Epson ES-1000C Reference Manual page 24

As you increase the amount of data, you dramatically increase the
number of minute differences in color you can represent.
Bits per pixel
1 bit/color/pixel
2 bits/color/pixel
3 bits/color/pixel
4 bits/color/pixel
5 bits/color/pixel
6 bits/color/pixel
7 bits/color/pixel
8 bits/color/pixel
1-10
Overview
Monochrome shades
2
4
8
16
32
64
128
256
Colors
8
64
512
4,096
32,768
262,144
2,097,152
16,777,216