Viewing Tips

The tips below will help you free-view hidden image stereograms, wallpaper stereograms, and stereo photo pairs. No glasses are required to view my stereograms or optical illusions unless noted otherwise. However, these types of images are dependent on stereo vision. Visual impairments to even one eye can decrease your chances of seeing in stereo. For folks unable to see in stereo, I create content like wiggle gifs and optical illusion eye tricks.

If you don’t have a visual impairment, like a lazy eye or blindness, you are likely able to see in stereo vision. Just be patient with yourself when applying the tips below. You’re actually working to relax muscles in your eyes, so this may take practice.

Conventional Viewing

The typical way we look at objects or read is by our lines of sight converging on one point. With this normal viewing there may be a slight turn in of the eyes, and because your lines of sight meet at a single point on the image, it is processed as flat. You won’t experience 3D vision with this method of viewing.

Parallel Viewing

Each eye has a different point of view because of the distance between the eyes. With parallel viewing you want to stretch your focus out past the stereogram you are viewing – like in the Frankfurter Method below. It will make the lines of sight parallel. Note the parallel dotted lines as they pass through the image above, and the lines of sight converge on one point past the image. Sometimes, it is easier to start with the image closer to your face and slowly move it farther away. With my designs, if the lines of sight are parallel, the eyes combine the multiple images into one, creating a sense of depth or revealing a hidden image.

The Frankfurter Method

I’m about to talk about your fingers as if they’re sausages or frankfurters. For real. But this method really does help demonstrate parallel viewing for stereograms. At a comfortable reading distance from your eyes, position your index fingers pointing at each other but not touching. (Like pictured above.) Relax your eyes and focus out past your fingers. A little “sausage” will appear between your two fingers. You can move your fingers closer or farther apart and see the sausage change size.

So now try to do this technique with a stereogram in front of you. You would move your fingers closer to the image while keeping the sausage visible. Your eyes should be relaxed enough to see the 3D image appear in front of you.

Cross-eyed Viewing

My designs are made to be viewed with the parallel viewing method. But many people have an easier time seeing the images using cross-eyed viewing. If you use cross-eyed viewing on my designs, the 3D effect will sometimes pop in instead of out. But you’ll still get to see the fun of the image. For this method you basically cross your eyes with the image in front of you. Your lines of sight will cross and process opposite points of the image.

If you can’t easily cross your eyes, put your finger to the tip of your nose. You can slowly draw your finger to the stereogram, and you should be able to see the stereogram’s effects. Your eye muscles are more contracted with this method and can be a bit of strain. I recommend parallel viewing if you can get it to work.

References:
Sharp, W.L. (1928). The floating-finger illusion. Psychological Review, 35, 171-173.

Wikipedia contributors. Autostereogram. Wikipedia, The Free Encyclopedia. April 17, 2019, 22:25 UTC. Available at: https://en.wikipedia.org/w/index.php?title=Autostereogram&oldid=892945150.