A New Color Brightness Standard for Video Projectors?
Thursday, January 31st, 2008When people shop for projectors they compare a lot of information. Since so many people shop online rather than comparing hundreds of models in a brick and mortar store, they often have to rely only on manufacturers published specifications to make their ultimate decision. Most of the specifications you see published are standardized in one way or another to keep manufacturers and resellers honest.
Brightness, for example, is reported as “ANSI lumens”, the ANSI stands for the American National Standards Institute. Contrast is also a standard, though the methods of calculation (ie. full on/ full off versus “real world” measurements) are sometimes not equal.
But the people at 3LCD, an advocacy group for LCD technology, believe that there is more to the picture quality story than just brightness and contrast. Just a few days ago they announced support for a new “Color Brightness” standard which they feel addresses another important issue to end users; color accuracy. While the new standard will not exactly specify how accurate color is, it will illustrate the ability of the projector to produce color, which factors heavily into the equation.
When the standard is adpoted users will see two ratings for brightness. Here are two examples from the people at Lumita who have done the research.
Example Projector with Good color performance:
- White 1800 lumens
- Color 1800 lumens
Light Output specification:
Example Projector with Poor color performance:
- White 1800 lumens
- Color 900 lumens
Light Output specification:
Why the New Color Brightness Standard?
Most likely the push from the folks at 3LCD has to do with the technology battle between DLP (Digital Light Processing) and LCD (Liquid Crystal Display). The two technologies make up nearly 50% each of the home theater and business projector markets (with LCOS a distant third), but each camp continues to work to get a larger share of the market. The advantage of LCD which is most often cited is color accuracy, a characteristic that currently does not have a standardized metric. That’s where Color Brightness comes in.
Here’s an excerpt from a January 2008 press release from 3LCD:
“3LCD today confirmed its support for the new Color Brightness metric. The Color Brightness metric is being submitted to the ISO for approval as an update to the International Standard for light output measurement. Color Brightness specifies a projector’s ability to deliver color. The Color Brightness metric addresses the failure of current projector specifications to measure color performance, allowing purchasers to evaluate color performance at a glance. 3LCD joins a growing list of industry players supporting the new metric.”
Though it may have been born of the battle between LCD and DLP, the standard will also give consumers insight when comparing to LCD projectors. It also gives the folks at DLP a specification to target for in the image quality debate. New DLP technology has greatly improved color accuracy already.
Exactly What is Color Brightness?
If you are interested in the technical talk about Color Brightness, here is a little more from the 3LCD press release we quoted earlier:
“Today all video, DVD, HD, digital camera and computer signals are encoded in an RGB color space. In all of these devices and in the world around us, red, green and blue added together equal white. If this is not the case, a full and balanced range of color cannot be reproduced. Color Brightness measures the brightness of red, green and blue, just like the input signal. If a projector can produce bright red, green and blue that combined equal the brightness of white, true, accurate and balanced color is possible. If Color Brightness does not equal the White Brightness, accurate color reproduction is impossible.
…The new proposal modifies the International Standard IEC 61947-1 to provide purchasers with additional information on a projector’s color performance. The existing brightness standard provides consumers and purchasing managers a critical metric often communicated as “lumens” or “ANSI lumens.” The updated specification will not affect this current white illuminance measurement. It simply adds another metric that specifically measures color illuminance. Color Brightness is measured using the same industry-standard methodology. The new number is also reported in lumens, providing a familiar and relative number. If both the white illuminance (brightness) and color illuminance (color brightness) are equal, the projector will accurately deliver the proper energy to the primary colors of red, green and blue exactly as they are in the source video signal.
[ photos: Images from Lumita .pdf ]
Who Will Use the Standard?
Epson and Sony are two of the larger manufacturers on board for the new standard. 3LCD group also support implementation of the new standard, and issued the press release that initiated our discussion today.
