In an earlier post, I wrote about the tradition in painting to place the sitters so that the right side of the sitter’s face receives the main light. A common theory is that right handed painters working by window light would use such a setup to avoid shading the canvas with their hand. This is a very practical assertion, but the reason may be more fundamental that an early traditon established by right handed painters.
A recent episode of PBS Nova called Dogs Decoded, about the relationship between dogs and humans, researchers made an interesting comment about a discovery by physical anthropologists about how we read emotion. The theory is that humans display emotion primarily on the right side of the face. Furthermore, when eye movement is tracked, humans always scan eachother’s faces left to right (reading the person’s right side first). This may explain why portraits made with a main light to the sitter’s right or centered above feel more natural and engaging than the reverse. It turns out that dogs also always scan human faces from left to right, so the assumption that they can read our moods.
Lighting from below, known as “Frankenstein Lighting” yeilds the most unsettling emotional impact.