File talk:Optical.greysquares.arp.jpg
This image originated from en.wikipedia.org. List of contributors:
- [2004-01-07T14:33:28Z] Arpingstone (Optical illusion (grey squares))
- [2004-01-07T14:34:00Z] Arpingstone (Optical illusion (grey squares))
- [2004-05-06T06:09:26Z] Bryan Derksen (copy over description from thumbnail)
- [2004-05-06T08:58:26Z] Arpingstone (Easier method)
- [2004-05-06T09:01:42Z] Arpingstone
- [2004-05-12T11:59:18Z] 80.146.51.67
- [2004-05-12T17:53:32Z] Arpingstone (Sorry, but your extra comparison method is pointless because the first comparison method ("Click the large picture" etc.)says exactly the same thing!)
- [2004-07-29T10:34:58Z] MichaelMcGuffin (attribution to Adelson)
- [2004-10-06T21:25:45Z] Quadell ({{CopyrightedFreeUse}})
- [2004-10-17T23:35:06Z] Evercat (note other version)
- [2004-10-18T17:04:50Z] Arpingstone
- [2004-10-21T23:39:01Z] Toytoy (a comparison of two pictures)
- [2004-10-22T00:12:41Z] Toytoy
- [2004-10-23T19:12:03Z] 172.172.104.66
- [2004-10-24T22:03:40Z] 65.161.65.84
- [2004-10-28T08:04:22Z] Solitude ({{FeaturedPicture}})
- [2004-11-16T09:54:12Z] 195.33.105.17 (example of proof)
- [2005-01-29T05:43:25Z] 24.34.73.163 (added link to a demonstration of the match between A and B)
- [2005-01-29T05:51:30Z] 24.34.73.163 (added a reference to two additional matching squares)
- [2005-01-29T06:01:10Z] 24.34.73.163 (more matches to B)
- [2005-02-14T14:47:49Z] 141.70.124.34
- [2005-11-04T10:38:42Z] Kriegman (fixed broken link)
- [2005-11-04T10:39:58Z] Kriegman
- [2006-03-19T08:14:58Z] Tawkerbot (subst'ing {{FeaturedPicture}} per request of Pegasus1138)
- [2006-03-19T10:12:41Z] Tawker (Reverted edits by [[Special:Contributions/Tawkerbot|Tawkerbot]] ([[User talk:Tawkerbot|Talk]]) to last version by Kriegman)
Original title:
- Optical.greysquares.arp.600pix.jpg
Upload log:
- (del) (cur) 16:08, 22 June 2005 . . Chameleon (Talk | contribs) . . 507×380 (49,238 bytes) (Cropped a large amount of white space and made image conform to 3:4 aspect ratio.)
- (del) (rev) 09:39, 6 May 2004 . . BillyH (Talk | contribs) . . 600×465 (47,135 bytes) (Better quality and smaller filesize version of image.)
- (del) (rev) 14:33, 7 January 2004 . . Arpingstone (Talk | contribs) . . 600×465 (66,857 bytes) (Optical illusion (grey squares))
Text:
{{NowCommons|Image:Optical.greysquares.arp.jpg}} Prepared for Wikipedia by [[User:Arpingstone|Adrian Pingstone]] in January 2004. No matter how hard you look, you may not be able to convince yourself that the two squares ''are'' the identical shade of grey (I can't). To check, try one of these methods: # Right click the large picture, save it to your hard drive, put it into your image editor, "select" square A and then pull it down onto square B. ''There will be an exact match in colour!'' An example of this proof can be seen at [[:de:Bild:Optical greysquares proof.png]] # [--www.yoism.org/?q=node/74 This presentation] of the illusion is linked to an animated GIF that demonstrates the color match. That animation demonstrates that B is also an exact match to the two "dark" squares straddling the corners closest to and farthest from the viewer (A is one of the latter two). Furthermore, it makes it clear that none of the "light" colored squares matches B (though the one diagonally touching B to the left comes close). # As above but use the Color Sampler Tool or whatever means you have of sampling the RGB values of a point on the picture. Both squares produce the same RGB values. I got value 106. [[JPEG]] artifacts may cause slight variation. # Right click the large picture, choose Print, then cut out square A and position it on square B. #Easiest of all, get a piece of paper and cut windows in it so that only squares A and B are showing through! "©1995, Edward H. Adelson. These checkershadow images may be reproduced and distributed freely." --web.mit.edu/persci/people/adelson/checkershadow_illusion.html {{CopyrightedFreeUse}} There is an alternate picture showing the same effect at [[:Image:Gray_square_illusion.png]]. {{FeaturedPicture}}
