It was expected to be one of the biggest weekends ever at the domestic box office. Instead, the usual Sunday morning ritual of parsing spreadsheets and spinning the numbers was suspended out of respect for the victims of Friday’s tragic shooting rampage at a midnight screening of “The Dark Knight Rises” in Aurora, Colo.

In what biz veterans called an unprecedented show of solidarity, Warner Bros., the other major studios and box office aggregator Rentrak opted not to report weekend grosses on Sunday. Industry insiders said there was a collective understanding that Hollywood should not be beating its chest about boffo B.O. at a time when the nation is still reeling from the jolt of the massacre that left 12 moviegoers dead and more than 50 others wounded. President Obama traveled to Aurora on Sunday to meet with victims and their family members and local authorities.

For B.O. observers, the quiet on Sunday morning reinforced the enormity of the loss given that “TDKR” was one of the year’s most anticipated tentpoles. Amid nonstop media coverage of every aspect of the attack, bizzers spent the weekend coping with the fact that in the midst of the crucial summer B.O. season, a lone gunman in a matter of minutes may have done lasting damage to consumer perceptions about the sanctity and safety of the moviegoing experience.

Despite the horror visited upon Theater 9 in the Century Theaters complex in Aurora, moviegoers were not scared away from the plexes: Indications are that “TDKR” collected north of $160 million starting with its midnight Friday screenings.

Revised figures will be reported Monday, but if the estimates hold up, this would be the biggest 2D opening of a film ever — beating the $158 million bow for “The Dark Knight” in 2008 — and probably the third highest overall, behind those of “The Avengers” ($207 million) and “Harry Potter and the Deathly Hallows: Part 2” ($169 million).

“TDKR” was originally pegged to hit at around $175 million through Sunday. The film’s estimated $75 million Friday gross was only slightly less than expected. Bizzers estimate that “TDKR” fell 39% from Friday to Saturday, an expected drop given the film’s $30.6 million midnight gross. By comparison, 2008’s “The Dark Knight” fell 30% from Friday to Saturday but had a smaller midnight benchmark at $18.4 million.

Most showtimes for “TDKR” were sold out, and for moviegoers who chose not to see the pic this weekend, several chains, including AMC and Pacific Theaters, offered full refunds.

Theater owners acknowledged their security concerns at plexes nationwide. Some exhibs like Regal restricted costumes or masks, while others, including AMC, banned such attire altogether. Though latenight and early-morning screenings of “TDKR” went on as scheduled, exhibs had beefed-up security from local law enforcement.

Like their studio partners, exhibs also reflected the somber mood by downplaying the weekend’s glowing results. Never has there been such a nearly uniform decision to withhold official B.O. estimates on Sunday morning — not since the reporting of B.O. grosses became a routine process for studios in the early 1990s.

The fact that it happened this weekend — when the only thing more anticipated than “The Dark Knight Rises” itself was its weekend haul — reinforces the impact of the shootings at a multiplex on the industry’s collective psyche.

The Monday after JFK was shot, Daily Variety carried box office grosses (at a time when reporting B.O. wasn’t really organized, except for noteworthy results). And “Cleopatra,” for example, did pretty well: “In its 23rd sesh at the Pantages, ‘Cleopatra’ was sold out completely during both performances Saturday, while Friday night was off about 50 percent.”

On Sept. 17, 2011, the first weekend after the 9/11 terrorist attacks, Variety carried a report about Paramount’s baseball drama “Hardball” leading the weekend B.O. with $10.1 million.

“TDKR” helmer Christopher Nolan captured the sense of heartbreak that many industry insiders expressed over the weekend in his emotional statement on the shooting.

“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 said. “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. Nothing any of us can say could ever adequately express our feelings for the innocent victims of this appalling crime, but our thoughts are with them and their families.”