When two lights of different colors illuminate a form, the lit areas interact with each other in unexpected ways.
In this oil sketch of a white head maquette, an amber-tinted light shines from below left, while a blue-tinted light comes from almost the opposite angle.
There’s almost no overlap between the regions lit by each of the lights. One light or the other covers almost every surface of the head. There are just a couple of small places untouched by either light: the dark area where the nose meets the eye socket, and the hollows above and below the ear.
This maquette is lit by two colored lights. One is yellow-green, and one magenta. The lights are placed closer together, so the illuminated areas overlap on the top of the head, the brow, and the cheekbone plane. In these shared areas, the colors mix to a pale yellowish white, brighter in tone than the lightest tones in each of two regions lit by one light only.
Here's another casting of the plaster head covered with silver aluminum powder. The surface now has a high level of “specularity” or reflectivity.
What happens with colored light on a reflective surface? Even with three different light sources (green, red-violet, and blue), the lights don’t really mix very much on the planes of the head. Instead, each light source accounts for a separate array of specular highlights.
Remarkably, our brains are able to construct an understanding of form based on these fragmentary bits of information.
But if we remove the color clues (and flop the image for a fresh look), the form is much harder to visualize. The highlights seem like random light spots on a dark head. This illustrates a key recent finding of visual perception researchers, namely that color plays a central role in the brain's active construction of form and depth, and is not—as is often supposed—a kind of extra frosting on perception.
Related GJ posts on
Character Maquettes, link
Studio Lighting Equipment, link.