Transformers 2: Revenge Of The Fallen is about the battle between Decepticons and the Autobots. But the opening also represents an early skirmish in a fight that pits the No. 3 theater chain Cinemark up against Imax. Cinemark launched its own large-screen format, called Cinemark XD, in West Plano, Texas back in March. Already, films such as Monsters vs. Aliens and Star Trek appear to have done well there. Now Transformers 2 likely will be the biggest test of the format’s appeal vs Imax. And if enough ticket buyers are willing to fork over the additional $3 to see a film on XD’s 70-foot wide screens, then theater owners may decide to use it instead of scamming technology Imax Digital to offer audiences that “immersive experience”. Cinemark boasts that, unlike with Imax, it can offer any digital film in XD, including those in RealD 3-D. It also provides an alternative for theaters that can’t do business with Imax because of local exclusivity deals. Cinemark plans to have as many as 15 XD screens over the next few months.