This paper is another kind of standard paper, but has both sides dyed with ink. When this is done properly, this requires a second inking process, but in cheaper versions of duo paper (particularly in China) the fibers themselves are dyed to save ink and money. It can be different colors on each side of the sheet, or it can also be the same color on both sides. This paper is more expensive than single color standard because of the second inking run, but less expensive than Tant. Duo is also only available in complimentary color combinations as well as the same color on both sides. Because of the extra layer of ink it is the thickest of the standard sheets measuring .076 millimeters per sheet.