Avision AV620CS+ - Manual (Page 36)

AV620CS Plus 4-11
Gray (4096 levels gray scale/Internally)
Usually, a single-channel image consists of at least 8-bit or 256
levels of shades of gray in an image. However, AV620CS Plus
with 12 bits produces a Gray image with 4096 shades of gray
between pure black and pure white. Gray is the best choice of
image if you wish to scan a black and white photograph. With
12 bits of color information per pixel, the disk space required to
save a gray image is eight times more than lineArt and 1/3 of
that required to save a 24-bit true color image.
Figure 4-7 Halftone Image
256 Colors
The 256 colors image provides 256 levels of color hues. The
disk space required to save an image in 256 colors is 1/3 of
that required to save a 24-bit true color image.
Figure 4-8 Halftone Image