Anaglyph Glasses

The classic "anaglyph", or "filtered-viewing" method requires the viewer to wear red and cyan  "anaglyph-glasses".  Red light enters the left eye only (in principle), while blue-green light enters the right eye.  Anaglyphs are made by combining color channels from the left and right images of a stereo pair into a single color picture.  For example, a monochrome composite can be constructed by taking a B&W left image and overwriting it into the red channel of the right image's B&W frame.  The resulting right frame is then called a "Gray Anaglyph".  

Surprisingly, in spite of the color-filtering properties of the anaglyph glasses, pretty decent pseudo-color stereos can be constructed by mixing the left and right color channels to produce a color composite called a "Color Anaglyph."  Some scenes work better than others. For example, a picture dominated by stark reds or deep blues is difficult to convert into a good color anaglyph.  There is often a trade off between color accuracy and comfortable 3D rendering.  A good color anaglyph should not suffer red-blue ghosts and retinal rivalry (where the color separations are so big the brain has trouble fusing the two images).  It will also have reasonably decent color.  Greenish scenes are easier to make into good color anaglyphs.  Anaglyphs can be improved by violating certain stereo window principles.

The anaglyphs on this site are computer generated by the server, using various anaglyph (i.e. channel mixing) algorithms.  Human-intervention could probably improve some (perhaps many) of these anaglyphs by adjusting the mixing parameters and the stereo window.  But because of the high number of images, and the superiority of many of the other viewing methods, the "by- hand" approach has not been used on this site.

Color Anaglyph of Avalanche Creek	Gray Anaglyph of Avalanche Creek