The 'resonant interval' has an equivalent in visual perception which McLuhan dubs 'light through'.
The concept comes from modern art, as McLuhan explains, crediting the idea to French painter André Girard: 'television is like [Georges] Rouault [1871-1958] in providing an image by light through, not by light on. Rouault painted his canvasses as if they were stained glass windows.'1
McLuhan contrasts the film image, in which 'the viewer is the camera', to the TV image, in which 'the viewer is the screen': 'Psychologically', he says, 'there would seem to be a great gulf between these two roles', the eye-as-camera 'superficial' in its experience and the eye-as-screen 'a thing of profundity and depth'.2
Unlike 'light on' the object, which establishes the 'point-of-view', the 'light through' structure promotes 'participation' and 'involvement'.3