Mind Melt

[Loose Canon]

Okay, this blows me away!



Photoshop says it's true!

[pnodrog]

Of all the dirty rotten tricks. I downloaded it to check and even changed it so the lettering was the same to see if that helped - but no it is even more confusing.
Not sure whether to thank you for showing us or never look at one of your posts again.



Time for a drink.

[ANSORB]

Try this. Make a selection of the two squares in Photoshop or whatever. Paste the selected squares on to a new layer and switch off the background layer. Now the squares look and measure the same. The "illusion" that they are different is due to the surrounding context of each square.

When you take a photograph the camera records the actual light values it recieves. You don't, you see and remember more in context, which isn't necessarily the same thing. Hence colour casts, which are just the camera being literal minded about everything and you exercising what you might call a type of visual intelligence, developed over millenia of evolution.

For me, the squares are different, never mind what the colour sampler says.

[SilverYeou]

Haha Omg! That is one BIG proof that something can be different if analyzed in a context, but analyzed them separated from that, and suddenly they are the same. John, your explanation is superb. I believe a good photographer would know that, and take it in consideration when taking a picture. Many times it is not what he/she sees, it is what the camera+lenses+filters+camera set up see.
This post has shown even more of why what we see is sometimes much different than what the photo shows.
I thank you for the post, Terry! (but you are paying my headache pill hehe)

[Loose Canon]

Of all the dirty rotten tricks. I downloaded it to check and even changed it so the lettering was the same to see if that helped - but no it is even more confusing.
Not sure whether to thank you for showing us or never look at one of your posts again.


Time for a drink.

This is a lowdown dirty rotten trick L. Paul!

I’d go with never looking at one of my posts again!

I even sampled the two squares to a fresh layer (aside from taking color values by number) in Photoshop (clone sample), and sure enough… the same!

I think the lesson here is never trust Photoshop!

Though I know them to be the same, I still can’t see it with my own eyes!

Have one of those drinks for me would you please? I'm getting Lu's headache!

And just send me the bill Lu! I guess I have it coming!

[davidedric]

Now clone out the green cylinder, and what do you see?

[Loose Canon]

I tried cropping out the green cylinder. No change for me.

Aside from the checkerboard, it also has to do with the shadow the green cylinder is producing!

[revi]

The shadow is the whole point of that image, to show that your brain is interpreting the image (could have been a dirty spot as well), and
'sees' a colour (intensity here) based in part on its context (or surroundings if you like).
And isn't that effect what we use when applying local contrast enhancements?

Another nice one with colours is http://michaelbach.de/ot/col_Munker/index.html

[davidedric]

Yes, I know. I was just fantasising about some kind of edit that would remove an object and its effects. Sorry, I was just being silly

[yauman]

Here's a room size model of this with video to show how the shadow changes our perception:
http://www.youtube.com/watch?v=z9Sen1HTu5o

[benm]

This is a terrific optical illusion. I played around with it to try and figure out why it is so good. A big part of the effect is that the letter A is light colored and the letter B is dark. Good one!

[pnodrog]

This is a terrific optical illusion. I played around with it to try and figure out why it is so good. A big part of the effect is that the letter A is light colored and the letter B is dark. Good one!

Yes I saw that but changed the letters so they were the same tone and it was just as confusing. Have a look at the second version above.

[rpcrowe]

The Canadian Film Board produced a wonderful film in the 1960's which concerned itselt will visual illusions. I don't remember the name but it was done by the Moody Institute. It was wonderful and showed how our vision can deceive us in seeing colors, sizes and relationships between subjects...