I'm diving into PercepTool and the theory behind it - loving what I'm finding. In setting the stage for the forthcoming full tour and review, I want to pass along some of the philosophy behind the tool. This snippet comes from George DeWolfe's book on black and white printing,
"Behind all the inventions, techniques, and movements in painting and photography lies a fundamental truth about the inherent degree of visual perception involved in each: What the painter represents on canvas is a representation of what is visually perceived, while what the photographer represents in an unaltered image is only what is actually seen, not what it visually perceived. What is seen by the retina of your eye or the sensor of your digital camera represents a quantity of light as it falls on a subject or scene. This quantity of light is known as luminance. Luminance combines both the surface reflective nature of the scene being photographed as well as the illumination falling on the scene. What is visually perceived (and painted by a painter) is a many faceted neural operation that separates reflection and illumination and combines them with edge definition, depth, form, and wholeness—a process that, for the artist, is inherently more “real” than what we take for realism in a photograph."
Some interesting food for thought ...