Coolest optical illusion I've ever seen

[rsl12]

Can someone explain to me how this works? I've never seen anything like it.

http://www.patmedia.net/marklevinson..._illusion.html

ps. it seems that it works best if your face is reasonably close to the computer screen (12-20 inches or so).

[ngdawg]

The green you're seeing is the exact opposite of the pink and the strain of your eyes tries to compensate by blocking out the pink...so you see green.

Operating rooms in most hospitals are green to offset the color of blood and thereby reduce the eyestrain of the doctors.

[rsl12]

hm. so you're focusing on the black cross, and your eyes try to block out distracting rotating blinking, so they block out pink? I'm almost willing to buy this...would this work with other colors? does the grey have nothing to do with this? what about the fact that the top pink dots are lighter than the bottom ones?

[Manuel Hong]

wow, that was pretty cool. All the dots disappeared and I saw one green dot going around the +
cool link, thanks!

[rsl12]

actually, i tried stopping the animation and looking at it, and the pink dots still disappear!

[jujueye]

Brilliant! I have always been a fan of stuff like this, but this one is really cool. One of a kind. Thanks for posting the link!

[samson501]

very cool, thanks

[Siege]

Quite interesting, but my eyes keep refocussing once the pink dots leave, causing them reappear almost instantly

[aKula]

Here's a similar one: http://www.michaelbach.de/ot/lum_ade...dow/index.html

Being sceptical I cut out the squares in paint and put them next to each other myself, they are the same!

[Jinn]

Kinda what NG said:

Our eyes have three color receptors, and just like the RGB of a computer, we get all of our colors by combining red, blue, and green. If you've ever seen the "Jesus on the Wall" optical illusion, you'll know that after a certain length of time, your rods and cones start to get "saturated" with a given color. So if you stare a dark (black) image for long enough, then look at a light surface.. you'll see that afterimage for a few seconds while your rods and cones re-adjust. When you stare at the purple dots, they saturate your red and blue sensors. When it gets rid of the purple dot, your cones have to adjust back to the true color, but only your green sensors are still unsaturated. So you see green until it adjusts and combines back in blue and red to get grey. The green "dot" is not actually moving, they're just removing the purple dots in sequence and your rods/cones get to adjust over and over.

The second part where the magenta dissapears completely is our brain saying "WTF?" and getting rid of the random noise. It's called the Troxler effect.. found a decent explanation on the 'net:

"Our brain tends to tune out static stimuli in our peripheral vision (which is why our peripheral vision is so sensitive to movement; it's probably a trait that evolved because it allows us to better respond to threats). That's why you have to fixate on the central point in order for it to work. Turning off the magenta dots in sequence enhances the fading effect, because when the magenta dot is turned off you see dark gray in its place (the same color as the background), which also leaves an afterimage (albeit a fainter one)--in light gray--that partly obscures the magenta dot when it appears again."

[ryfo]

I wear strong glasses and have trouble with most optical illusion puzzles cos my eyes just dont seem to be able to concentrate on any one point , but this one worked! My eyes had trouble readjusting to focussing once I had finished looking at the + though

[analog]

Originally Posted by ngdawg

Operating rooms in most hospitals are green to offset the color of blood and thereby reduce the eyestrain of the doctors.

Green is commonly used in patient and waiting areas, as is blue, for the calming effect of the color on the psychology of those in the environment. Green is typically held to represent nature, health, good luck, renewal, youth, spring, fertility, etc., and is employed in decorating for that purpose. I've never heard anything of the "reduces eye strain from blood" variety. Yellow is not used that much because it makes people think of sickness, which isn't good for a hospital, nor do they use red for what should be several obvious reasons (makes people on edge, easier to anger, makes them think of blood). Black is obviously out, and plain white is just so stark, they usually toss in some blue or green to liven it up a bit.

It's widely used on medical tables and surgical garb partly because it's a light color, but still fairly low in its own luminosity (unless you use some neon green), so it's not distracting or overwhelming when concentrating on other things, but also because of the soothing, calming property it has on those who have to look at it- and in a hospital, every little thing you can do to reduce fatigue and increase the calm is a good thing.

(and I know this first-hand, from my time volunteering in a hospital, i'm not making it up as I go)

[jwoody]

The green you're seeing is the exact opposite of the pink and the strain of your eyes tries to compensate by blocking out the pink

Observe: The Colour Wheel.

