Gadgetwise Blog: Why You Don’t Need a 4K TV

The Sony KDL-55W900A offers more colors than a standard TV.

I was asked for some advice about buying a television this weekend, and the one thing I could say with certainty was, “Don’t buy a 4K TV.”

These 4K televisions, if you aren’t familiar with them, are sets with four times the resolution of current, top-of-the-line 1080p TVs. That means there are many more lines on the screen, which you would think would give it a clearer, sharper picture.

But at a common viewing distance, say six feet or more, it doesn’t (with an exception I’ll get to). These sets sell at nose-bleed prices of $5,000 to $10,000, and what you gain  is practically nothing. The reasons are many.

Foremost, the eye can take in only a finite amount of resolution. From a good 6 to 10 feet seating distance, you won’t see a significant difference between a 1080p TV and a popular size 4K TV.

To explain just what matters when buying a TV, I called Joel Silver, founder of the Imaging Science Foundation, which consults with the TV industry on manufacturing displays.

The most important feature is “dynamic range.” Looking at the contrast ratio is similar, but not quite the same,  Mr. Silver said. That’s because manufacturers can raise the contrast ratio by making the whites really bright, when the darkness of the blacks is what’s important. It’s best to go to a store and look for yourself.

The next most important feature is color saturation. “Are the reds really red?” said Mr. Silver. More specifically, are they as red as they should be? Too red won’t do, either.

Which leads to No. 3, color accuracy. Do skin tones look as they should?

“The last thing we look at is resolution,” said Mr. Silver.

You may be getting the idea that the most important thing here is the color quality. That’s the right idea. And that’s where 4K has some promise in the future, said Mr. Silver.

Most 4K TVs are likely to include a format called xvYcc, which lets them show a wider range of colors than current TVs. Of course, you’ll also have to get your movies or TV in xvYcc for that to pay off. And that might be a long time coming — after all, the TV industry has been talking about xvYcc since at least 2007.

You can see the increased color in a limited way right now, though. Sony’s KDL-55W900A TV, which is 1080p (a 55-inch model lists for $3,300), has the expanded color capability. Sony pictures is also rereleasing old titles remastered for improved color as the Mastered in 4K series. When they are paired with the proper Blu-Ray player, you should see a difference.

There is one exception that I said I would get to: If you are getting a giant TV — 85 inches or bigger — and you plan to sit very close to the screen, a higher pixel count means you will see pictures instead of pixels. TV with 4K (and even 8K is in development) can be viewed from just a few feet away because the resolution is so high.

Now the question is whether you want to sit three feet from a giant TV.