Big-screen purveyor Imax ( IMAX) got a lift from Superman Returns over the Independence Day holiday. The company, which in conjunction with Time Warner's ( TWX) Warner Brothers featured the film as part its Imax 3D Experience, said that Imax theaters contributed $6.83 million of the film's $108 million seven-day take. That represents a per-screen average of $89,804. Those tallies are records for Imax, which has increasingly benefited from partnering up with Warner Brothers and others on blockbuster releases. The film is currently being viewed on 76 Imax screens. It also opened on 11 Imax screens internationally and will launch on 24 more in coming weeks. Imax used its proprietary 2D to 3D conversion technology to convert some 20 minutes of Superman Returns. Despite its recent successes where big studio partnerships are concerned, investors eagerly await news of a possible sale. The company, which makes its living showing Hollywood blockbusters like Superman Returns in big-screen format and also by licensing out its large-screen theater technology around the world, said earlier this year it was looking at strategic alternatives, including a sale. It hired Allen & Co. to direct the process. Sources said in the spring that Imax is entertaining a second round of bids, but since then things have been quiet. Interested parties are said to include technology and entertainment companies both domestically and internationally. Warner Brothers has partnered with Imax frequently of late on films including Harry Potter, Batman Begins and The Polar Express. "We are thrilled with the initial success of Superman Returns in both conventional theatres and Imax theaters," said Warner Bros. Pictures domestic distribution President Dan Fellman, in a statement. "The special Imax 3D release has been well received by moviegoers across the country, and will continue to play to sell-out crowds." On Thursday, Imax shares dropped 10 cents to $8.73.