Quark Inc. last month began shipping its long-awaited OS X-compatible version of its flagship QuarkXPress layout application.

The announcement detailing QuarkXPress 6’s release was made at Apple Computer Inc.’s Cupertino, Calif., headquarters, sending a signal to users that the two companies are now working hand-in-glove to support each other’s technologies.

QuarkXPress 6 is the last major application engineered to natively support Apple’s OS X operating system. Software developers have been rushing to engineer OS X-compatible apps since last summer, when Apple said machines sold after Jan. 1, 2003, would only boot into OS X as the startup operating system.

In late 2002, Apple slightly modified its stance, announcing it would allow certain models of its current product line to boot up OS 9 through June 2003.

Steve Jobs, Apple’s chief executive officer, called the release of QuarkXPress 6 “the most anticipated application of the year for our professional customers.”

“Quark has removed the last barrier for creative professionals to move to Mac OS X,” he said in a statement.

Newspaper production managers and designers have nervously watched to see how the drama would play out between Apple’s determination to support only OS X and Quark’s protracted development schedule of a native version of QuarkXPress. QuarkXPress 5, the most recent version, was released almost two years ago and the first public announcement by Quark regarding QuarkXPress 6 didn’t occur until this spring.

In the meantime, Quark’s arch-competitor, Adobe Systems Inc., rushed to craft an OS X-compatible version of InDesign in a bid to chip away at Quark’s dominant market position.

One newspaper publisher planning to adopt QuarkXPress 6 is HomeTown Newspapers in Livingston County, Mich. “As soon as it’s available we’ll upgrade several copies and begin testing,” said Clyde Peasley, production graphics manager, adding that it will take “several months” to make sure the software and related extensions mesh with the company’s Baseview and Miles33 editorial and advertising software.

Market watchers, meanwhile, said the release of QuarkXPress 6 changes the production landscape. “It makes the market very interesting,” said Dominick D’Acquisto, a Wisconsin-based independent analyst and consultant. “In one regard, for all the time it took Quark to release 6, the company has started to lose some market share to Adobe while people waited and wondered when it would ship.”

On the other hand, D’Acquisto said, since QuarkXPress 6 now natively supports the Unix-based OS X operating system, its performance, speed and stability could yield some compelling advantages to users examining whether to make the switch to OS X.

And Apple’s commitment to the new operating system isn’t the only motivation pushing newspapers to migrate, he said. Some newspapers are continuing to use older versions of QuarkXPress, particularly QuarkXPress 4, first released in 1997, because users didn’t see much value in adopting QuarkXPress 5. The combination of the new operating system plus features and capabilities built into QuarkXPress 6 may give the Denver-based software vendor a boost.