“Spider-Man 3” isn’t just the highest profile premiere in this year’s Tribeca Film Festival, it’s the unofficial standard bearer for the 2007 summer blockbuster season. The film is not running in competition at Tribeca. Executives and shareholders at Sony/Columbia have their eyes on a far bigger prize. At stake is the top slot in a summer crowded with other bluechip franchise films.

Breathlessly hyped summer openings include the third “Pirates of the Caribbean” movie, “Ocean’s 13,” “Live Free or Die Harder,” “Shrek 3,” “The Bourne Ultimatum,” and the fifth “Harry Potter” picture. Add to those sequels films based on familiar television shows like “Transformers” and “The Simpsons Movie,” and it would seem in the high-stakes box-office horse race, originality has become something of a liability.

“It’s been that way for 20 years or more,” said Jim Healy, the assistant curator of film at the George Eastman House film archive in Rochester and programmer of Eastman House’s Dryden Theater. “In the summer of 1987, ‘Beverly Hills Cop II,’ ‘The Untouchables,’ and ‘Dragnet’ were all the hype.” Indeed, 1987’s box office champion was “Three Men and a Baby,” a remake of a 1985 French comedy.

A mongrel combination of drama, music, literature, journalism, and photography, cinema is an art form particularly friendly to adaptation and influence from other media. Edison Films’s promotional literature promised, in proto ripped-from-the headlines fashion, that “The Great Train Robbery,” Edwin S. Porter’s 1903 landmark of narrative filmmaking, “has been posed and acted in faithful duplication of the genuine ‘Hold Ups’ made famous by various outlaw bands in the far West, and only recently the East.” D.W. Griffith’s “The Birth of a Nation” was based on a stage play, as was “Casablanca.” Orson Welles’s “Citizen Kane” was loosely adapted from the life of William Randolph Hearst and strongly influenced by Preston Sturges’s script to 1933’s “The Power and the Glory.”

Eight of the last 10 Best Actor and Actress Oscars have gone to actors portraying real people. It’s as if any film that isn’t already branded with the name of a successful prior iteration or known personality has no chance of getting green-lit, let alone honored within the industry. Many of the films in this glut of contemporary adaptations of comic books, TV shows, and biographies of cultural icons have the banal, generic voice of a single sentence pitch (“Jamie Foxx becomes Ray Charles!”) stretched to breaking over a two-hour running time.

The turning point for Hollywood brand anxiety, Mr. Healy observes, was in 1980. “The number one film of the year was ‘Empire Strikes Back,'” he said. The same year the box office was ruled by a sequel, Michael Cimino’s auterist melt-down “Heaven’s Gate” (loosely based on the actual Johnson County Wyoming range war) forced United Artists to the brink of bankruptcy and an eventual sale. “It begins there with competing executives asking themselves, ‘How do we keep our studio from getting shut down like United Artists?'” Mr. Healy said.

In hindsight, writing a blank check for a high-budget Western revival whose sole marquee name was the film’s own writer and director seems like the height of boardroom folly. But what was more telling than what United Artists did wrong, was what United Artists had done right until then.

The cash that UA hemorrhaged on “Heaven’s Gate” came from the company’s successful sequel franchises. “‘James Bond,’ the ‘Pink Panther’ and ‘Rocky’ films were what really kept the studio afloat,” Mr. Healy said. For bottom-line savvy producers, the message was clear: Give the people what they already know, and assume that it’s what they want.

“As movies get progressively more expensive to make,” Mr. Healy said, “studios feel they have more to lose if a film concept doesn’t suggest a built-in audience. It’s a climate of fear. There has to be something producers can show to nervous board members that they’ll recognize.”

But emphasizing marketing consensus over personal vision carries its own subtler form of risk. “When there’s that many chefs in the kitchen worrying about what elements the film has to have to be a hit,” he said, “that’s the surest way to water something down so that it’s lame and nobody responds to it.”

There’s a cynical back-lot adage that sums up a filmmaker’s responsibility to his audience thusly: “Tell them what you’re going to say, say it, then tell them what you just said.” At their worst, franchise filmmaking and off-the-rack adaptations and biopics represent the most dulling form of that risk-free repetition. Popcorn entertainment is still storytelling, and a story calls for more than just a familiar spectacle or an impersonation.

The peak moment of revelation in 1999’s “The Sixth Sense” forces the viewer back though the rest of the film to re-examine everything that has come before. Writer and director M. Night Shyamalan even provides a montage of key details to facilitate that process for viewers with poor memories. Darth Vader’s climactic declaration of fatherhood in “The Empire Strikes Back” forces the audience to reassess two whole films’ worth of events in order to emotionally validate Vader’s confession. As out of the blue as Luke and Darth’s newly clarified genealogy may have seemed in the moment, it made sense in light of what had come before. Think of it as being surprised by what you already know.

But the third installment in the “Star Wars” franchise was the weakest of the original trio, and sadly the most influential. When “Return of the Jedi” ended with a familiar explosion and victory, it felt, in plot and tone, as if it were merely a remake of the first film instead of a culmination of the first and second. Increasingly, film franchises, remakes, and adaptations don’t surprise with you with what you already know. Like “Return of the Jedi,” they merely regift you with something you already own — a story told better and more vividly once before.

Thus far, each “Spider-man” film has improved on the last. Sam Raimi’s gift for pulpy visual dynamism has become less encumbered with dubious computer graphic technology. The brilliantly staged and edited operating room massacre in “Spider-man 2” succeeded on the strength of old-school filmmaking acumen, not newfangled computer assistance. Key screenwriter Alvin Sargent and cast members Tobey Maguire and Kirsten Dunst have gone to considerable efforts to preserve an engaging emotional life and compelling stakes for Peter Parker and company. Of J. K. Simmons’s performances as Daily Bugle editor J. Jonah Jameson, I have nothing but worshipful, grateful praise.

But even as the lights dim at the premiere of “Spider-man 3” next Monday at Tribeca (May 4 around the country), for myself and other sequel-battered members of the audience, the prevailing sentiment is less likely to be “I hope this is good,” than “I hope they haven’t ruined it.”