Colorecho

Colorecho is a term that describes the phenomenon where colors appear to reverberate or persist in one's vision after viewing a strongly colored object for a prolonged period. This afterimage effect is a common visual experience and is related to the way our eyes and brain process color. When photoreceptor cells in the retina, specifically the cone cells responsible for color vision, are overstimulated by a particular color, they become temporarily less sensitive to that color.

When the gaze is then shifted to a neutral surface, such as a white wall, the brain interprets the reduced sensitivity to the original color as the presence of its complementary color. For example, staring at a red object and then looking away might produce a green afterimage, as green is the complementary color to red. This happens because the cone cells that were fatigued by the red light are less responsive, while the other cone cells (sensitive to green and blue) are functioning normally, leading the brain to perceive the absence of red as green.

Colorecho is a benign and temporary visual illusion. It is not indicative of any underlying visual problem and typically fades within a few seconds. The intensity and duration of the colorecho can vary depending on the saturation and brightness of the original color, as well as the duration of exposure. This phenomenon is a fundamental demonstration of how our visual system adapts to stimuli and processes information.