As you probably know, 'white color' is actually the combination of all the other colors, and 'black color' means the absence of any kind of light. You may already have heard about 'primary colors', and secondary colors, the second group being the result of mixing the primary colors in different proportions. This means that when you see 'white light', you are actually seeing light of all visible colors, but you understand that mix of colors as the color white.
It is possible to separate colors using color filters; a color filter allows the passing of light of a certain color, but blocks the rest. If you emit white light and make it go through a color filter, only that color part of the white light will pass through, which means that the light of that color will have the same observed result as white light. The same result will be observed with any color combination that is the result of mixing the color of the filter with some other color.
On the other hand, if the color of the light that goes through the filter has nothing to do with the filter color (these may be 'complementary colors'), it will not go through, and since no light goes through the filter, this will be perceived as 'black'.
This can be used to achieve the stereoscopic effect. What we want is to send different images to each eye, and we can use color combinations and color filters to send images (made from light) to one eye but not the other.
We can choose any combination of two colors that are not a mix of each other, and mix them on the screen. Using filters of different colors for each eye, we can make an image 'go through' for an eye but be blocked for the other eye.
You can view examples of anaglyph pictures by using the images search service of a search engine (using the term 'anaglyph'), or you can watch an example in the mini game below. As with all stereoscopic images or animations, caution is required, and you should take a rest when you feel eye strain (please refer to the page about 'precautions' for more detailed information). It is also suggested that you remain seated while playing
You require Adobe Flash player to play the next anaglyph game; the slider on the bottom in the game screen allows you to control the 'depth'.
The main advantage of anaglyph in 3D TV is that no special hardware is required. You can watch 3D stereoscopic movies in any color device with the aid of (normally) very cheap color glasses (red/cyan is probably the most used color combination, which is also the one required to play the mini game above).
The main disadvantage of this technique is that the color filters may let go through part of the light that was not intended for each eye (known as 'crosstalk'), which means that each eye sees some 'phantoms', which are partial representations of the image intended for the other eye. If the color filters worked perfectly, in the image below you would be able to see only one bar in each lens, but you will probably see a well defined bar, and some dark bar in each lens.
Also, since each channel represents the image intended for each eye with just a part of the color range, each eye receives incomplete information concerning the image colors; this also results in weird effects such as shinny parts that should not be shinny, and some motion effects.
