The Third Dimension

Put on your red and blue glasses and take a look at the picture below.

Courtesy of flickr user: shared via CC BY 2.0

How does it look? The picture should ‘pop’ out at you, with some bits of cactus looking closer to you than others. The picture is flat, or 2D, but it has the illusion of having depth, or being 3D.

How does it work?

Hold one finger up just infront of your nose. Close one eye at a time. Your two eyes don’t see the same image. Because your finger is so close to your nose it will jump around depending on which eye is open. Each eye sees something a little different.

Now with both eyes open, try to focus on your finger. Your eyes have to focus very close together to focus on your finger. This tells your brain that your finger is close to you.

For flat pictures to look 3D they also have to give each eye a different picture.

Let’s look at a simpler picture to investigate this further.

Put your glasses on and look at this picture of Meg and Pico. The blue lens stops one eye from seeing the blue line and the red lens stops the other eye from seeing the red line. So each eye sees a slightly different, black drawing. Your eyes focus a little in front of the screen to make the two pictures overlap into one. This tricks your brain into thinking that the picture is closer to you than it really is.

Now look at this picture, without your glasses on. Can you see how it is different to the one above?

Meg is the same in both pictures but Pico is different. Pico’s red and blue lines are even further apart in the second picture. This means your eyes will have to focus closer to put the two images together, which means it will look like Pico is closer to you than Meg is. Put the glasses on and see if we were right.


We’ve rounded up some cool 3D pictures for you. Take a look at them with your glasses on and try moving your head around a little. If you want to find more 3D pictures you should search for the word anaglyph.

The Sun

Image credit: Courtesty NASA | Source=


Image credit: Courtesy NASA/JPL-Caltech

Video and Animation

The 3D effect also works for videos and animation. Put your glasses on and enjoy.