When you take a best-selling children's book and turn it into a movie, there is a good chance that its fans are going to have some strong opinions about it.
The first adaptation of Rick Riordan's five-book Percy Jackson series, the 2010 film Percy Jackson & The Olympians: The Lightning Thief, upset some fans because it was not entirely faithful to the novels, more than 20 million copies of which have sold worldwide.
Although it did well enough at the box office (US$226 million or S$290 million) to warrant a sequel - the newly released Percy Jackson: Sea Of Monsters - the new director in charge of the franchise felt more could be done to capture the spirit of the source material.
It helped that 40-year-old Thor Freudenthal, who took over from The Lightning Thief director Chris Columbus, the man behind the first two Harry Potter films, was an avid Riordan reader himself.
"I am always interested in fantasyadventure material, especially when it's grounded in realistic characters who, on the outside, don't look particularly special," he tells Life! at a press event in Beverly Hills recently.
"I flipped through the books and then Chris' film came out, which prompted me to read the rest, so I was a fan even before I did this."
The Berlin-born director was aware that the first film had caught some flak for deviating from the novels, which follow the adventures of Poseidon's half-human son Percy as he discovers his real identity and super-powers. And the books' fanbase is even bigger now because of the success of the first film.
So Freudenthal went into the project wanting to recapture more of the books' humour and lightness of touch.
"When I read the books, I found them funnier than I had expected. They are very humorous and quick-witted, and kind of sardonic and selfdeprecating, which also gives them a great pace.
"So the first thing I said to the studio was, 'Can we be very light on our feet, and have this movie have a spring in its step?' Because I think, especially in the first 20 to 30 minutes, you have to open up the audience and get them ready to invest in a character.
"And if you don't have the humour, I don't think the audience would be as invested in the outcome of the characters' fates in the second half."
Freudenthal, who directed the 2010 movie Diary Of A Wimpy Kid, based on the popular children's books by Jeff Kinney, wanted to set this apart from other films inspired by young-adult novels.
"The way I think Percy Jackson distinguishes itself from the mass of young-adult literature is that lightness of tone - that unique pairing of deep emotions and strong feelings for the main character and his relationships, and knowing when not to take itself too seriously, which I think is important for a movie like this."
The star of the films, 21-year-old Logan Lerman, believes that this tone did find its way onto the screen this time around and that fans of the book will be pleased with the results.
"I think fans are really going to like this movie because it's much more accurate in terms of the tone of the books," he says in a separate interview. "In the first movie, we kind of did our own thing and took a lot of creative liberties in terms of the story. This is much closer to what the book feels like."
Still, loyal readers should not expect everything to be the same, either in terms of the plot or the characters, who are still a little older than they are in the novels - a decision made by Colombus, who realised it would be much easier working with actors who were not quite so young.
And, of course, turning long books with a complicated mythology and backstory into a film of less than two hours involves some ruthless editing.
Freudenthal says: "When you go about adapting a book that's as big as The Sea Of Monsters, with hundreds of pages of story that takes place over a long stretch of time, you have to make certain sacrifices.
"What you have to do, in a movie which is 90-something minutes long, is pick a basic strand of story and make everything be in service to that story. We had to weed out anything that didn't immediately have to do with the main quest. So it's very streamlined as a movie."
Any worries he might have had that he missed out something crucial, however, were laid to rest by a young fan of the books.
"My fiancee has a niece who is 11 years old, and after we made the movie, she made her own video describing the Sea Of Monsters plot in five minutes.
"And I was happy to realise that everything in it was mentioned in the movie. It was like, phew, okay."
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