I know that at least some of you frequent HDTV Almanac readers are old enough to remember when the NBC peacock revealed a major change in television technology. Overnight, we went from shades of gray on the TV screen to full color (or what was close enough to full color for us at the time). I still remember the first kid in our school to get color TV at home.

I’m sure I’m preaching to the choir here, but the way the wizards at the Sarnoff Labs managed to get a color display was to combine red, green, and blue sub-pixels. By varying the amount of light emitted from each of these three primary colors, you can make a full color image. But this approach has limitations. The phosphors used in a CRT or plasma screen or the color filters used in an LCD screen can limit the range of the colors that can be produced.

At CES, Sharp demonstrated new technology that makes a significant improvement in the color performance of LCD HDTVs. Instead of using just the standard red, green, and blue (RGB) sub-pixels, they added a fourth color: yellow. This helps improve color performance for yellow shades, especially the difficult gold metallic hues. Here’s a photo of two sets from the Sharp press conference:

Yes, I admit that it’s not a great photo. And I generally avoid showing photos that compare images because you can introduce additional limitations with the camera and the screen you use to view the image. But I think that most of you will be able to see a strong improvement in the yellows and oranges for the screen on the right.

Now, is this an important change? I’m not sure. The human vision system is very clever at adjusting for shifts in what we see. We know what color a lemon should be, so when you have the color off a little bit on your TV set, your mind still sees a lemon as a lemon. The average consumer does not seem to be too good at telling the difference between a standard definition DVD image and a high definition image, especially when there isn’t a second screen available for comparison. I expect that most people would not be able to tell you whether a given screen is RGB or RGBY, even though they could see the difference between the two when placed side by side.

The fourth sub-pixel is likely to increase production costs, as well as reduce the amount of light that the panel will produce. Overall, I don’t think that the average consumer will want to pay a premium to get RGBY technology, even though it does look great.

Posted by Alfred Poor, January 11, 2010 5:00 AM