Epson GT-6500 EN - Manual (Page 34)

Color setting
Setting the color determines the method used for scanning.
If you select monochrome scanning, you can specify either red (R),
green (G), or blue (B) as the dropout color. The scanner then ignores
the specified dropout color when scanning a document. For example,
if you want to read a document that has been marked with red pen,
you can select the dropout color to be red; the scanner then ignores the
red markings and scans only the original document.
If you select color scanning, you can choose page scanning, line
scanning, or byte scanning. Page scanning scans the entire page three
times; once for each color. Line scanning scans all three colors line by
line. Byte scanning scans byte by byte.
1-20 Overview