One of the worst mass shootings in US history wreaked havoc on the lives of those who live in Aurora, Colo., where a gunman killed 12 people early Friday morning at a multiplex theater. The murders are also expected to impact the movie going experience indefinitely.

Since news broke that James Holmes, a doctoral student in neuroscience, allegedly shot 70 people in a midnight screening of the popular Batman franchise, many theater chains issued statements changing their security policies. For example, AMC Theatres said face-concealing masks or fake weapons would not be allowed. Classic Cinemas, a chain in Northern Illinois, issued an open-ended ban on backpacks “or other large bags” as well as masks.

More changes are expected. The National Association of Theatre Owners, a trade group in Washington representing over 30,000 theater screens in the US, issued a statement Friday that its members “are working closely with local law enforcement agencies and reviewing security procedures.” Many national theater chains announced increased security personnel starting this weekend and said they were examining their policies for possible changes.

Colorado shooting: Picture emerges of chaotic scene, suspect James Holmes

Costumes are common sights in midnight showings, primarily for fantasy or science fiction fare involving film franchises that can stretch for years, allowing audiences to invest in characters and story lines on a more personal level.

“Midnight showings of these kinds of movies just enhance that sense of ritual and make it more of a bonding experience for people willing to make the extra effort to stand in line and stay up late,” says Rob Salkowitz, author of a just-released book called “Comic-Con and the Business of Pop Culture” and a professor at the University of Washington in Seattle. “We want to get together and hear these stories told and share our love of them. It’s really affirmative.”

The film industry also relies on the midnight showings to boost revenue on opening weekends, which is crucial in an era when it’s feeling the crunch from competing living room entertainment like cable television, streaming Internet movies and television shows, and video games. Midnight screenings are part of recent strategies like IMAX and 3-D technology meant to encourage the live experience in an era when so much is compelling audiences to stay home.

Thelma Adams, a contributing editor at Yahoo! Movies in New York, says the potential fallout from the Colorado murders could harm attendance.

“If they start making going to the movies like going to the airport, it’s going to hurt theaters, no question about it. Theaters are at a point where they can’t make it less attractive to attend,” Ms. Adams says.

Increased security measures are inevitable now, just like they were in airports after the Sept. 11 terrorist attacks and reinforced security on college campuses following the massacre at Virginia Tech University, says Paul Levinson, a media expert at Fordham University in New York who predicts metal detectors will be installed in theaters in most major cities.

“Once the line crosses into something like this, the movie industry has to think of ways to make the public feel safe,” Mr. Levinson says.

Theater chains have an incentive to increase security because, unlike attending class or traveling, they know people can just as easily stay home. “You don’t have to go to the movies. It’s a completely optional experience. So the last thing the industry needs is people worried about going to the movies,” he says.

Just like the airline industry, the measures will most likely affect ticket prices, which have already risen 40 percent between 2001-11, according to data from the National Association of Theatre Owners.

“If [theater chains] have to start adding security, they’re not going to take that on without passing it onto us,” says Anthony Mora, a media consultant in Los Angeles.

“The Dark Knight Rises” is the third and potentially last chapter in the popular re-imagining of the Batman saga by director Christopher Nolan. Warner Bros. announced it would not release box office numbers throughout the weekend although Variety reported that the film earned $30.6 million from about 3,700 screens from the midnight screenings alone. Total box office through Sunday is predicted to end up close to $180 million, which will make it the most profitable opening weekend of all time after “The Avengers” earlier this summer.

Despite the windfall, Mr. Mora says that the studio will remain vulnerable in how it markets the film in the future because it is now “directly connected” to the massacre. “It’s not like [the killings] happened in a mall or near the theater. They happened in the theater when this movie was playing. You can’t separate them now,” he says.

Director Nolan issued a statement late Friday expressing “profound sorrow” for the victims and suggested the violence now corrupted the pleasure of going to the movies.

“I believe movies are one of the great American art forms and the shared experience of watching a story unfold on screen is an important and joyful pastime,” he wrote. “The movie theater is my home, and the idea that someone would violate that innocent and hopeful place in such an unbearably savage way is devastating to me.”

Mr. Salkowitz said films like “The Dark Knight Rises” are attractive because they invite an escape from real life violence.

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“One of the great things about the fantasy space in comics and movies is that they were exempt from that,” he says. “Anything that punctures the mystique – especially in such an appalling and horrifying way – does damage that is likely to extend far beyond the bottom line.”

Colorado shooting: Picture emerges of chaotic scene, suspect James Holmes