A common perception of sharpness is that this parameter changes the resolution of the image. Purely from a technical point of view, this cannot be true. Modern TVs have a fixed number of pixels, that is, resolution. Even if the original resolution was lower or higher, the TV scales the picture to its resolution. In fact, sharpness is largely a psychological ploy.
By adjusting the sharpness, you change the contrast of the edges. The contrast of the edges, in turn, creates the feeling that the image has become clearer.
That is, the viewer perceives the picture more detailed and clear, although its resolution does not change in any way. Sharpness seems like a great way to increase image clarity, but if you overuse this option, it turns out that excessive use of this option can lead to negative consequences.
Excessive use of sharpness can cause ghosting around the image. Especially, such a negative effect is enhanced if the image was initially grainy. That means when your sharpness is set too high, you could lose some of the crisp detail of that fancy 4K TV. Sharpness is one of the many picture settings on your TV , like brightness, contrast, and color. Turning them all up might seem like a great idea. After all, who wants a picture that's dim, colorless and dull, right?
In reality, maxing out any of those adjustments can ruin your picture, making it less accurate and limiting the potential of the best TVs. An image that's too bright or garish is easy to understand, but sharpness takes some explaining. Buckle up. On nearly all TVs, the sharpness control adds something called "edge enhancement. The edges in the image are enhanced, essentially by adding a thin outline or halo to them.
This makes them more visible. Left: the original image. Right: the edge-enhanced "sharper" version. The "halo effect" is what the sharpness control adds. Take a look at the side-by-side images above. The left image is the au naturel version. The right has significant amounts of edge enhancement added. Note the outline around the buildings. While the left image might appear, at first glance, "soft," it actually isn't.
The picture below is a close-up of the "sharpened" edge-enhanced version. As you'll see, a sort of white halo appears around distinct edges. The problem is that the halo shouldn't be there -- and it's replacing what should be.
It may not seem like a big deal in this image, but with most content that halo is covering the actual detail. Additionally, it often brings out grainy noise in other parts of the image. See how much cleaner the left image looks compared to the enhanced. Edge enhancement definitely gives the image a certain look: It can provide the appearance of more detail. Most TVs have their sharpness controls turned up in the default picture modes, so we're used to this faux-detail look.
While unenhanced images can look soft by comparison, especially at first, they're actually more detailed because they show fine textures in walls, pores on faces and tiny hairs -- all of which can be hidden by too much edge enhancement. Get CNET's comprehensive coverage of home entertainment tech delivered to your inbox.
This should be the setting where no sharpening or softening is applied. Softening an image electronically is actually pretty easy. The image at the top shows what happens when the computer applies a softening filter. Just like defocusing a real lens, everything seems blurry and detail is lost. But what about sharpening? On the other hand, you can make the details that do actually exist seem clearer.
However, the details of the background seem to pop out a lot more. What you do is, find any place where two colors meet and make one edge a little lighter and one a little darker. Take a look:. That added bit of contrast makes everything seem sharper. Be careful not to oversharpen or everything will take on a grainy appearance.
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