Epson GT-6500 EN - Manual (Page 117)

In the color scanning mode, the data format setting defines tones for
each of the three primary colors, green, red, and blue.
Data format Monochrome Color
1 bit/pixel/color 2 grays 8 colors
2 bit/pixel/color 4 grays 64 colors
3 bit/pixel/color 8 grays 512 colors
4 bit/pixel/color 16 grays 4,096 colors
5 bit/pixel/color 32 grays 32,768 colors
6 bit/pixel/color 64 grays 262,144 colors
7 bit/pixel/color 128 grays 2,097,152 colors
8 bit/pixel/color 256 grays 16,777,216 colors
Specifying the data format determines the amount of image data in
each data block.
Note:
Even when the specified values exceed the capabilities of the
computer display or printer, data is sent according to the specified
format and quantity. Before scanning, you should consider how the
image data can be stored or processed.
ESC D and other commands
The data format selected by this command determines the effective
halftoning mode selectable with the ESC B command.
With multilevel data settings (more than 3 bits per pixel per color) the
halftoning modes are not effective.
Command Reference 3-23