formula lenses work well with black and white, but can provide excellent results when the glasses are used with conforming "anachrome friendly" images. The US Geological Survey has thousands of these "conforming" full-color images, which depict the geology and scenic features of the U.S. National Park system. By convention, anachrome images try to avoid excess separation of the cameras and parallax, thereby reducing the ghosting that the extra color bandwidth introduces to the images. Traditional anaglyph processing methods One monochromatic method uses a stereo pair available as a digitized image, along with access to general-purpose image processing software. In this method, the images are run through a series of processes and saved in an appropriate transmission and viewing format such as JPEG. Several computer programs will create color anaglyphs without Adobe Photoshop, or a traditional, more complex compositing method can be used with Photoshop. Using color information, it is possible to obtain reasonable (but not accurate) blue sky, green vegetation, and appropriate skin tones. Color information appears disruptive when used for brightly colored and/or high-contrast objects such as signs, toys, and patterned clothing when these contain colors that are close to red or cyan. Only few color anaglyphic processes, e.g. interference filter systems used for Dolby 3D, can reconstruct full-color 3D images. However, other stereo display methods can easily reproduce full-color photos or movies, e.g. active shutter 3D or polarized 3D systems. Such processes allow better viewing comfort than most limited color anaglyphic methods. According to entertainment trade papers, 3D films had a revival in recent years and 3D is now also used in 3D Television. Depth adjustment The adjustment suggested in this section is applicable to any type of stereogram but is particularly appropriate when anaglyphed images are to be viewed on a computer screen or on printed matter. Those portions of the left and right images that are coincident will appear to be at the surface of the screen. Depending upon the subject matter and the composition of the image it may be appropriate to make this align to something slightly behind the nearest point of the principal subject (as when imaging a portrait). This will cause the near points of the subject to "pop out" from the screen. For best effect, any portions of a figure to be imaged forward of the screen surface should not intercept the image boundary, as this can lead to a discomforting