With “The Flash” (Warner Bros. Discovery) taking in a promising $9.7 million in Thursday previews (hoping to reach $70 million) while “Elemental” (Disney) grossed only $2.4 million, this weekend is perhaps the summer’s most critical for two of the brands that define franchise filmmaking.

However compelling those results might be, we’re already distracted by the upcoming drama of July 21, opening date for both “Oppenheimer” (Universal) and “Barbie” (WBD) — and the battleground for ongoing Imax screening of “Mission: Impossible — Dead Reckoning Part 1” (Paramount), which opens the week prior. As box-office battles go, this one will be hard to beat in 2023.

It’s too soon for audience tracking, but not to gauge industry expectations. There is a chance that the top three for the weekend of July 21 may be “Reckoning” #1, “Barbie” #2, and “Oppenheimer” #3 — but that would also be a misleading index. Here’s why.

“Reckoning,” which moved to a Wednesday opening to gain two more days of IMAX and other premium play, could be the biggest hit of the summer with a potential five-day opening of over $125 million. Franchise popularity and expectations aside, star Tom Cruise has enormous credibility after the success of “Top Gun: Maverick.”

That would suggest a second “Reckoning” weekend above $50 million at least — and less for “Oppenheimer” and “Barbie.” Industry sources suggest that “Barbie” has the edge and might ultimately be the bigger domestic success.

Neither is a franchise film. “Oppenheimer” is a biopic about a scientist, played by respected actor-not-yet-movie-star Cillian Murphy. Its real star is director Christopher Nolan, and its appeal includes literally how much bang the director can get for $100 million bucks (along with potentially stellar critical reaction).

“Barbie” is a comedy with primarily female appeal, with interest intense primarily from older and non-minority women. Director Greta Gerwig is two for two with “Lady Bird” and “Little Women,” neither of which were a guaranteed success. Margot Robbie and Ryan Gosling in the leads gives it greater star appeal than “Oppenheimer.”

Each cost around $100 million. (“Reckoning” is reportedly close to $300 million.) Unlike “Reckoning,” these films will rely less on a huge opening; more important is initial reaction that generates word of mouth and sustains several weeks of impressive theatrical play.

Driving Cruise’s drive to hold over IMAX screens is “Reckoning” needs multiple weeks of blockbuster performance to turn a profit. Without “Oppenheimer,” that would be a no-brainer… but Universal dated “Oppenheimer” when it announced the production in October 2020 and shooting with IMAX cameras guaranteed it would be an IMAX priority.

Previous “Mission: Impossible” films opened in late summer and did well with late-summer openings, but with “Oppenheimer” locking up three weeks of IMAX screens, the placement may have been the best possible. Cruise’s intelligence is key to his longevity, but if he hoped last minute to shift this, that was not based on realism-based thinking.

The IMAX advantage for “Oppenheimer” is a mixed blessing. It promises you must see it on the biggest possible screen to experience its full impact, but the limited number of premium-format screens are further constricted by the film’s three-hour run time. That will hurt its initial weekend gross even if many premium screens sell out all weekend.

It would comfort Cruise if “Reckoning” took the #1 spot in its second weekend, but that is secondary to more important factors facing all three films: initial grosses, how they perform over multiple weeks, overseas grosses, and their relative budgets. Horse races are entertaining, but the ranking only provides bragging rights.