When Brewster, in 1856, spoke of “flowers suspended in the air” in a stereoscopic space he also was prescient with respect to what I call the dematerialization of the substrate ‘surface’ in stereopsis when he said about this: “It has a silvery transparent aspect…it is more beautiful than the real paper, which is no longer seen, and it moves with the slightest motion of the head.”

This relates directly to what Rood and Dove, Theory of Lustre, 1861 said describing a quality of ‘luster’ caused by the binocular combining (optical mixing) of two different color images:

Dove suggests that the peculiar luster of the deep blue sky is caused by light from different distances falling on the eye; and I found, in fact, in this experiment, that when a surface of dark blue paper is combined with white or light blue paper, the combination strongly reminded me of the soft luster of a cloudless sky.

‘Lustre’ was explored in HOMAGE TO ALBERS and is to color field painting and ‘lustre’ what Monet and Impressionism is to the advent of a new aesthetic I called attention to in my manifesto: “as the new possibilities of binocular color fusion”. In 1972 I wrote the following about this painting:

In dedicating this painting to Albers, I was mindful of many beautiful color harmonies in his series of paintings called ‘Homage to the Square’. What I have done in this painting is to shift the position of the squares in a stereo construction (disparity) so that the squares themselves appear to be situated free of the canvas. It was also my intention to explore the possibilities of the binocular optical mixture (in the mind) of colors and, indeed, I did find that optical mixture of colors does occur (in freevision fusion). Experimenting with a great many colored papers, I have observed that by binocular fusion one can obtain sublety in color mixtures as well as the vibrancy of luster (atmospheric effects). In (this) painting the large green square combines with its turquoise mate to produce a softly vibrant blue-green field. This effect is caused by our optically mixing two different hues of similar value. Suspended over this blue-green field is a square plate having a strong blue tint that hovers above as the nearest figure in space. The inner blue-violet square mates with a red of approximately the same value. This combination produces a very lustrous red-violet that acts as a window below the blue plate mentioned above. It gives this hovering blue plate the illusion that it is (in atmosphere) transparent. Sunk deep in this red-violet is the smaller red-orange and yellow square that appears to penetrate below the level of the canvas and they fuse to produce a glowing yellow-orange. The whole painting, with its two inner warm-color squares surrounded by the cooler field, seems to give the feeling of an interior room that is being (suffused atmospherically with light) illuminated.

(‘On Stereoscopic Painting’ 1974, pp. 103)