What is 10-bit Color?

Yaseen Abdalla wants to know what 10-bit color means in an HDTV's specs.

Deep color--also known as 10-, 12-, and even 16-bit color--is both a a major image quality enhancement and a load of hype.

Home HD video signals (including Blu-ray) use 8-bit color, meaning that for each pixel, the signal contains eight bits for each of the three primary colors, or 24 bits total. Since there are 256 possible 8-bit binary numbers, you get 256 shades each of red, green, and blue. Combine the three together, and you get 16,777,216 possible colors (256 cubed).

That sounds like plenty, and to the naked eye, it is. But subtle differences between those 256 shades, impossible with 8-bit color, can help create depth and a sense of reality.

That's where deep color comes in. With 10-bit color, you get 1,024 shades of each primary color, and over a billion possible colors. With 12-bit, that's 4,096 shades and over 68 billion colors.

When you watch a movie digitally projected in a multiplex, chances are it has the same 1920x1080 resolution as Blu-ray. But a Blu-ray disc won't look anywhere near that good projected onto a 50-foot screen. Part of the reason: The theatrical presentation uses 12-bit color (10-bit for 3D). Film, being analog, doesn't have a color-depth limitation and can theoretically offer an infinite number of colors.

So where's the hype? No matter what your HDTV can do, you're probably never going to see any 10-bit content on it. Neither broadcast HDTV nor Blu-ray support deep color. If a studio released a movie on Blu-ray with 10-bit color, that disc wouldn't work on any existing player. It would, in effect, be a whole new format incompatible with any current disc player.

This brings up one of the major disadvantages of digital media: Although the technology improves at a faster rate than analog, you can't take advantage of that improvement without creating a whole new standard and breaking backward compatibility. Audio cassettes improved considerably in quality over 35 years, yet the best of the last cassettes would still play on the earliest player. You won't see that with digital media.

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