2. Basics of Image Processing

2.2 Picture Types

2.2.1 Basics

The user usually works with several picture types: bitmaps or monochrome pictures, gray pictures, RGB pictures, CMYK pictures and vector graphics.

Bitmaps, gray pictures, RGB pictures and CMYK pictures are called pixel or raster graphics. Every picture consists of little dots (called pixels), which are arranged in a raster, like on a computer monitor. These four picture types differ considerable in the number of usable colors and the amount of needed memory.

Pixel images - with the exception of bitmaps, which always occupy 1 Bit per pixel - can have different color depths. Most common is a color depth of 8 Bit. This means that every channel of the image needs 8 Bit or 1 Byte. Some devices like scanners or digital cameras are able to create pictures with a higher color depth. Therefore, PhotoLine supports a color depth of 16 Bit, 2 Bytes, per color channel, too. Additionally, PhotoLine can handle 32 bits per color channel. This format is mostly used with HDR (High Dynamic Range) images. HDR images can contain color values, that are smaller than 0% or larger than 100%, but only the range from 0% to 100% is visible. On displaying values outside that range will be reduced to that range.