planes coming out of the screen/page, and we were also able to obtain NCS to two-dimensional manifolds (e.g., the surface of a torus) using modal/amodal completion figures of Tse (1998). Liinasuo et al. (2000) noted figures in which they saw NCS onto two-dimensional manifolds, but we see the manifolds without the NCS. Using the watercolor effect Tanca and Pinna (2008) were able to get NCS to two-dimensional manifolds. We were able to achieve NCS into three- dimensional solids using stereo and the watercolor effect, the interior “blob” figures set so as delineate the surface and interior locations of a sphere. These investigations raise consciousness generally about the perception of three-dimensional solids.