Photographs of green flashes do not preclude a role for physiological effects in these phenomena. While green flashes are certainly <i>not</i> after-images, there is compelling evidence that adaptation in the visual system strongly affects the perceived color of most sunset green flashes. Furthermore, the retinal image of the setting Sun is usually bright enough to bleach most of the red-sensitive photopigment in a few seconds, making the yellow stage of a sunset flash appear green. Even in air so hazy that no green light reaches the eye, a yellow flash may occur and appear green. Many, but not all, visual observations of sunset green flashes are of this yellow flash. The yellow portion of sunset green flashes helps explain their reported durations, which exceed those expected for the appearance of green light alone.
© 2000 Optical Society of America
(010.1290) Atmospheric and oceanic optics : Atmospheric optics
(010.4030) Atmospheric and oceanic optics : Mirages and refraction
(330.1720) Vision, color, and visual optics : Color vision
(330.5310) Vision, color, and visual optics : Vision - photoreceptors
(330.5370) Vision, color, and visual optics : Physiological optics
Andrew T. Young, "Sunset science. III. Visual adaptation and green flashes," J. Opt. Soc. Am. A 17, 2129-2139 (2000)