In the 1950s, a number of movies were shown at the cinema in 3D. Through wearing specially tinted goggles, an illusion was produced where a 2D image was made to look like it had depth. Make your own 3D pictures with this activity.
WARNING: This activity involves downloading software for the internet. We've tested the software and know it is safe, but be very careful to check both the credentials of the software maker and who is asking you to download it when downloading anything from the internet.
You will need
Digital camera
Computer with MS Windows operating system (preferably XP)
Take one piece of card and measure the halfway mark on the long edge. Draw an arch 2cm high and 2cm wide at this point and cut it out. This will be for your nose.
Put the card against your face with the arch on the bridge of your nose. Using a pencil, carefully and gently mark where each eye is. Do not poke the pencil through the card.
Around each mark, draw a box 2 cm high and 4cm long for eye holes. Cut them out neatly and hold the card up to your face again. Make the holes a little larger if you have trouble seeing through them.
Use this as a template for the second piece of card. Draw around it and cut the second card into the same shape as the first.
Cut a square 5cm high and 6cm long from the red and the blue cellophane. Use sections that are not creased or wrinkled, if you can.
Smear glue over the backs of each card. On one card, place the red square over one eye and the blue square over the other, and squeeze the other card on top, trapping the cellophane in between.
Making the images
Download Callipygian 3D for free from their website. It is an executable 336 KB file. The file is freeware and requires Windows (preferably XP) to run.
Set up the scene you want to photograph in 3D. It might be easier to practice on something simple at first, like a small object on a table.
Take two photos of the scene – the second photo should be taken about 5cm to the left or right of the first if it is close up. Download these onto your computer.
Open Callipygian. There will be a left and a right panel in the program window. Drag the picture taken on the left to the left box, and the other picture to the right box.
Use the mouse to draw a box on the left picture over the area you want to be 3D.
Click 'View 3D Anaglyph' under 'Preview 3D' in the main menu. The window that comes up will have a blurred red/blue picture in the middle, a slider on the right and another down the bottom. Put on you glasses and look at the picture. Adjust each slider until the image looks 3D.
Save your project. You now have a 3D picture!
What's happening?
To understand what a 'dimension' is, think of a box drawn on a sheet of graph paper. Its height (Y axis) is one dimension, and its length (X axis) is a second dimension. It is 2D. But if it's a box (a cube), it also needs width – a third dimension – which needs to come out of the paper at right angles to the page.
Humans have pretty good binocular (meaning 'two eyes') vision. Each eye sees mostly the same thing, just from two slightly different angles. The contrast between each image allows us to judge the depth of an object. Otherwise we'd have to rely on other clues, such as size, to know how close something is.
In these 3D pictures, each eye is being tricked into seeing a different picture to the other eye through the use of colour filters. The picture itself is actually two pictures in two different colours on top of one another. One eye has the red picture filtered out, so it only sees the blue. The other eye sees the opposite. Since each picture is in a slightly different position, the brain has to put the information together in the same way it would if it was seeing a real 3D image.
Applications
Three-dimensional pictures are certainly more life-like than just two. If you've ever been to see a 3D movie, you'll know they can be quite an experience. In the past, a number of strategies have been used to create 3D images from 2D pictures. One is the 'stereoscope', which relied on special glasses that held two different pictures in a way that each eye could see only one of them. Today, special polarised glasses are used instead of coloured filters. They work in the same way, only with polarised light instead of colour, which gives a much more vivid and lifelike picture.
The problem, however, is we need to wear the glasses in the first place. One day it might be possible to watch 3D television without anything but your own two eyes.
