Amazing optical illusion makes black and white image appear color

@SamSam I appear to have strong inter-occular transfer. I wonder if that’s bad or good?


So what you’re saying is that Trump is really purple, but people keep turning away after staring at him, and only ever see the after-image?


It’s more than just a cone fatigue effect (though that is key to how it works.)
For evolutionary reasons the human optical path is quite badly designed. Although the cones are red, green and blue-green sensitive, the actual output to the brain is encoded as blue/-yellow and red/-green. (This explains why we cannot, in fact, see certain color combinations correctly).
The castle picture has very strong red and blue components. This means that the channels to the brain tend to revert with time towards zero. The flip to black and white thus causes a very strong stimulus of the yellow and green signals, which is why the effect is so strong. But because it is a pulse signal, the illusion is relatively short lived, rather than a slowly fading after image.

@MarkGisleson - Most psychological illusions are caused by time-dependent effects on the nervous system. You can’t understand them by trying to reduce them to atoms.

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| For evolutionary reasons the human optical path is quite badly designed.

Stop sitting on the fence.

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Did you watch the gif?

Is it not one? Or you do not see one?

You hadn’t mentioned that. You were insisting everyone else was incorrect.

Ever talked to someone with a hearing aid who tells you you need to speak louder, when that need is not actually yours?


Most illusions do not involve animated GIFs that set up your eyes to fail. The description failed to make it clear that this is not a classic optical illusion, but is simply an animated trick to tire out your eyes (and no, it doesn’t work for me).

Sorry, this is way too gimmicky to be impressive. Did you know that if you stare at the sun you’ll see a Huge White Spot for a while afterwards? Wow! Is that an optical illusion? Or just optical abuse?

Escher drew optical illusions. This is an optical overload. Not the same thing.

MY eyes were not set up to fail.

Are you disappointed in BoingBoing?

Why would I be? I’m just disappointed that so many people took time to correct me. I have now done my homework and realize there are three kinds of optical illusions. This is a variety that relies less on art and more on manipulation. I assure you, I will never question anything on Boing Boing again.


An optical illusion (also called a visual illusion) is characterized by visually perceived images that differ from objective reality. The information gathered by the eye is processed in the brain to give a perception
that does not tally with a physical measurement of the stimulus source.
There are three main types: literal optical illusions that create
images that are different from the objects that make them, physiological
** illusions that are the effects of excessive stimulation of a specific **
type (brightness, colour, size, position, tilt, movement), and cognitive illusions, the result of unconscious inferences. Pathological visual illusions arise from a pathological exaggeration in physiological visual perception mechanisms causing the aforementioned types of illusions.

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I wonder how everyone feels about the time you took to incorrect the post?

and all these details about how not incorrect you were technically.

I will care as much as you do. Lead with wisdom. Our egos have the same value as yours, please and thank you.


“Subjectivity is a central philosophical concept, related to consciousness, agency, personhood, reality, and truth,”


#those are not questions.

Had you questioned it… well… we will never know.

depends where it is shining from. “Wow!”


Who is the master who makes the grass green?

The grass is only green in English.

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Then you haven’t seen my lawn!


Why, is it verde? Viride? žalias? зеленый? 绿色?
Or just plain brown?

I will assume it isn’t in England, then.

Reminds me of the laryngeal nerve of the giraffe.

Or rabbits eating their own poop because the bacteria that can digest their food are stored in a chamber after their intestinal tract.

Not necessarily. I didn’t even know there was a dot to look at the first time around and it still worked.

Yeah, pretty obvious that’s what’s happening… Colour me impressed but not amazed.

Did you know that if you stare at the sun you’ll see a Huge White Spot for a while afterwards?

Stare at the sun for more than a split second and that will be the last thing you see for the rest of your life. You will be blind.
BTW if you inadvertently happen to glance at the sun you will see a big BLACK SPOT not white.