TV manufacturers have found that one of the most reliable ways to get consumers to buy a new TV is to push more pixels. The big jump was from Standard Definition (480 horizontal pixels using interlaced scanning) to High Definition (1080 horizontal pixels using progressive scanning). Today, we’re being pushed to buy “4K” TVs, but that definition switches the emphasis from horizontal pixels (there are 2160 of those) to the spec’s vertical pixels (3840) because it’s so much bigger than 1080.
Recently, however, an entirely new buzzword has entered the manufacturer’s vocabulary: High Dynamic Range (HDR). Suddenly the discussion isn’t just about more pixels, but better pixels. At its most basic, HDR delivers greater contrast between light and dark areas of a video image. How does that work and how important will it end being to your TV enjoyment? I shall endeavor to enlighten you.
How HDR works
If you’re familiar with High Dynamic Range at all, it’s likely via a setting on your smartphone or digital camera. As its name implies, the feature increases the dynamic range—the ratio of light to dark—in your photographs. It accomplishes this by photographing the subject three times at different exposures, doubling the light in each picture. The three images are then blended into one (in a program such as Photoshop, if the device doesn’t handle it internally) that retains the darkest and brightest parts from the first and third exposure, respectively. The result should be a brighter, more detailed picture that’s much closer to what your eye sees.
The idea behind HDR video is similar: It increases the range of brightness in an image to boost the contrast between the lightest lights and the darkest darks. If you’re having difficulty grasping how that translates into a more realistic image on your screen, think of the subtle tonal gradations a fine artist creates in a charcoal drawing to build the illusion of volume, mass, and texture, and you should begin to get the picture. But HDR doesn’t just improve grayscale; its greater luminance range opens up a video’s color palette as well. “Basically, it’s blacker blacks, whiter whites, and higher brightness and contrast levels for colors across the spectrum,” says Glenn Hower, a research analyst at Parks Associates.
The result is richer, more lifelike video images. Rather than washing out to white, as it would in conventional video, a ray of sunlight reflecting off a lake in HDR will gleam, and a bright cloud will appear soft and cottony. Basically any image your current TV would render shadowed, dull, muddy, or bleached out will look nuanced, vibrant, and strikingly realistic in HDR.