I worked on paintings on the floor, and was impressed with the way some of them looked when they were wet.
Sometimes I'd see interference from light bouncing off wetter and dryer parts, amplifying small differences in texture. Some of them looked like lake country at dawn or dusk, with light raking across water and low mountains. And seeing the amplified relief of the physical paint layer over the illusion of the painting was magical at times.
And hard to explain here, though you can get an idea by looking at the (painted) illusion in the lower left of the picture here, then above and to the right in the glare, where light is bouncing off the texture of the paint itself. The two phenomena overlap between and around those spots, and remind me why the word "interference" always comes to mind when I think of this.
I thought there might be a way to preserve the look with varnish, but I'd have to destroy a painting to find out. As it is, this poor picture will have to do.
[ Update: The Image Resurrected from Slide ]