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DPChallenge Forums >> Photography Discussion >> So you think you have a CLUE what grey is ?
Showing posts 1 - 14 of 14, (reverse)
06/19/2007 09:56:15 AM · #1
Shades of Grey ... //www.broomeman.com/images/optical_illusion.jpg

This bends my mind ... the illusion is further enforced by making the A white and the B black ... and if you don't believe it ... check it out ... they really ARE the same shade of grey ... this is your brain getting in the way of your eyes ...

A cheap and dirty way of seeing it is masking out everything BUT a corner of each of those squares with masking tape or the likes (do not include the letter designation)

You can always use a free utility like pixie to check or Photoshop to determine the RGB values etc ...

Message edited by author 2007-06-19 10:38:40.
06/19/2007 10:07:42 AM · #2
wow, that was pretty amazing!
06/19/2007 10:09:51 AM · #3
I just covered my work monitor in torn up postit notes. I am STUNNED! That's crazy.
06/19/2007 10:13:22 AM · #4
Originally posted by Greetmir:

You can always use a free utility like pixie to check or Photoshop to determine the RGB values etc ...

I have ColorZilla
installed as an extension on Mozilla Firefox. Gives you a color picker to use on webpages. Web developers would probably like this. The value for both squares is 107,107,107.
06/19/2007 10:14:32 AM · #5
I did what 21.gif bdenny did with the post its. That is AMAZING.
06/19/2007 10:17:58 AM · #6
By far my favorite optical illusion. And it shows exactly why you CANNOT calibrate a monitor "by eye"--you need a hardware device. Your eye is so easily fooled, even by gray (let alone color hues!), that it's impossible to "eyeball" a monitor and get it accurate.
06/19/2007 10:21:23 AM · #7
There are more examples here //web.mit.edu/persci/gaz/
06/19/2007 10:38:31 AM · #8
Jeez, no wonder we need monitor calibration. Damn tricksy eyez.
06/19/2007 10:54:39 AM · #9
Wild...very cool
06/21/2007 10:46:18 PM · #10
Yeah I saw that years ago. I too was stunned the first time I saw it.
06/21/2007 11:01:34 PM · #11
07/22/2007 08:55:58 AM · #12
bump ... because it is worth it ...
07/22/2007 09:46:38 AM · #13
Wow, that is crazy. I have to go find some post-its.

Message edited by author 2007-07-22 09:46:46.
07/22/2007 09:52:52 AM · #14

Just use your fingers to hid some of the surrounding squres and you can see that they are the same!
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