[wolf]

That is some cool stuff thanks!

[ngdawg]

Re: Why green is used in operating rooms(to clarify)Linky
Green, which signals nature and renewal, reduces nervous and muscular tensions, and refreshes tired eyes. It is used in operating rooms to counter the color red. It's often seen in libraries because concentration is easiest in a green, gray or blue environment.
Linky
In a paper that was written prior to 1920 entitled "The Green Operating Room at St. Luke's Hospital," Harry M. Sherman, M.D. reports the following research, changes, and conclusions:

Discomfort from glare in operating rooms was caused when the operator looks from the wound to somewhere else and then looks back at the less well illuminated wound - this renders the eyes temporarily useless.

Sherman, advised that the color scheme should start from the red of the blood and tissues, to a complementary color and chose green. Sherman recommended that green, should be used for floor and wainscoting. He selected the green of the spinach leaf - almost the direct opposite on the color spectrum as the red in blood and tissues. Once the floors and wainscoting were addressed he further went on to change the toweling - the draping of the patient/wound area. This was changed from white to green and/or black and then back to green or blue. Scrubs as we know them today were also changed in color.

[analog]

*shrug*

Interesting write-up.

[Redlemon]

Saw this one on a blog today:



If you stand further back, the angry guy and the calm woman switch places. Or, if you can defocus your eyes on command, do that. (This is also why the smile on the Mona Lisa is so mysterious; you can only see it when you aren't looking at it.)

[Cynthetiq]

Originally Posted by ngdawg

Re: Why green is used in operating rooms(to clarify)Linky
Green, which signals nature and renewal, reduces nervous and muscular tensions, and refreshes tired eyes. It is used in operating rooms to counter the color red. It's often seen in libraries because concentration is easiest in a green, gray or blue environment.
Linky
In a paper that was written prior to 1920 entitled "The Green Operating Room at St. Luke's Hospital," Harry M. Sherman, M.D. reports the following research, changes, and conclusions:

Discomfort from glare in operating rooms was caused when the operator looks from the wound to somewhere else and then looks back at the less well illuminated wound - this renders the eyes temporarily useless.

Sherman, advised that the color scheme should start from the red of the blood and tissues, to a complementary color and chose green. Sherman recommended that green, should be used for floor and wainscoting. He selected the green of the spinach leaf - almost the direct opposite on the color spectrum as the red in blood and tissues. Once the floors and wainscoting were addressed he further went on to change the toweling - the draping of the patient/wound area. This was changed from white to green and/or black and then back to green or blue. Scrubs as we know them today were also changed in color.

also the reason why talent sits in the GREEN room before going on air or taking the stage.

[connyosis]

Oh man, the two faces switching places we're really cool. I love optical illusions.

[ngdawg]

I had to take my glasses off for those faces to switch....
one of the simplest eye tricks, index finger tips touching, bring them slowly to your nose and watch them turn into one finger.

[Atropos4]

Really cool illusions. The origional one, It worked at first but I could still see a glow of pink. When I blinked it started over and the it was like the green dot was chasing a pink one.

[TSFM]

As a Psychology major in college, it's stuff like this that led me to make my focus in visio-spacial psychology and the likes. Yum.

[hotzot]

time to take my seizure medicine

[Hanxter]

and by the same token... think pink!!!

[ironman]

Coolest illusion ever, that's for sure, problem is i can't refocuse now!!!

[barenakedladies]

my head a-splode.

[rsl12]

Originally Posted by JinnKai

Kinda what NG said:

When you stare at the purple dots, they saturate your red and blue sensors. When it gets rid of the purple dot, your cones have to adjust back to the true color, but only your green sensors are still unsaturated. So you see green until it adjusts and combines back in blue and red to get grey. The green "dot" is not actually moving, they're just removing the purple dots in sequence and your rods/cones get to adjust over and over.

The second part where the magenta dissapears completely is our brain saying "WTF?" and getting rid of the random noise. It's called the Troxler effect..

Thanks for the explanation JinnKai! It makes sense to me now (or at least, more than it did before). It's interesting that the 'purple' sensors are both saturating and shutting off at the same time, and then unsaturating and turning on because of the movement and change of color.

But why is it that only the pink dots disappear, and not the black text above and below as well? I'm guessing only the color sensors (cones?) are affected, and since the contrast between pink and grey are the same, pink becomes grey when the color shuts off.

