Producing an Anaglyph
...in Photoshop or any other image editing package that gives you access to the RGB channels for an image; Basic steps as follows:
- open the two RGB images for editing, identify the LHS view and the RHS view.
- because your typical anaglyphic glasses are red (LH lens) and blue/green (RH lens), the overlaid image you are going to produce will provide a LH eye image from the red channel of the LHS view, and a RH image from the blue/green channels of the RHS view.
- go to image>adjustment>levels and perform colour channel adjustments, i.e. for LHS view, make green and blue output levels 0; for RHS view, make red output level 0.
- Finally, the foremost image will also need opacity set to 50% so that you can see the background image through the foreground.
- Now nudge either image about the canvas while you are wearing the anaglyphic glasses. focus on a key central part of the image (this has implications for your method or approach at photographic composition, i.e. centrality/peripheral and how you achieve the impression of depth - not just the scientific construction of depth using the RGB image edit).
- for an interesting variation, I could adjust the channel filtering to another complementary colour set, i.e. purple-orange, or other. To do this I expect you'd need to provide suitable lenses for the viewing classes and to calculate the correct complementary RGB subtraction for each image to filter down to purple or orange spectrum. An experiment for another day.
An alternative to the Anaglyph is Stereoscopic imagery
Another method of producing a 3D image is equivalent to the old method of 3D photography that placed two (small) images side by side in a viewing frame. The pictures were viewed through binocular lenses which are aligned such that the image is brought into focus proximally (near) while the eyes themselves are directed distally (distant). The same effect can be achieved by practice without the lens apparatus; usually by directing your gaze behind the image while attempting to bring the image into focus (without looking at it as such). This approach requires the viewer to cross eyes until the two pictures overlap, then bring the images themselves into focus, again without directing your eyes to the plane they present in as such.
For more information see pages like Geowall for useful tips on using photoshop and other tools to prepare anaglyphs and stereographs from photographs.