Anaglyph (3D) Imaging and Field Geology

This website is a result of a 3D geology-visualization study. All images are anaglyphs that require red-and-cyan viewing glasses and were created using digital cameras and image-enhancement software.

The selection of images and localities within this website reflect two criteria: 1) places the photographers chose to go during volunteer outings, and 2) selection of images that actually worked in anaglyphic (stereoscopic) presentation. A perusal of this website shows a wide range in stereographic successes and short-comings. A mix is presented to illustrate how anaglyphic imaging might be used.

Hopefully, with time, more imagery will be added to provide more comprehensive coverage of national parks and the San Francisco Bay region's geology and natural history. With experience, luck, and good weather, more representative images of various localities and geologic features will be added.

This mobile stereo camera setup consists of two CD Mavica cameras, a light-weight graphite camera tripod with carrying strap, various bolts and washers, and a cross bar made from a cut segment of galvanized angle-iron bar (available at most hardware stores). Not shown is a battery recharging system that can be plugged into a vehicle's power supply.

The CD Mavica cameras have the advantage of a 6X zoom, a plethora of setting options (flash, shutter speed, timer, focal settings, etc.), and the ability to record about of 180 megabytes of images onto mini CD-ROMs for archiving (with up to 4 megapixal images). However, two smaller cameras would be better for close-up action stereographic photography.

The variability in spacing along the bar is an important feature that allows for both close-up and long-distance stereoscopic images. It is important to keep the cameras parallel (in most cases). The closer the object, the closer you want the cameras. It is best for beginners to experiment with different settings, but keep notes for each test.

Although stereographic images can be made using a single camera, two cameras on a tripod base are essential to ensure consistent parallel camera orientation and to capture action (like waves, crowds, animals, etc). We found it best to reset the camera image number on both cameras to "0" at the beginning of each photography outing. From the start, batteries should be recharged, disk space cleared, both cameras should should be reset for standard bright, outdoor settings, and the maximum megapixal setting should be used. On a typical weekend outing is was not uncommon to take over 100 images per day (per camera). Only a small percentage of these images were typically used.

After a stereo pair of images have been acquired, the construction of a "successful" anaglyphic image requires image enhancement software and an appropriate computer. Many computer graphics programs are available that can convert images to anaglyphs, however other image enhancement effect are needed for best results (such as resize, transform, brightness-contrast, color management, etc.). All images on this website were made using Adobe Photoshop (7.0) on a standard PC (with Windows XP). It is important to keep track of "left" versus "right" images. We advise setting up a directories using a specific place names, and then having subdirectories labeled "left" and "right" for the appropriate images. With practice, the numbers in both directories will be the same. Save the completed anaglyphs in the parent directory. Be sure to keep a back-up directory of all your original images.

Below is an example of how an anaglyph is constructed. The bison below was grazing in a pen in Golden Gate Park in San Francisco. To fit on this web page, the images were cropped from their original full-size image. All anaglyph images are processed with RGB levels (red-green-blue) and saved as single-layer ".jpg" graphics. We also chose a resize image standard of 800 pixels wide; height varies with constant proportions for each images.

Select and copy the red image and paste it as a new layer on top of the cyan image. You must make the red layer transparent so the cyan image is visible. In Photoshop, this can be done on the "Layers" window by changing the bar setting from "Normal" to "Screen." It can also be done by changing the opacity of the top red layer from "100%" to "50%." Once the image is transparent, you can move, transform, readjust levels, contrast, or other settings to make to most visually pleasing anaglyph (using red-and-cyan glasses).

When the image is ready, choose "Flatten Image" under the "Layers" menu and then "Save As" a .jpg image with a new name.

With practice, generating anaglyphic images can be a fast process. Be aware it typically takes more time to process the images as it does to go out and take the original photography. It will save time by having an image naming system and computer directory plan before you start generating anaglyphs. There are many other applications, camera configurations, and software that utilize anaglyphic and other forms of stereographic imaging. Many of these can be found by searching on the World Wide Web.

3D photographer's comment—note that spacing of the cameras ranged from about 1 to 20 meters for this series of stereo anaglyphic images. (Focus left camera on nose, "click!" walk 5 to 10 paces to right, focus right camera on nose, "click!" ) Make anaglyph, trim foreground if necessary. Try different scales for distant features. The greater the distance apart the cameras, the more exaggerated the relief will be—at a distance. With increasing distance between cameras, objects in the foreground are lost to distortion, so trimming is usually essential. For examples, see the Mount Rushmore National Memorial images.

Viewing 3D Anaglyphic Photography

It is our experience that the best viewing of our 3D images, (particularly landscapes or objects in natural lighting) depends on the quality and type of glasses, and the environment of viewing. Most images are examined on a computer screen, and little can be done (without effort) to change the brightness of an image quickly and easily. Printed images can be moved to different lighting setting, but image quality depends on the type of paper and print quality.

Glasses can make a difference. Cheap glasses with paper frames given out at 3D movies work fine, however, having investigated the varieties available (low to high end), we find that more transparent varieties of cyan films work best. We found that Red-and-Green, and Red-and-Blue filters make viewing difficult, and image quality is lost. Red filters are fairly uniform, but the quality of cyan varies significantly. Cyan filters that transmit slight amount of red seem to work best on this anaglyph image process. Pale cyan 3D anaglyph and anachrome style glasses have worked best with our image development. Who know's what the future of the science will bring? For more information and, search the Web for 3D imaging sciences organizations and societies. There are many methods of creating anaglyphs and each variety works best with tailored glasses specific to the method. Our "non-technical" means of finding what worked best for us was purely "trial and error." In general, brighter light really makes a difference.