Implicating sepia -> monochrome.

Reason:

Sepia is a dark brown-grey color.
one color or shades of one colo

If an image is truly Sepia toned, (by a strict Sepia definition), it must technically be completely monochrome.
This means that it only contain shades of brown, much like a black and white photograph only contains shades of gray.
http://www.easyelements.com/what-is-sepia.html
To define Sepia in short: A picture is Sepia toned if it is a monochrome image with a dark brown tint.

+1 to that

Well generally when you think of monochrome, you think of black and white but since there is an actual black_and_white tag then I would say they are the same thing because monochrome means only 1 color, obviously a picture will have different shades of that color or it would be a blank page lol. I say implement!