[tig] This is very grey to me...

jeffh jeffh
Thu Apr 22 17:58:06 BST 2004


Some of you may have seen this before, or other things
like it; I just found this yesterday.  Look at box A, and 
then box B.  They look like they are different shades
but in fact they are not - they are identical.  If you believe 
me, proceed to paragraph 2.  If you do not believe me, 
save the pic, and open it up in a paint program.  Select 
and move a part of A into B, or vice-versa.  See?  
Alternately, hold your color dropper tool over box A and 
see what color is displayed (Jasc?s Paint Sho Pro has 
this; I am sure other programs do as well, tho I am not 
sure if the ?dropper? would be called something else).  
See what RGB value is displayed; I get 107 107 107.  
Then hold the tool over box B (try to keep away from the 
edges) ? the same 107 107 107, right?

So, my question is: why?  Why do both boxes appear 
different when they are in fact the same?  What is making 
my brain perceive the boxes as different ? and better yet: 
how do I get my brain to stop doing that!?!??  <cough>  
It is not the prescence of the letters ?A? and ?B? ? if I crop 
each box, and paste both into a new image, they now look 
the same, thus proving that the letters are not causing the 
boxes to appear different in the original image. Nor is it the 
prescence of the cylinder ? removing it, or altering it?s color 
does not change anything.  Therefore, I am figuring it is not 
the boxes themselves, but the SURROUNDING boxes ? but 
what gives?  Why would the shade of any of the surrounding 
boxes affect how others are perceived?

And from that, comes two questions:

1.  If the board were oriented differently, would this affect how 
the brain perceives the boxes?

2.  How about looking at the same box in real life as opposed 
to on a computer screen ? would that make any difference?

Anyone who can properly explain this will be owed a night of 
heavy drinking

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