I think my brain did a defragmentation of the hard drive overnight. I woke up remembering something about how the Greeks had come up with a mathematical view on this subject. I believe the 35mm format was a "natural" format. Can anyone shed some light on this?

I would like to print photographs in a format that fits in with our field of view. Believing that someone at an exhibition looking at the image would feel comfortable with it on a subconscious level.