Sharpness could more accurately be called "artificial edge enhancement," and generally only improves the look of lower-quality signals like standard broadcast, cable, and satellite programs. Increasing the sharpness is like turning up the treble control on your receiver; you may think you're getting more detail, but the result is definitely not more accurate. Having Sharpness set too high often creates halos around the edges of objects onscreen. Many DVD movies already have edge-enhancement added during mastering, so you can generally turn Sharpness nearly to zero for your DVD input. Sharpness is also not needed for most HDTV sources.