A stereoscopic image is usually presented as a stereoscopic pair of images. Here’s a typical historical stereograph in the public domain:
Stereoscopy was once quite popular, and there are many thousands of historical stereographs available. While there are only a few dedicated 3D cameras available today, enthusiasts have continued to create stereographs.
Where to find stereographs
You’ll find many free modern stereographs in Facebook groups, Reddit groups, in museum collections, or on dedicated websites. Here are a few links to get you started:
- London Stereoscopic Company
- The Getty Museum (over 20,000 historic public domain images)
- The New York Public Library Digital Collection (over 42,000 historic public domain images)
- Stereo Photography 3D Photo Fan Club
- National Stereoscopic Association
- Stereoscopic 3D AI Art & Stereoscopic 3D Fractals
- Magic Window X3D
Options for viewing stereographs
You can view stereoscopic content in many ways. For the best quality, you can use a VR/XR device like the Apple Vision Pro, or the Meta Quest, and a custom app. Some TVs, computer monitors and projectors allow 3D content to be shown to viewers wearing special active or passive glasses, and glasses-free display devices also exist.
Many historical stereographs (stereo photographs) were designed to be placed in a stereoscope, a device that presents each of the two images to the correct eye. Today, you can place a mobile phone in a dedicated viewing device, to do the same job. Some modern stereographic viewing devices are available from The London Stereoscopic Company. As you’ll have to use the device’s screen to load each image, the process can be a little cumbersome, but the images should look good.
If you don’t have such a device, or would prefer not to use one, it’s still possible to view color digital stereographs on a standard 2D screen — but you’ll have to learn to control the positioning of your eyes to create a stereo effect. Some people find this easier with a standard “parallel” Left-Right layout, while others prefer a “cross-eye” Right-Left layout.
To make it work, you’ll need to learn to defocus your eyes slightly (to see parallel images in 3D) or cross your eyes (to see cross-eye images in 3D). Some people can use either technique, while others can only use one. Sadly, not all images are made available in both formats. If you’d like to try this yourself, here’s an illustrated WikiHow primer called How to View Stereograms, and here’s another guide from The Stereoscopy Blog.
Finally, Red-Cyan glasses can be used to view images in “anaglyph” format. While these glasses are inexpensive, most color information is lost, and it’s not usually the preferred option.
A free solution for the Apple Vision Pro
If you have an Apple Vision Pro, I have created a free app called Stereoscope to help you view stereographs presented in parallel or cross-eye formats, without having to defocus or cross your eyes, and with the freedom to bring the 3D image closer to you so you can see it in more detail. As the Apple Vision platform becomes more accessible over the next few years, I hope this app opens up stereographs to a wider audience.
