These are kept soaked in a colored fluid called the retinal purple, which changes under the influence of light, somewhat in the same way that the film on a photographic plate does, thus forming pictures, which are translated by the rods and cones and telegraphed along the fibres of the optic nerve to the brain.
"A Handbook of Health"
Woods Hutchinson
Mike the Angel put his face in the rest for the retinal photos.
"Unwise Child"
Gordon Randall Garrett
Thus, by these methods, using the truth of color in the sense of following the nature of retinal functioning, Monet and his followers raised the color scale many degrees in brightness.
"The Psychology of Beauty"
Ethel D. Puffer