Do you see 3D?

A cream, orange and yellow exhibit table and backboard, with the title 'Do you see 3D?

Human stereovision is created when the viewpoint from each eyeball is combined by the brain.

How it works

Look at special photos through coloured filters, so the photos appear to be three dimensional (3D). Your brain blends together the image it receives from each eye, and interprets the differences to create stereovision.

Things to try or ask around the exhibit

  • Try swapping the coloured filters between each eye; is there any difference in depth perception?
  • Try closing each eye alternately as you look at the pictures. Do the pictures appear to change 'position'?
  • Why are the pictures printed in two colours?

Background

The pictures may look as though they have been misprinted, but they are anaglyphs. Anaglyphs use two ‘snapshots’ of the same picture from slightly different angles. Each anaglyph picture is printed in different colours (such as one red and one cyan/blue), so when you view an anaglyph through coloured glasses, each eye sees a slightly different picture. Printing the pictures so they overlap mimics the view you have from your left and right eyeballs in your skull.

You can check the difference between each eye’s view by looking at something in front of you and alternately opening and closing each eye. You’ll probably notice that things seem to ‘shift’ in position. This small difference between each eye’s view is called disparity.

Finding the science in your world

Three dimensional illusions including anaglyphs have been used for many decades in books, posters and even movies during the first half of the twenthieth century.