The Sharpness Control Doesn't Do What You Think

Every TV has a bunch of settings to adjust the picture quality. While changing your TV's picture mode can do a ton in getting it to look its best, there's one feature that deserves special attention. It's called "Sharpness," and while that seems straightforward, it's actually not doing what you'd think. Believe it or not, turning this setting down can actually improve your TV's image. I totally understand wanting to get the most detail from your 4K TV , but the fact is, the sharpness control doesn't actually increase the TV's sharpness. With most TVs, it actually masks fine detail. This means that when your sharpness is set too high, you could lose some of the crisp detail possible on that new TV. In some cases, the best sharpness setting is actually zero, while on most TVs the setting is best in the bottom 20% or so. It's understandable if you're confused. After all, an image that's too bright or garish is easy to understand, but sharpness takes some explaining. Don't worry. I'll explain it all below. If you want to dive deeper into what settings are best for your specific TV, learn about the best picture mode and the effects of changing these additional settings . More Tech Tips Here's How to Get the Most Out of Your New TV How to Make Speech on Your TV More Understandable Your TV Could Look a Whole Lot Better: 9 Setting Changes for the Best Picture Sharpness means edge enhancement On nearly all TVs, the sharpness control adds something called "edge enhancement." That's exactly what it sounds like. The edges in the image are enhanced, essentially by adding a thin outline or halo to them. This makes them more visible. Enlarge Image Left: the original image. Right: the edge-enhanced "sharper" version. The "halo effect" is what the sharpness control adds. Geoffrey Morrison/CNET 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. Enlarge Image Notice the slight halo along the edges of the buildings. That's edge enhancement, and it can mask fine detail and make a TV's image look less natural. Geoffrey Morrison/CNET 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. Dynamic, Vivid, or Sports modes