When acquiring an image, it is a good idea to set the borders of the scanned area as tightly as possible around the object of interest. The larger the area scanned, the larger the file size. Color Depth or Pixel Depth Color depth indicates how many bits of data are kept per pixel in a graphic image. It determines how many colors are available to the image in the color palette. Most image file formats store color palette information in the header section of the file.
Color depth is given in the third number of a pixel dimension.
For example, an image with a dimension of 800x600x24 has a pixel dimension of 800 pixels wide by 600 pixels high and 24 bits of color information are stored per pixel. An 8 bit image supports 2 to the 8th or 256 colors, a 24 bit image 2 to the 24th or about 16 million colors. Due to variations in how graphics programs and conversion algorithms work, it is best to start off with as much color depth as possible. Most modern scanners can acquire images with a color depth greater than 30 bits. This is especially important with full color photographic images.