Apple on Monday was named in a federal class-action lawsuit that claims the computer maker deceptively marketed its new 20-inch iMac by grossly inflating the capabilities of its monitor.

The law firm Kabateck Brown Kellner LLP filed the suit in U.S. District Court in San Jose, Calif. The lawyers claim that Apple deceived consumers by concealing the fact that the new 20-inch iMac monitors are inferior to previous generations and the new 24-inch iMac.

In addition, the 20-inch monitors are incapable of displaying "millions of colors," as claimed by Apple, the law firm said. In fact, the monitors are only capable of showing 262,144 colors.

"Apple is duping its customers into thinking they're buying 'new and improved' when in fact they're getting stuck with 'new and inferior,' " Brian Kabateck, managing partner at Kabateck Brown Kellner, said in a statement. "Beneath Apple's 'good guy' image is a corporation that takes advantage of its customers. Our goal is to help those customers who were deceived and make sure Apple tells the truth in the future."

Apple declined comment. "We don't comment on pending litigation," a spokeswoman said.

While Apple describes the 24-inch and 20-inch iMac LCD screens as though they are interchangeable, they are actually of "radically different technology," the law firm said. The 20-inch iMac features the least-expensive technology for liquid-crystal displays, which translates into a narrower viewing angle, less color depth, and less color accuracy. In addition, the screen is more susceptible to washout across the display.

In describing Apple's alleged deception, the law firm pointed to the company's Web site, which tells consumers, "No matter what you like to do on your computer -- watch movies, edit photos, play games, even just view a screen saver -- it's going to look stunning on an iMac." The statement, according to the lawyers, is inaccurate because the inferior iMac screen is ill suited to edit photographs because of its limited color capabilities and the "distorting effect of the color simulation process."

"Apple is squeezing more profits for itself by using cheap screens and its customers are unwittingly paying the price," Kabateck said.

The lawsuit was at least the fourth filed against Apple this month. New York-based Klausner Technology filed a patent-infringement lawsuit against Apple and AT&T, claiming the companies violated its 1994 patent for technology that enables users to selectively retrieve voice messages via the iPhone's in-box. The suit was a revision of a suit filed in December.

Earlier in the month, Mirror Worlds, which sold desktop search and organization software in the early 1990s, filed a separate patent-infringement suit against Apple. ZapMedia Services filed its own lawsuit claiming Apple's iTunes online store and iPod portable media players infringed on its patents.