Tuesday, 14 August 2007

Interesting Artical for Interface Designers

Google Won't Go Dark to Go Green Eco-friendly Web developers are designing in dark colors to save energy. But going black only saves watts on old-style CRT monitors, not LCDs

For most Web site publishers, the phrase "gone dark" has the worst of all connotations. It means a site is no longer running. There's been a system malfunction, a power failure, a protest, or—worst of all—a permanent company shutdown. But for a new crop of eco-friendly Web site designers, "going dark" is taking on a new meaning. It's the new way to go green.

The online buzz over "going dark" began in earnest last January after Mark Ontkush, a self-described "green computing evangelist," wrote a blog post concerning environmentally friendly Web design. Ontkush claimed that if a popular site such as Google switched its home page background color from white to black, it could save hundreds of megawatt hours a year. He based his claim on the fact that certain types of monitors use less energy to display black than white screens. And according to the Environmental Protection Agency, cathode-ray-tube (CRT) monitors and even some flat-panel screens use less energy to display black or dark backgrounds.

Web site designers quickly created a host of black-background Google home pages in response. With names such as Blackle, Darkoogle, and BlackWebSearch.com, the sites initially appear to be Halloween-themed versions of Google's annual April fools' joke. Each, however, does return real Google search results.

Google got wind of its dark alter-egos and came to the defense of its choice of a white background. In an Aug. 9 blog post, Google's green energy czar Bill Weihl wrote that the flat-panel computer screens most common in the U.S. don't save energy displaying black backgrounds. Weihl referred to a test run by an Australian electronics graduate student comparing the power consumption of Blackle and Google on 27 different monitors. On average, CRT monitors saved 10.8 watts per hour using Blackle.

However, liquid-crystal display (LCD) monitors largely used the same or, in several cases, several watts more energy to display the black background. The results were published Aug. 8 on Australian tech news site Techlogg. "We applaud the spirit of the idea, but our own analysis as well as that of others shows that making the Google home page black will not reduce energy consumption," wrote Weihl.

CRT and LCD monitors use different amounts of energy to produce a black screen due to their design, says Scott Gray, a product manager at Hewlett-Packard's commercial display business unit. CRT monitors produce an image by firing a stream of electrons at phosphorescent material within the screen. The various frequencies with which the electrons hit the phosphorescent material produce the unique colors. Black is the default color of the phosphorescent material when no electrons are hitting it and the electron gun is essentially off. "The CRT is using less current with a black screen so there is less electricity used," says Gray. "The peak current is with a bright, well-lit image."

LCD screens, on the other hand, are lit via fluorescent tube lights located above or behind the LCD screen. The screen scatters the light, creating the picture. When an LCD screen is on, the lights are also on. "Black is not created by the absence of electricity or by turning off the light," explains Gray. "In a lot of cases, a black screen looks purple because the colors are created by mixing the right pixel elements in the LCD together at the same time.

Google doesn't see much advantage to the black screen, given the dominance of LCD monitors in high tech countries such as the U.S., Japan, and Korea. Ontkush and other eco-computing enthusiasts, however, still see "going dark" as having planet-saving power for the 25% of the world where older CRT monitors are the norm.

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