Difference between revisions of "Benham's top" - New World Encyclopedia
({{Contracted}}) |
|||
| Line 5: | Line 5: | ||
[[Image:Benham's_Disc.svg|thumb|right|250px|A sample of a Benham's disk]] | [[Image:Benham's_Disc.svg|thumb|right|250px|A sample of a Benham's disk]] | ||
| − | '''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 at right. When the disk is spun, arcs of pale color | + | '''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 at right. When the disk is spun, arcs of pale color are visible at different places on the disk. |
| − | The phenomenon is | + | ==Discovery== |
| + | The discovery of the phenomenon is generally attributed to C. E. Benham, although [[Gustav Fechner]] and [[Hermann von Helmholtz]] had experimented with similar disks many years earlier. Benham first announced his discovery in ''Nature'', 52:113-144 in 1894, and his "Artificial Spectrum Top" became more commonly known as a "Benham top/disk".<ref>[http://faculty.washington.edu/chudler/benham.html "Benham's Disk"] University of Washington. Retrieved September 7, 2007.</ref> | ||
| − | The | + | ==Description== |
| + | The top of the disk is half black/half white, and the white side has a series of sets of concentric arcs. When the top is spun, the viewer sees a series of concentric circles of varying colors. Different people may not see the same set of colors, and the order of the colors is reversed if the disk is spun in the opposite direction. | ||
| − | + | ==Explanation== | |
| + | Scientists have long been puzzled over the phenomenon. The human [[retina]] is composed of both rods and cones; there are three types of cones that are sensitive to each of three colors of light (red, blue, and green). It is suggested that the colors in the Benham disk may be a result of the different response times of various cones. In this theory, the white part of the disk activates all three cones and the black half deactivates them. Because of the differing response times of the three types of cones, as well as the difference in time they remain activated, an imbalance of information is sent to the brain resulting in the perception of colors. An alternate theory proposes that the spinning black and white areas activate neighboring areas of the retina differently, and the alternating response causes an interaction in the nervous system, generating the colors. The generated colors have variously been referred to as "subjective colors", "Fechner-Benham colors", "polyphan colors", and "pattern-induced flicker colors" (PIFC's).<ref>[http://faculty.washington.edu/chudler/benham.html "Benham's Disk"] University of Washington. Retrieved September 7, 2007.</ref> | ||
| + | Despite these theories, the reason behind the illusion remains a scientific mystery, and no theory yet explains the colors of Benham's disk completely. | ||
| + | |||
| + | ==Applications== | ||
| + | Benham's top and other PIFCs are being researched for use as a diagnostic tool for diseases of the eye and the visual track. It has shown particular promise in detecting [[Optic neuritis]].<ref>Pilz J, Marre E, (1993) "Pattern-induced flicker colors. An ophthalmologic examination method" (Article in German) ''Ophthalmologe'' vol 90 iss 2 pp.148-54. PMID 8490297</ref> | ||
| + | |||
| + | ==Notes== | ||
| + | <references/> | ||
==References== | ==References== | ||
| − | + | *von Campenhausen, C. and Schramme, J., "100 years of Benham's top in Colour Science", Perception, 24:695-717, 1995. | |
| − | + | *Falk, David R., Dieter R. Brill, and David G. Stork, "Seeing the Light: Optics in Nature, Photography, Color, Vision, and Holography", ''Wiley'', November 1986. ISBN 0471603856 | |
| + | *Hoffman, Donald David. "Visual Intelligence: How We Create What We See", ''W.W. Norton & Company'', February 2000. ISBN 0393319679 | ||
== External links == | == External links == | ||
*[http://faculty.washington.edu/chudler/benham.html Benham's Disk] | *[http://faculty.washington.edu/chudler/benham.html Benham's Disk] | ||
*[http://www.michaelbach.de/ot/col_benham/index.html An interactive version] | *[http://www.michaelbach.de/ot/col_benham/index.html An interactive version] | ||
| − | + | *[http://www.biyee.net/v/benham_top/index.htm Another group of interactive disks] | |
Revision as of 18:41, 7 September 2007
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 at right. When the disk is spun, arcs of pale color are visible at different places on the disk.
Discovery
The discovery of the phenomenon is generally attributed to C. E. Benham, although Gustav Fechner and Hermann von Helmholtz had experimented with similar disks many years earlier. Benham first announced his discovery in Nature, 52:113-144 in 1894, and his "Artificial Spectrum Top" became more commonly known as a "Benham top/disk".[1]
Description
The top of the disk is half black/half white, and the white side has a series of sets of concentric arcs. When the top is spun, the viewer sees a series of concentric circles of varying colors. Different people may not see the same set of colors, and the order of the colors is reversed if the disk is spun in the opposite direction.
Explanation
Scientists have long been puzzled over the phenomenon. The human retina is composed of both rods and cones; there are three types of cones that are sensitive to each of three colors of light (red, blue, and green). It is suggested that the colors in the Benham disk may be a result of the different response times of various cones. In this theory, the white part of the disk activates all three cones and the black half deactivates them. Because of the differing response times of the three types of cones, as well as the difference in time they remain activated, an imbalance of information is sent to the brain resulting in the perception of colors. An alternate theory proposes that the spinning black and white areas activate neighboring areas of the retina differently, and the alternating response causes an interaction in the nervous system, generating the colors. The generated colors have variously been referred to as "subjective colors", "Fechner-Benham colors", "polyphan colors", and "pattern-induced flicker colors" (PIFC's).[2]
Despite these theories, the reason behind the illusion remains a scientific mystery, and no theory yet explains the colors of Benham's disk completely.
Applications
Benham's top and other PIFCs are being researched for use as a diagnostic tool for diseases of the eye and the visual track. It has shown particular promise in detecting Optic neuritis.[3]
Notes
- ↑ "Benham's Disk" University of Washington. Retrieved September 7, 2007.
- ↑ "Benham's Disk" University of Washington. Retrieved September 7, 2007.
- ↑ Pilz J, Marre E, (1993) "Pattern-induced flicker colors. An ophthalmologic examination method" (Article in German) Ophthalmologe vol 90 iss 2 pp.148-54. PMID 8490297
ReferencesISBN links support NWE through referral fees
- von Campenhausen, C. and Schramme, J., "100 years of Benham's top in Colour Science", Perception, 24:695-717, 1995.
- Falk, David R., Dieter R. Brill, and David G. Stork, "Seeing the Light: Optics in Nature, Photography, Color, Vision, and Holography", Wiley, November 1986. ISBN 0471603856
- Hoffman, Donald David. "Visual Intelligence: How We Create What We See", W.W. Norton & Company, February 2000. ISBN 0393319679
External links
Credits
New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:
The history of this article since it was imported to New World Encyclopedia:
Note: Some restrictions may apply to use of individual images which are separately licensed.
