What is Dithering?
Dithering is the process of creating or approximating a color from other colors in a particular digital image. It is sometimes referred to as “color reduction” or “half toning” since this process is done by a particular program to display images using fewer colors than the original.
In the case of images with only black and white colors involved in the frame, photo imaging software may be able to “dither” the picture involved and produce a “third” or “gray” color out of the available black and white. In this example, dithering is done by the computer software to produce the gray color by translating other black and white pixels into gray. In this way, the digital image will lose sharpness and will appear “softer” on screen.
Dithering is also a common process used by various computer software or image display programs to literally reduce the number of colors in a full-color photo. A typical full-color photo will contain an almost infinite number of colors and hues, and in order for a particular program to reduce the number of colors and exclude the abrupt color transitions in the image, dithering may be done. And as with black and white photos, the process of dithering may also result to a reduction in image sharpness and/or image detail resolution. Some programs or display browsers are also not able to display all available colors from a particular full-color image and so may resort to dithering and approximate some colors to display the particular digital image. The resulting ‘dithered’ image in this case may be barely noticeable for some photos but in others, it may appear too “grainy” as colors pixels will have reduced quality. There are also some display monitors that can only display a minimal number of colors and so images are automatically “dithered’ and “color-reduced” by means of color and/or pixel substitution and approximation.