link: American Museum of Natural History Public Site link: American Museum Congo Expedition Index Page

Stereographic Gallery

Stereo cameras produce two side-by-side images, one for the right eye and one for the left. Computers display color by mixing varying amounts of three primary colors: red, green, and blue. The information for each color is called a channel. To make an anaglyph, we place the left eye image into the red channel and the right eye image into the green and blue channels. (The lens for the right eye appears blue but it actually is both green and blue.) With the two views now in separate channels, the vertical and horizontal registration of the two images is carefully adjusted. Moving the red channel horizontally relative to the others brings the entire stereo image forward or backward in space.

The AMNH Digital Library Project scanned the original glass plate negatives at high resolution, then called on 3-D imagery expert Gerald Marks to assemble the scans into anaglyph form and prepare them for the web. Anaglyph is one of the oldest ways to display 3-D, yet it has proved to be beautifully suited to the Web and digital multimedia. These glass plate images may have been projected using the anaglyph technique soon after they were returned to the museum almost 100 years ago.

We've selected samples from the approximately 1500 stereoscopic negatives produced by Herbert Lang during his six-year stay in the African Congo. The images presented demonstrate Lang's interest in the daily life and activities of the Congo peoples. These images were also selected for their ability to demonstrate the beauty and utility of the 3-D effect.

For further readings and sites on stereo photography, consult the following links:

Gerald Marks' PullTime 3-D Laboratories

New York Stereoscopic Society

History and background of Stereo Photography from the New York Public Library, by Julia Van Haaften.

National Stereoscopic Association

Stereographs from the California Museum of Photography

International Stereoscopic Union

3D Site

Link to Stereographic Gallery

View the Stereographic Gallery

You can receive a free pair of the red/blue glasses by sending your name, address to: (While you are at it, please tell us what you think of the 3-D site and the Congo Expedition web site in general. We appreciate any and all feedback.)

In order to experience the images presented here in three dimensions one must use a viewing device to provide separate images to each of your eyes. Anaglyph is a technique enable enabling 3-D imagery through the use of simple red/blue glasses. You can receive a free pair of these glasses by writing to us through the email address above.