It is why the company?s Web site prominently features a ?match ?n? play court colorizer,? allowing users to experiment with variously hued combinations.

?There?s a lot of science in it,? Graham said.

For most of the sport?s history, outdoor tennis was played on the natural surfaces and colors of grass and clay. When technology allowed for surfaces like asphalt or carpet, they were predictably colored in the traditional greens or reds, as if to mask artificiality.

No more. Today?s top tours play their tournaments on a kaleidoscope of colors: purple at Miami and Doha, brick red of the European clay, pale green grass at Wimbledon (and, in the second week, swaths of beige dead grass and dirt), and deep blue on the North American hardcourts.

Around the world, at lesser-known tournaments, public parks and college campuses, all conceivable combinations of color are being laid down, gridded by white lines and sliced in half by a net.

Among the notable advances in tennis the last few decades, like graphite rackets and computerized line calls, the most drastic may be in the color of the courts. ?It?s just a little thing that can make a big difference,? said Gayle Bradshaw, the Association of Tennis Professionals? vice president for rules and competition.

Marketing is usually the impetus for changing the color of a court, a canvas potentially seen by millions on television. Tours and tournaments use color to help create instant recognition.

But choosing which colors to use is complex. More and more, the concern is about making it easier to track the optic-yellow ball that often travels more than 100 miles an hour ? for the players, the fans sitting courtside and the masses watching on television.

In 2000, the ATP started using purple for its Master Series events. In 2005, the United States Open changed the color of its green courts to blue. The Australian Open followed in 2008, eliminating the single-tone green to a two-tone blue: lighter on the court, darker surrounding it.

And now, amid much debate, the Madrid Open is pushing to change the color of its clay, from familiar red to a deep blue. That quest has found little support among players but will be seriously considered during tour meetings in a few weeks.

?I still also think it?s important to stay true to tradition,? the No. 3-ranked Roger Federer said. ?Keep the red clay, obviously, those kind of things. Grass doesn?t become orange, all those things. It just would be all strange.?

But tennis is keeping its options open. And the moves to purple and blue are not just coincidental commercialism.

?If you?re familiar at all with the Isaac Newton color wheel, you?d see that the purples and the blues are almost 180 degrees opposite of the yellows on the wheel,? said Graham, whose company has built courts for the United States Open and the Olympics, among other sites. ?So the greatest amount of contrast is created with the yellow and the blue or purple.?

It may seem a trivial point. But you are probably not broadcasting a tournament from, say, Roland Garros, where the contrast between the yellow ball and the red court is often muddled by the faded light of dusk or the cover of dark clouds and where the felt of those bright balls is quickly stained by the dust of crushed brick.

?The weakest tracking of a ball on a surface is the yellow against the red,? said Jamie Reynolds, who oversees ESPN?s tennis coverage as the vice president for event production. ?It?s the most challenging of the four majors.?

While the red clay presents its own challenges, the color wheel shows that the weakest contrast may be between green courts and a yellow ball ? which became standard in 1972 (and accepted at tradition-rich Wimbledon in 1986) for reasons of visual clarity, too. According to the color wheel, Wimbledon and other green-court tournaments may want to consider a different color ball. They are not.

In 2005, Arlen Kantarian, then the chief executive of the United States Tennis Association, spearheaded a change in the color of the courts for the United States Open and the hardcourt tournaments preceding it. The Open, which began as a grass-court tournament, had long been played on green hardcourts.

The U.S.T.A. was mostly interested in rebranding the Open and what became the U.S. Open Series. In consultation with DecoTurf, the U.S.T.A. seriously considered deep blue and bright red courts. In the end, red was axed because of concerns over how it would look when it faded. DecoTurf devised blue courts surrounded by a green out of bounds.

?This court should have been blue for the past 50 years,? Kantarian told The New York Times at Arthur Ashe Stadium in 2006. ?You look at tapes from even two years ago, and it looks like they?re in the 1940s.?

Jim Curley, the United States Open tournament director, said he noticed the difference while watching the Australian Open on television when it still had green courts.

?I couldn?t follow the ball,? Curley said.

In 2008, the Australian Open changed its all-green courts to a two-tone blue.