Display calibration

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TECHNOLOGY
High-definition TVs revive the house call
Skilled technicians help coax dazzling displays from today's highly complex sets
By Alex Pham
Tribune Newspapers: Los Angeles Times
Published March 19, 2005
Hagai Gefen spent thousands of dollars on a home entertainment system, but it wasn't picture perfect.
So he called in Joe Kane, who tunes television pictures the way piano tuners find the perfect pitch of A. Kane and a growing breed of technicians like him rely on their highly trained eyes to coax crisper pictures, richer colors and finer details out of the high-tech television sets anchoring more and more living rooms.
Gone are the days when twiddling the rabbit ears would tease a better picture from the snow on the screen. Today's high-definition TVs render dazzling, theater-quality pictures, but the technology inside has become mind-bogglingly complex. An improperly adjusted set can produce jaundiced, hazy, lifeless images.
Kane and his ilk make it right--for fees that range from $225 to well over $1,000.
"Technology may be at our fingertips, but many people don't know what buttons to press," said Joel Silver, president of the Imaging Science Foundation, an organization founded by Silver and Kane that trains and certifies calibrators.
"The old technology was mature and forgiving," Silver said. "So when a set was badly adjusted, it still looked OK. Now, with high-definition, there's no place to hide."
And because images are viewed and appreciated by human eyes in lighting conditions that can vary dramatically from living room to living room, there's only so much that machines can do to create a picture that's perfect for every home.
"In a completely dark room, I can come up with equations for what colors will always look like to the human eye," said Mark Fairchild, professor of color science and director of the Munsell Color Science Laboratory at the Rochester Institute of Technology in Rochester, N.Y.
"But in the real world, you have windows, different lighting, different room sizes, and our knowledge of color perception starts to break down. That's where we need a human to come in, look at your TV and tell you why it looks funny."
Human eyes have the ability to discern minute changes in color and light, said Dr. Michael F. Marmor, professor of ophthalmology at Stanford University School of Medicine. "Most people are pretty darn good at detecting fairly fine gradations in color," he said.
Gefen, for instance, knew his TV system, set up in the converted garage of his Woodland Hills, Calif., home, wasn't right. He just wasn't sure why or how to fix it.
But he was confident Kane would be. Gefen, who has a business that makes home theater components, was well aware of Kane's reputation.
"Joe is the master of color," Gefen said as he awaited Kane on a recent Monday afternoon. "He has a very good eye."
Kane arrived, lugging a laptop, a light meter and a small black case stuffed with software. His assistant, Marshall Bennett, trailed.
Gefen fired up his $12,000 Samsung front-projection television.
Everyone in the room marveled at the picture quality. Everyone, that is, except Kane.
"It's not very bright," Kane said. "Let's get a reading."
Bennett set up the spectra-radiometer, which measures the light reflected by the 8-foot-wide screen. "Eight foot-lamberts," Bennett called out. It should have been nine.
Among Kane's tools is a DVD that he popped into a computer hooked to the TV. The DVD contains dozens of test patterns, created to show the flaws of the TV's capabilities. Kane pulled up one called Ramps & Steps. A checkerboard of blacks, grays and whites, it shows whether the contrast is set correctly.
"I'm looking at the entire dynamic range," Kane explained. "If the contrast is too high, like it is now, it removes the details above the white level."
As he ratcheted down the contrast, blocks of bright white suddenly acquired more depth and warmth, so what was once a big, indistinguishable block now is divided into bars of varying shades of white.
And so it went over the next three hours as Kane delved deep into the recesses of Gefen's TV, unearthing its flaws and fixing them one by one. From the brightness to the gray scale, and finally the colors.
Next Kane set his sights on the DVD player, because a TV is only as good as the devices that feed it with images. A calibrator, Kane explained, adjusts not only the TV, but also everything hooked into the TV. Gefen, for example, has a PC and a DVD player.
Gefen popped "Finding Nemo" into the DVD player. While others in the room were quickly drawn into the story of the little clownfish, Kane was driven to distraction by the grays on the screen.
"The gray scale is messy," Kane declared. "It's blurry. The lines are not clear." To demonstrate, he rewound to the title screen. Sure enough, the movie logo had a barely detectable fuzz around the edges of the word "Nemo."
Kane asked the brand of the DVD player.
"It's a Denon," Gefen answered.
"A 3910?" Kane ventured, guessing correctly at the model number. "It probably needs new software. Let's see."
Sure enough, Kane found out that the software was several versions out of date.
"Don't worry. I've got the latest update back at my office," Kane reassured Gefen.
They popped in a DVD of "The Matrix."
Gefen beamed at his TV.
"I think it's much better," Gefen said. "You can really see the difference in a dark scene. Before some of the faces were shaded. After the adjustment, you could see the entire face."
Still, Kane saw problems in the irregular colors on the dark walls in one scene at the beginning of the movie. He shook his head and promised to return with updated software.
Calibrators like Kane are trained to pay attention to conditions outside the set, such as the type of lighting in a room, that can affect the way a TV picture looks.
"Tungsten lights tend to be yellowish," said Fairchild of the Rochester Institute of Technology. "So you have to adjust the white to be a little yellower so the two will neutralize each other. Otherwise, the picture will look bluish."
Then there is the tendency among manufacturers to set their TVs at their maximum brightness, so that their products grab more attention in a crowded retail show floor with bright fluorescent lights.
"Typically, a TV is set up to look good in stores," Fairchild said. "At home, that same set just looks too saturated, too bright and unnatural."
"Not everyone gets the same quality out of the same TV set," Silver said. "If you paid thousands of dollars for that set, you want to optimize what you paid for. And that requires a professional person who can set it up so all you have to do is go home and press `play.' We help you get to the next level of image quality."

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Topic - Display calibration - rico 07:05:46 03/20/05 (0)

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