Amazing Optical Trick & How It Works


I came across this post on Facebook and found it really interesting. Try it out yourself and see what it does:

1. Stare at the red dot on the nose for 30 seconds
2. Turn your eyes towards the wall/roof or somewhere else on a plain surface.
3. Keep blinking your eyes quickly and continuously.
(After blinking about 3-4 times, close one eye and you will see the image moving across the wall.)


Most people tend to believe that there is something magical about this particular image. So I made the trick again with my own image:


How It Works

It seems tricky at first but its really a pretty simple concept. First, lets see what this image is made of. It is a negative image with 3 dots – Red, Green & Blue located at the center(approximately) of the face. As we know, RGB are the 3 primary colors which can be used to create all other colors. But what exactly is a negative image? It is just a total inversion of the original image. While using image editing software, you may have noticed the option “Invert Colors” which does the same thing as “Convert image to negative”.

When we invert colors, we are referring to an inversion in which light areas appear dark and the dark appears light. This inversion is called a negative image. Further, a colored negative image is color reversed i.e. each color is replaced by its complimentary color in the color model – red is replaced with cyan, green with magenta & blue with yellow.

So, when we look at the negative image, we are looking at the complimentary colors of the original image. Also, if we invert an inverted image i.e. take the negative of a negative image – or compliment the colors of a negative image – we get back the positive/original image. That is exactly what we do in the above trick. The only difference is we use a certain property of our brain instead of a software.


The compliment of the compliment gives us back the original image


When we stare at the red dot, the photo-receptors corresponding to red color in the retina are exhausted, lessening their ability to send the information to the brain. When we look at the wall or roof, the red portions of light incident upon the eye are not transmitted as efficiently and we instead get the illusion of viewing the complementary color of red. (which is really the color in the original image).

Adding Green & Blue dots on the image make the brain compliment all the colors of the image and thus form the positive image on a plain surface. And hence, you get the original image formed on the wall!

The latest one (October 2013):



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