Fechner color
Encyclopedia
The Fechner color effect is an illusion
of color
seen when looking at certain rapidly changing or moving black-and-white patterns. They are also called pattern induced flicker colors (PIFCs). Not everyone sees the same colors.
The effect is most commonly demonstrated with a device known as Benham's top
. It can also be seen in stroboscopic lights
when flashes are set at certain critical speeds. Rotating fan blades, particularly aluminium ones, can also demonstrate the effect; as the fan accelerates or decelerates, the colours appear, drift, change and disappear. The stable running speed of the fan does not (normally) produce colours, suggesting that it is not an interference effect with the frequency of the illumination flicker.
The effect was noted by Gustav Fechner
and Hermann von Helmholtz
and propagated to English-speakers through Charles Benham
's invention of his top
. The perceptual
mechanism of Fechner color is not entirely understood.
When the disk is spun, arcs of pale color are visible at different places on the disk. One possible reason people see colors may be that the color receptors in the human eye respond at different rates to red, green, and blue. Or, more specifically, that the latencies of the centre and the surrounding mechanisms differ for the different types of color-specific ganglion cells.
The phenomenon originates from neural activity in the retina
and spatial interactions in the primary visual cortex, which processes pattern recognition. (von Campenhausen & Schramme, 1995) Research indicates that the blue-yellow opponent process
accounts for all the different PIFCs. (Schramme, 1992)
Illusion
An illusion is a distortion of the senses, revealing how the brain normally organizes and interprets sensory stimulation. While illusions distort reality, they are generally shared by most people....
of color
Color
Color or colour is the visual perceptual property corresponding in humans to the categories called red, green, blue and others. Color derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors...
seen when looking at certain rapidly changing or moving black-and-white patterns. They are also called pattern induced flicker colors (PIFCs). Not everyone sees the same colors.
The effect is most commonly demonstrated with a device known as Benham's top
Benham's top
Benham's top, also called Benham's disk, is named after the English toymaker Charles Benham, who, in 1895, sold a top painted with the pattern shown. When the disk is spun, arcs of pale color — called Fechner colors or pattern induced flicker colors — are visible at different places...
. It can also be seen in stroboscopic lights
Stroboscope
A stroboscope, also known as a strobe, is an instrument used to make a cyclically moving object appear to be slow-moving, or stationary. The principle is used for the study of rotating, reciprocating, oscillating or vibrating objects...
when flashes are set at certain critical speeds. Rotating fan blades, particularly aluminium ones, can also demonstrate the effect; as the fan accelerates or decelerates, the colours appear, drift, change and disappear. The stable running speed of the fan does not (normally) produce colours, suggesting that it is not an interference effect with the frequency of the illumination flicker.
The effect was noted by Gustav Fechner
Gustav Fechner
Gustav Theodor Fechner , was a German experimental psychologist. An early pioneer in experimental psychology and founder of psychophysics, he inspired many 20th century scientists and philosophers...
and Hermann von Helmholtz
Hermann von Helmholtz
Hermann Ludwig Ferdinand von Helmholtz was a German physician and physicist who made significant contributions to several widely varied areas of modern science...
and propagated to English-speakers through Charles Benham
Charles Benham
Charles Edwin Benham JP was a journalist, editing for many years the Essex County Standard, a published author of works such as Essex Ballads and an amateur scientist-cum-inventor, which led him to create Benham's top, which was named after him....
's invention of his top
Benham's top
Benham's top, also called Benham's disk, is named after the English toymaker Charles Benham, who, in 1895, sold a top painted with the pattern shown. When the disk is spun, arcs of pale color — called Fechner colors or pattern induced flicker colors — are visible at different places...
. The perceptual
Perception
Perception is the process of attaining awareness or understanding of the environment by organizing and interpreting sensory information. All perception involves signals in the nervous system, which in turn result from physical stimulation of the sense organs...
mechanism of Fechner color is not entirely understood.
When the disk is spun, arcs of pale color are visible at different places on the disk. One possible reason people see colors may be that the color receptors in the human eye respond at different rates to red, green, and blue. Or, more specifically, that the latencies of the centre and the surrounding mechanisms differ for the different types of color-specific ganglion cells.
The phenomenon originates from neural activity in the retina
Retina
The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical...
and spatial interactions in the primary visual cortex, which processes pattern recognition. (von Campenhausen & Schramme, 1995) Research indicates that the blue-yellow opponent process
Opponent process
The color opponent process is a color theory that states that the human visual system interprets information about color by processing signals from cones and rods in an antagonistic manner...
accounts for all the different PIFCs. (Schramme, 1992)