[Willravel]

I still think it's witchcraft. But good witchcraft!

[Zeraph]

Wow, those are all really cool. Theyre ones I havnt seen and I thought I had seen most.

[rsl12]

ahhhhh I dugged deeper into Akula's link, and it has the same illusion, only with more fun buttons!

http://www.michaelbach.de/ot/col_lilacChaser/index.html

Here's their explanation (still doesn't explain the magenta disappearing though):

There is something called the “negative retinal afterimage”. It becomes visible when one given hue stays on the same retinal position for several seconds (usually we would move our eyes typically 3 times per second, so this is no disadvantage in normal viewing). The afterimage builds up as that retinal location adapts to this special hue, and when looking at a neutral background the complementary colour is seen.
This is a good thing, normally, because it helps “colour constancy”, that is we see colours somewhat independent of the ambient illumination (compare the bluish glacier noon sun with a reddish tint in the evening living room by the fireside).
Ok, so the afterimage is “burnt in”, that is that retinal location is adapted. Now the magenta patch is suddenly switched to grey. Because of the adaptation, the complementary colour is now seen, which would be green for magenta, or light grey for a dark grey.
The retinal afterimage typically fades away rapidly (over a few seconds under normal conditions). But here this fade-out does not reduce the perception of the afterimage, because a new one is uncovered right after at the next location.
In addition, a Gestalt effect, here the “phi phenomenon” comes into play: the afterimage from the successive retinal locations is integrated and perceived as one single moving object, namely the green disk.
In summary, the following factors make this illusion rather compelling:
it is rather easy to steadily fixate on the centre
most of the time the retinal locations are re-adapted and the afterimage is uncovered only briefly
a Gestalt effect leads to the perception of a flying green disk.

[Gilda]

I wonder if this is the reason why every modern public school classroom I've ever been in has turquoise cabinets, very similar to the default color scheme here, but just a little bluer and just a little lighter.

Or maybe it's just that they all buy from the same supplier.

Cool illusion. I liked the way that the green dot seemed to be eating the pink ones like a pac-man. (I have pac man on the brain lately.)

Gilda

[drewpy]

I still like the optical illusions induced by Rolling Rock better ... This eye focusing stuff is hard work.

[Slyboots]

I saw that one before but I never was able to do it.

I started to get a headache trying to do it just now.

[cj2112]

Originally Posted by Gilda

I wonder if this is the reason why every modern public school classroom I've ever been in has turquoise cabinets, very similar to the default color scheme here, but just a little bluer and just a little lighter.

Or maybe it's just that they all buy from the same supplier.

Cool illusion. I liked the way that the green dot seemed to be eating the pink ones like a pac-man. (I have pac man on the brain lately.)

Gilda

/threadjack
I work for a custom commercial cabinet shop. Our bread and butter is schools. It is likely that the classrooms you noticed this in are either all in the same district or all by the same architect. We do a lot of schools and i find a few colors to be very popular right now, but turquoise doesn't seem to be one of them. However most of the schools we do are in N.Cal.
/end threadjack

[crewsor]

That is really cool. I don't know how it works, but its pretty amazing.

[cellophanedeity]

Originally Posted by ngdawg

I had to take my glasses off for those faces to switch....
one of the simplest eye tricks, index finger tips touching, bring them slowly to your nose and watch them turn into one finger.

Damn my crossed eyes! I can't do these simple optical illusions, nor make the guy switch places. -_-

[politicophile]

Originally Posted by cellophanedeity

Damn my crossed eyes! I can't do these simple optical illusions, nor make the guy switch places. -_-

I had to stand about ten feet from my computer to get the angry man and placid woman to switch places. As for the rotating dot one, you have to be careful not to move your eyes at all or blink, or you'll have to refocus...

Good luck!

[tommyboy]

thats some cool stuff i love things like that

That IS cool! Right up there with that Jesus one......

[Gilda]

Originally Posted by cj2112

/threadjack
I work for a custom commercial cabinet shop. Our bread and butter is schools. It is likely that the classrooms you noticed this in are either all in the same district or all by the same architect. We do a lot of schools and i find a few colors to be very popular right now, but turquoise doesn't seem to be one of them. However most of the schools we do are in N.Cal.
/end threadjack

Three different school districts in three different states. To clarify, the cabinets themselves are gray, the doors are turquoise.

Gilda