A brain twister

[sizifo]

Here's a pretty cool little braintwister.

http://web.mit.edu/persci/people/adelson/checkershadow_illusion.html

I MAY just be exaggerating here and extrapolating too far, but I think it says something about the subtle impact that tonality has in an image (for lack of a better term). What I mean is: what makes the tonal response of a sensor or of film , or or what makes a particular PP approach appealing or not is a very subtle thing. This little experiment gives a very direct indication of why this is: the mind reinterprets the actual tonal relations using rules best known to itself, so all pixelpeeping bets are off.

 

[jonoslack]

Here's a pretty cool little braintwister.

http://web.mit.edu/persci/people/adelson/checkershadow_illusion.html

I MAY just be exaggerating here and extrapolating too far, but I think it says something about the subtle impact that tonality has in an image (for lack of a better term). What I mean is: what makes the tonal response of a sensor or of film , or or what makes a particular PP approach appealing or not is a very subtle thing. This little experiment gives a very direct indication of why this is: the mind reinterprets the actual tonal relations using rules best known to itself, so all pixelpeeping bets are off.

Excellent - just goes to show why the dynamic range of eyes is so much better than that of cameras!

 

[Jorgen Udvang]

Interesting. I spent five hours on a third class train two days ago, and spent much of the time observing how light fell on the passengers, how it changed and what it was I really saw compared to what I would have captured with the camera.

 

[Jack]

Excellent -- thanks for sharing.

 

[sizifo]

It does get you thinking.

The DR aspect is one thing - but of course there is no obstacle to representing any DR in 2d in principle.

A different point is that, in order to trick the eye into making these (and probably many other) interpretations, the tonality needs to be right. Only a slight deviation and we are, even sometimes subconsciously, no longer happy with it.

 

[Dale Allyn]

Another fun (or funny) way to view the image on the linked page is use a tool such as the Mac OS DigitalColor Meter (a utility included with the Mac OS). Both squares meter at RGB 78,78,78, but of course, appear as though they should not meter the same.

 

[gero]

I can´t believe it or I can´t understand it.

 

[nei1]

All the examples given are in black and white,as they are dealing with variations in contrast.They may be giving clues as to why we find,most of us,black and white imagery so compelling,the image being helped into surreality by confused vibrations in the brain......Fascinating.