Rasterschmalen

Rasterschmalen is a term used in digital imaging and computer graphics to describe the process of reducing the number of distinct colors in an image while attempting to maintain the visual appearance of the original. This is often done to decrease file size or to make an image compatible with displays or devices that have limited color capabilities. The core idea is to map the colors present in the original image to a smaller, predefined palette of colors.

There are several algorithms used for rasterschmalen. One common method is dithering, where strategically placed pixels of available colors are used to simulate colors that are not in the target palette. This can create a grainy or patterned effect, but it often preserves more detail than simpler color reduction methods. Another approach is to simply round the existing colors to the nearest color in the target palette, which can lead to noticeable banding or posterization where smooth color gradients existed in the original. The choice of palette and the dithering algorithm can significantly impact the quality of the resulting image. Rasterschmalen is frequently employed when converting images to formats like GIF, which traditionally supported a limited number of colors, or for web graphics where bandwidth is a concern.