SHARPNESS or DETAIL. The final setting is sharpness or detail. Now, pray tell, who in their right mind wouldn't want the sharpest, most detailed picture they could get? And since there is a control that lets you turn it up, why not turn it up? That's what many folks do, and of course it's exactly the wrong thing to do.
The sharpness control adds processed information to the picture that is NOT part of the original video signal. It adds artificially highlighted edges, and makes the picture look less natural than it otherwise would. This is most evident along the continuous edge of a dark object against a middle-toned background. When sharpness is overdriven the dark edge will be outlined by a white ringing effect that increases contrast just along the edge of your dark object. That edge "highlighting" effect is created by the sharpness control. It is an artificial manipulation of the image. It wasn't in the original scene, and it shouldn't be on your screen either.
On most televisions, the optimum setting for sharpness is zero. On many digital projectors, the optimum setting is either in the low or middle part of the scale. Picture tube televisions and digital projectors behave differently in this regard; on a digital projector it is often possible to fuzz the image by setting sharpness too low.
