## Stop Trusting Everything You See

### Background

Everyone who comes on this blog often knows that I’m a huge fan of Prof. Rischard Wiseman. If you don’t know that, well, I urge you to check out every other post where I’ve mentioned him (Yes, he’s the same man who makes videos for the YouTube channel 59 seconds). The man certainly knows how to play with your brain. And once again he has blown my mind with this amazing optical illusion that he shared on his blog.

This is probably the best optical illusion I have ever seen. That is because, it’s somewhat like the Mc Gurk effect (do check it out too) – in a way that, it is one of those illusion where even after you learn about it, you still can’t see through it. I mean, it will continue to fool your brains, even when you know the trick. It’s an eternal magic trick. Enough of the build up. Now, let’s see what this illusion really is…

### Wash your eyes if you have to

In the image below, you’ll see a pinkish swirling image and inside it you’ll see that there are green swirls and blue swirls embedded. What if I tell you the green and the blue you see are the same colors? Just because I’ve written something that’s completely opposite to what you see with your own eyes, you’ll probably laugh on my face and call me mad. I did that. I trusted my eyes more than any one else’s word. So I had to verify it…

### The Proof

Ok, if you take my word for it, fine. If you don’t believe me, you could use a simple image editor, pick colours and check. Both the colours you see here, green and blue, have the same hexadecimal value: #00ff96.

Another thing you could do is, download the image, zoom it to a great extent, such that both the colours that you see are in the same frame and you’ll see that the colours are actually same. Here’s a picture of that zoomed part…

Here’s an image I created where we have the #00ff96 coloured square overlapping the seemingly blue and green parts. If you, cover everything except the topmost corner first, look at it carefully, and compare it with the bottom-most corner, you’ll see that the colour of the square block perfectly matches that of both the “blue” colour and the “green” colour in both areas. And it is the same block.

The several other blocks in the middle are for you to remain sure that the colour of the block doesn’t change in between.

There’s another image in which it works…
Even here the blue and green colours are actually the same colours…

## There Is No Pink

###### By Anupum Pant

As we’ve seen before in a talk by David Eagleman, that there is nothing like colors really. They are simply electromagnetic waves with varying wavelengths. Colors are perceptions created by our brains that give us an evolutionary advantage to differentiate things easily. Without colors it would have been really difficult for us to spot fruits on trees. Of course that is just one of the millions of examples of how colors help us.

Perception kept aside for a while, we actually do know that there is a spectrum of visible light as we see it – ranges from violet to red. We see this spectrum on rainbows and thin films. Each of these colors on the spectrum is a wave (and particle) that has a particular frequency.
Mysteriously, the universal symbol of love, the color pink, is absent in this spectrum. There is no specific frequency for the color pink. There is no pink. Still we see it. So, what is pink, really? If it isn’t in the spectrum, why do we see it?

### Why do we see pink?

Single type cone alone: We detect colors through these things called cones that are present at the back of our eye. There are 3 types of cones – let us call them red, blue and green. So, if an object absorbs all the white (sun) light and sends just the red color [waves] towards your eyes, red cones get activated and your brain tells you, you are seeing the color red. Similarly, green or blue cones get activated when the respective green or blue waves come towards your eye and then you are able to see the colors green or blue.

2 of them together: For other colors, things can get a bit complicated. To see pure yellow, both red and green cones have to get activated. Similarly, when green plus blue cones get activated, you see cyan, and blue plus red cones let you see the color magenta.

But cone aren’t switches that go either one or zero. They are like sliders. For instance, to see the violet color, your blue cones get fully active, while the red cones are activated only to a certain extent. As a result, your brain says, violet! That is 2 types of cones working together.

3 of them together: Now let us see how three of them work together. The color white activates all the 3 type of cones fully. Black activates none. And so on…

Pink does something similar as it uses three types of cones. To see pink, all three types of cones have to work together.  When red cones get fully active and the other two are only partially activated, we see the color pink.

So, even if objects don’t reflect magenta, yellow or pink (or several other RGB combinations like that), our cones can send mixed signals to our brains and the brain in turn creates these colors for us. In reality, they don’t exist.