Anaglyph images
At the Anaglyph images the two fields are printed on top of each other, with both fields colored in complementary colors. An „anaglyph“ basically refers to any stereo image in which the two partial images are shown simultaneously on the same surface. Strictly speaking, the polarization projection is also an „anaglyph projection“.
However, „anaglyphic“ usually means a color anaglyphic representation: different color filters are used in 3 D glasses to separate the two individual images, and the lenses are almost always colored red in front of the right eye and green in front of the left. When viewing the photo or film, the red filter erases the red color image and the green image turns black – the green filter erases the green color image and the red turns black. Since both eyes now see different images, a spatial image is created again in the brain.
In the late 1970's, Stephen Gibson greatly improved the color anaglyph technique with his patented „Deep Vision“ system, which uses different filter colors: red in front of the right eye and blue in front of the left. The Danish company „Color Code“ now also offers its own color anaglyph system. The filter colors of the „ColorCode“ glasses are blue in front of the right eye and yellow in front of the left. For the feature film „Journey to the Center of the Earth“, another color anaglyph process („Trio Scopics“) was introduced in England in 2008, with green in front of the left eye and magenta in front of the right.
Using the red cyan method, the procedure for creating a three-dimensional image is explained here using the diagrams opposite:
In the first line you can see the two colored images for the left and right eyes (also seen with parallel vision in this illustration).
The second line makes it clear that only the red channel of the left image, as well as blue and green channels of the right image, are used for the calculation.
The finished, colored anaglyph in line three is created by combining the red channel of the left image and the blue-green values of the right image.
This method is not perfect. When looking through red-cyan glasses, the two left balls are particularly problematic because they have the filter colors red and cyan, which leads to annoying effects when looking at them.
While red-green and red-blue glasses each use only two color channels of the available red, green, blue channels, cyan consists of a mixture of green and blue, which, together with the red filter, brings all three colors into play (in the case of blue-yellow glasses, the same applies because yellow is produced from red and green light).