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Every TV has a lot of settings to adjust the picture quality. While you change your TV photo mode can do a lot to make it look its best, there is one feature that deserves special attention. It’s called “Sharpness” and while it may seem simple, it doesn’t actually do what you might think. Believe it or not, changing this setting down can actually improve the picture on your TV.
I completely understand that you want to get the most out of your data. 4K TVbut the fact is that the sharpness control does not actually increase the sharpness of the TV. In most TVs it is actually masks fine detail. This means that if your sharpness is set too high, you may lose some of the sharp detail that is 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 lower 20% or so.
It’s understandable if you’re confused. An image that too light or garish is easy to understand, but sharpness requires some explanation. Don’t worry. I’ll explain it all below.
If you want to dive deeper into the best settings for your specific TV, read more about the best picture mode and the effects of changing these additional settings.
Sharpness means edge enhancement
On almost all TVs, the sharpness control adds something called “edge enhancement.” It’s exactly what it sounds like. It enhances the edges of the image, essentially 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.
Look at the side by side images above. The left image is the Naturally version. On the right, a significant amount of edge enhancement has been added. Note the outline around the buildings. While the left image may appear “soft” at first glance, it is not.
The image below is a close-up of the “sharpened” edge-enhanced version. As you will see, there is a sort of white halo around several edges.
Note the slight halo along the edges of the buildings. That’s edge enhancement, and it can mask fine detail and make a TV picture look less natural.
The problem is that the halo shouldn’t be there — and it’s replacing what should be there. It may not seem like a big deal in this image, but in most content, that halo obscures actual detail. Plus, it often brings out grainy noise in other parts of the image. Just look at how much cleaner the left image looks compared to the enhanced one.
Edge enhancement definitely gives the image a certain look: it can appearance of more detail. Most TVs have their sharpness settings turned up in the standard picture modes, so we’re used to this fake-detail look. Dynamic, Vivid, or Sports modes tend to have a lot of edge enhancement, but they’re not the only modes that do it.
While unenhanced images may look soft in comparison, especially at first, they are actually more detailed, showing fine textures in walls, pores in faces, and tiny hairs. All of these can be hidden by too much edge enhancement.
What is the best sharpness setting for my TV?
The easiest way to check this is to put your TV on the Movie or Cinema picture preset and see where the sharpness control is in that mode. Whatever that number is, it’s a good place to start.
Read more: How to set up your TV
Want to fine-tune it? While watching different content, especially 4K if you have a 4K TV, turn the control down from that starting point and see what happens. Does the fine detail disappear? If so, that’s too low. Ideally, you can find the spot that has the most actual detail and the least extra noise. Don’t be surprised if that number is 0.
Some TVs will actively soften the image when you set the sharpness control to zero (or even below 50 in some cases). This can be done to provide a way to reduce noise in lower quality sources, but I’d be shocked if it was ever used for that purpose. Just something to keep in mind. If the image suddenly looks blurredthat is definitely too low. There is a sweet spot with every tv, it’s just a matter of finding it.
A Blu-ray disc, such as the Spears & Munsil UHD HDR benchmarkhas patterns that make it easier to find the exact sharpness level for your specific TV.
It is possible, though rare, that you have a TV with permanent edge enhancement. Even if you turn the sharpness control to zero and go through all the settings (and picture settings) on your TV, you may still see edge enhancement or other processing. This was more common on older TVs, though. It is quite rare these days.
Read more: When to Call a Professional to Change Your TV Settings
What about other visual controls?
Lots of TVs and some high-end projectors have processing features separate from the sharpness control. These are usually found deeper in the settings menus or in separate “advanced” sections. Some of these can improve apparent detail without adding unnecessary amounts of edge enhancement. Others, of course, do more harm than good.
The different steps in Samsung’s AI Upscaling process.
Part of this is due to the increase in overall processing power available in mid- and high-end TVs. For example, Samsung, LG and Sony have talked about using AI for their upconversionwhich means that you still get a reasonably good image with a lower resolution on a high-resolution television.
There’s no blanket advice here. If your TV has these resolution/detail enhancement features, try them all out to see what they do. Sit close to it and see if it adds noise, edge enhancement, or makes the picture look sharper. Purists will probably want to leave these features turned off, especially with high-end content like a 4K Blu-ray, but for some content it can help.
If you have a Blu-ray player, you can get a special disc that will help you fine-tune the picture. One of the most comprehensive is the Spears & Munsil UHD benchmark, which CNET uses in our TV Lab. Note that this requires a 4K Blu-ray player.
Why Sometimes You Can’t Turn Down the Sharpness
Sometimes the edge enhancement is in the source. This was common on early DVDs, where edge enhancement was added to make them “pop”. If it’s in the source, there’s nothing you can do about it. It’s just something to keep in mind when trying different settings, don’t just use one source or program.
There are also sources, generally low-quality video such as standard-def TV channels or even VHS tapes, that can benefit from a TV’s detail enhancement circuitry. These sources are so soft and low-resolution to begin with, that they can look much better enhanced when blown up to the size of today’s large televisions.
TV manufacturers love edge enhancement, mainly because it makes their TVs look super detailed when you look at them in a store. Some cheap TVs may have unbeatable edge enhancement. So no matter how low the sharpness control is, there is always edge enhancement. Unfortunately, there is not much you can do about it.
Does the sharpness look strange? Give it a few days
Now if you go to your TV and turn the sharpness control all the way down, the picture will look absolutely soft. Just like with high color temperaturesAnyone who isn’t used to making fine adjustments to their TV’s controls has become accustomed to a certain “look” to their TV’s picture. So at first, even the correct sharpness setting can seem soft, especially if your TV has been in Vivid or Dynamic picture modes.
Try the new, lower sharpness setting for a few days. If you’re not happy with the way the unenhanced image looks, that’s fine. Then turn it back up. But I bet if you do, the “original” setting will look weird and the “lower” sharpness mode will look much better.
Editor’s Note: This story was first published in 2015, but has, ahem, sharper with current information, links and more.
In addition to his work in audio and display technology, Geoff hosts photo tours to cool museums and locations around the world, including nuclear submarines, aircraft carriers, medieval castles, epic 10,000 mile road trips and more.
Also check out Budget Travel For Dummieshis travel book and his bestselling science fiction novel about city-sized submarines. You can follow him on Instagram And YouTube.
