Hollywood's faith in the power of 3D movies to deliver a bright future of packed cinemas and spectacle-wearing audiences has been jolted by the box ofifce figures that show the high-tech format may already be floundering.
Seven months ago James Cameron's science fiction epic "Avatar" burst onto the screen in three dimensions, taking in $2.7 billion and becoming the highest grossing film of all time.
Studio executives in America compared the breakthrough to the development of first "talkies" almost a century ago, and fell over one another in the stampede to produce more such films.
But now, with the tally of major films released in the new format expected to reach 22 by the end of the year - with up to $7.50 extra being charged per ticket - there are signs that 3D may not after all be the panacea for falling ticket sales, telegraph.co.uk reports.
The proportion of cinema goers who opt to see new films in their 3D versions has fallen steadily over recent months, with more opting instead to watch them in the traditional and cheaper formats.
When "Avatar" came out in December, 71 percent of Americans who went to see it on the opening weekend - often the peak moment for a new release - opted for a cinema showing the 3D version.
In March, when the animated fantasy "How to Train Your Dragon" was released, 68 percent of the audience chose to see the film that way.
But by May that figure for "Shrek Forever After" was down to 61 percent. At the beginning of this month only 56 percent saw "The Last Airbender" in 3D, and a week later the proportion fell even lower, to 45 percent, for the newly-released animation "Despicable Me".
The figures have provoked an anxious debate in the industry, which had previously hatched plans to convert popular films on its backlist - everything from the "Star Wars" trilogy, to "Harry Potter", to the college pranks of Jackass - into the cinematic style du jour.
Studios are working on at least 24 brand new films in the expensive format for release next year. Now some fear that the "3D bubble" has already burst.
Critics say part of the problem may be the technology itself. While "Avatar" was specifically made in the new format, studios have hurriedly converted films that were originally made for two dimensions.
The process can cost up to $100,000 per minute of film but can be done in a matter of weeks, allowing for a quick release. However, a lot of the time it simply doesn't work and delivers murky pictures.
After seeing director M. Night Shyamalan's summer blockbuster "The Last Airbender", starring British actor Dev Patel, American film critic Roger Ebert said it "looked like it was filmed with a dirty sheet over the lens".
He said Hollywood's current infatuation with 3D was just an excuse to add surcharges to already expensive cinema tickets.
"Clash of the Titans", which was also converted and released in April, received similar criticism and was accused of actually putting audiences off the new visual effects.
Hollywood mogul Jeffrey Katzenberg, who was not involved with the film, called it a "cheeseball conversion" and suggested it was helping to "kill that goose that is delivering us golden eggs".
He said: "We're still at the beginning of this and not all 3D is equal, and consumers are beginning to realise this. There have been lesser 3D movies released and there's already been a backlash against it."
Christopher Nolan, the British-born director of "The Dark Knight" and "Inception", refused to use the new technology in his latest film because he found the dimness "extremely alienating".
But die-hard cheerleaders in Hollywood suggest the apparent migration of audiences back to traditional flat images is illusory.
While "Avatar" faced no competition when it came out there is now a flood of 3D releases and not enough screens equipped to show them. So far only about 5,000 screens in the US have been converted and 35,000 have not.
Studio insiders also point to the fact that only 28 percent of the cinemas showing "Clash of the Titans" on its opening weekend were 3D, yet accounted for 52 percent of its revenues.
They argue the proportion of tickets sold also depends on the subject matter of the film. The fantasy adventure "Alice In Wonderland", starring Johnny Depp, had the sixth biggest opening weekend of all time in March, grossing $116 million two thirds of which came from 3D screenings.
However, some of those who know the film industry best are convinced the latest trend will go the same way as the 3D fads of the 1950s and 1980s.
"3D is a waste of a perfectly good dimension and Hollywood's current crazy stampede toward it is suicidal," said Ebert. "It adds nothing essential to the movie-going experience. For some, it is an annoying distraction. For others, it creates nausea and headaches."
