Making a Full-Colour 3D Anaglyph

(Link to Assignment is at the bottom – please read all of this first)

The ability of our eyes and brains to see in three dimensions is due to depth perception. Depth perception comes from many cues, such as diminishing size and light value as distance increases. But the most important cue for humans comes from the fact that our left and right eyes look at the same scene from slightly different angles. Our brains integrate the two images into one seemingly 3D image.

If you’re not sure about this, try closing one eye and walking around a room. You’ll likely find it a bit harder to judge how far away objects are.

There are many schemes to mimic what our eyes do, none of them as good as the real thing! They usually involve taking “stereo pairs” of pictures from slightly different angles. But how do you combine them onto one print or screen and still retain the depth info from both images?

Our technique starts by removing all but the blue hues from one image and the all but the reds from the other. They’re then combined in a way that looks confusing and shadowy to the normal eye. But when a red filter is placed over one eye (the right) and a blue filter over the other, suddenly our brains see two images through each eye separately, and integrate them into a 3D whole. It’s not perfect, but it’s an interesting medium to explore.

Steps

1. Compose your photo carefully, considering the following:

• As always, use your artistic eye to create an engaging image
• Make sure it has lots of depth – clearly defined edges that move toward and away from the camera
• Go for maximum depth of field, so really close objects are in focus as well as further ones
• Focus to about the middle of the closest and furthest part of your subject
• Whites, light browns, yellows and grays work better than blues and reds
• Shoot the first image, and carefully move to the right, not very far, about 10 cm for close-ups, just enough to change the point of view as your 2 eyes would see it. Once you get good at it, experiment with different separations.
• Make sure you focus on the same spot for the 2^nd image, and maintain the same height, angle etc. A tripod really helps!

2. Now, open the 2 images in PhotoShop. Use the Window, Arrange menu to tile them vertically (side by side), right eye image on the right. Confirm that the left and right are what you’d see from your two eyes – same scene, but just shifted slightly.

3. Click on the RIGHT image. Select all (Ctrl-A), and Copy (Ctrl-C)

4. Select File, New, and click OK. This gives you a blank document the same size as the pic you just copied.

5. Open the Channels menu (Window, Channels). Click on the Red channel. Paste (Ctrl-V). This should put the Right image on the screen, in Black and White.

5. Go back to the LEFT image. Select all (Ctrl-A) and Copy (Ctrl-C).

6. Now go back to your new document, and select BOTH the Green and Blue Channels (click on Green, then SHIFT-click on Blue). Paste (Ctrl-V) which should show the left image in a blue-green shade.

6. Click on the RGB channel Eyeball to show the preliminary Red-blue image. Likely the two images will be out of alignment, as shown below, where the ears don’t line up:

7. To align, you need to show all channels (eyeballs), but select only the Red channel (click on the word Red, as shown above).

8. Now select the Move Tool, and make sure “Show Transform Controls” is checked. Pick a spot on your subject about mid-way in depth, like the horse’s ear. Slide the red channel image around until it lines up (at the chosen spot) with the blue image. Other parts of your image at different depths will remain unaligned – that’s what will give depth.

9. That’s about it! - try it out! Put your trendy 3D glasses on, RED on the RIGHT eye. If you move your whole head left to right (MOVE sideways, not rotate), you should see your object in 3D. You can continue to shift the red layer with the glasses on, until you achieve the optimum feeling of depth without much distortion.

That’s it! Save in both PhotoShop and JPEG format

Assignment & Evaluation (Due May 7)

More Examples