Is this true?

[Shell Beau]

Tiles A and B are the same color.



Squares A and B are the same color, you have to open up a paint image and put the tiles side by side.
I'm not computer savy, so I wanted someone to test it out.

[northzax]

1. fish

[Shell Beau]

2. Sorry, I forgot to add what to do.

[Blue-Jay]

3. chips

[teach1st]

4. It's true N/T

[Shell Beau]

5. Did you test it out? I don't know how. I want to see them side by side.

[teach1st]

6. Side by side (well, overlapped)

[Shell Beau]

10. Thanks. That is screwy!

[kick-ass-bob]

7. I tested it. They are the same.

However, even now, I still don't believe it.

[Shell Beau]

8. Me either. I trust my eyes (well, most of the time)!

[teach1st]

15. I haven't trusted my eyes since the late '60s N/T

[salvorhardin]

9. It's true

I just roughly selected the 'B' square and moved it alongside the 'A' square. I added the drop shadow for no real reason.

You could also test it out with a color picker tool like this one: http://www.datastic.com/tools/colorcop

[hyphenate]

11. According to "eyedropper"

which reads the pixel colors, they are both the same, coming out at a hex value of R 107, G 107 and B 107--both of them. How about that!

[Midlodemocrat]

12. It's true. I just tested it.

But, I still can't figure out HOW it is true.

[aeolian]

20. It's your brain.

You know that tile A is dark colored, but well-lit; and you know that tile B is light-colored, but in shadow.

On the computer screen they both have a grey value of 107 (0 is black, 255 is white). But your brain helps out, and you perceive the light and dark tiles in their proper checkboard pattern.

Thank evolution that we evolved from binocular tree-dwellers with some predatory tendancies. :)

[Midlodemocrat]

23. Ahh, ,but you are assuming I actually HAVE a brain.

Big assumption on your part. Ha. Ha.

[LynzM]

13. They are

If you copy the image, paste into paint, select half and move it 'up', you get:

[Spacemom]

14. Weird

I had to test it for myself, but it's true.

It's way too early for mind-benders like this.

[teach1st]

16. I think the explanation is that...

...our minds don't interpret absolute color values, but, instead, comparative color values. (Just a guess)

[Shell Beau]

17. Sounds good to me!

:shrug:

[aeolian]

22. Yep.

And more succinctly stated than what I said.

:toast:

[salvorhardin]

18. The explanation for it is here

Why does the illusion work?

The visual system needs to determine the color of objects in the world. In this case the problem is to determine the gray shade of the checks on the floor. Just measuring the light coming from a surface (the luminance) is not enough: a cast shadow will dim a surface, so that a white surface in shadow may be reflecting less light than a black surface in full light. The visual system uses several tricks to determine where the shadows are and how to compensate for them, in order to determine the shade of gray "paint" that belongs to the surface.

The first trick is based on local contrast. In shadow or not, a check that is lighter than its neighboring checks is probably lighter than average, and vice versa. In the figure, the light check in shadow is surrounded by darker checks. Thus, even though the check is physically dark, it is light when compared to its neighbors. The dark checks outside the shadow, conversely, are surrounded by lighter checks, so they look dark by comparison.

A second trick is based on the fact that shadows often have soft edges, while paint boundaries (like the checks) often have sharp edges. The visual system tends to ignore gradual changes in light level, so that it can determine the color of the surfaces without being misled by shadows. In this figure, the shadow looks like a shadow, both because it is fuzzy and because the shadow casting object is visible.

The "paintness" of the checks is aided by the form of the "X-junctions" formed by 4 abutting checks. This type of junction is usually a signal that all the edges should be interpreted as changes in surface color rather than in terms of shadows or lighting.

As with many so-called illusions, this effect really demonstrates the success rather than the failure of the visual system. The visual system is not very good at being a physical light meter, but that is not its purpose. The important task is to break the image information down into meaningful components, and thereby perceive the nature of the objects in view.

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

[Shell Beau]

19. Oh okay!

That really makes no sense to me, but it sounds scientific.

[salvorhardin]

21. If you ever get a chance

or you're bored... :-)

Read up sometime on all the visual processing that occurs inside your eyes before the signals get transmitted to your brain for even further processing. It's fascinating stuff and really underscores how very little of what we think we see is actually what we saw.