Abstract: In one embodiment, a method for duplex scanning includes: illuminating a first side of an object with light of a first color from a group of colors; sensing the first color light reflected from the first side; illuminating a second side of the object opposite the first side with light of a second color from the group of colors simultaneously with the act of illuminating the first side with the first color light; and sensing the second color light reflected from the second side. In another embodiment, a duplex scanning method includes simultaneously illuminating each side of a document sequentially with each of multiple colors of light but in different color sequences for each side of the document so that the same color light does not illuminate both sides of the document at the same time.