15/03/2013 12:25 GMT | Updated 15/05/2013 06:12 BST

As Great a Gatsby? The Challenge of Adaptation

So The Great Gatsby will headline this year's Cannes Film Festival. It is a statement billing - though of course no guarantee of any later critical touchdowns - which has not gone unnoticed on the film-anorak radar. It is a lofty promotion, rather like a thumbs-up from Roger Ebert or a hug from Oprah, which lends early torque to a media campaign (not to mention that of DiCaprio vs. the Oscar voting body - a Californian standoff which is playing well in the Redditgeist). In 2013, Jay Gatsby has found himself, once again, the beau of the ball.

Only the ball in question is not the flapper-dress dream of Fitzgerald's Long Island - it can only, by definition, amount to a cutting-room charade. Computerised, rasterised, and altogether Luhrmannised, it will ostensibly (I'm guided by its lavishly over-the-top trailer) knock back special effects like so many of Zelda's martinis. If the adaptation can only ever ghost the writer's vision, where is the value (mega-bucks aside) in filming the unfilmable?

Adaptations are the mac 'n' cheese of modern Hollywood. The marketing executive dangles a shiny bestseller before the film consumer like a matador's capote; powerless to resist its allure, he dives for knowing it's probably a mirage of brilliance - and that he won't even get to gore the guy behind it. The label of 'adapted screenplay', a tag which has brought both mirth and misery over the years, operates an open-door policy indeed. A derivation of any kind qualifies a film as an 'adaptation', with source material ranging from Penguin Classics to bootlegged short stories. Only a genuine 'spec screenplay' - the kind you associate with d-bags in Starbucks bashing away at their Macbooks and Frappuccinos - is fundamentally destined for the movies.

Shotgun marriages of prose and camera run into all kinds of impediments. A good novel and a good movie sit back-to-back, looking in opposite directions; the pleasure of reading comes from a trip into someone else's mind - we read the characters' thoughts as if they were our own. Film, on the other hand, is an outward observation, and the audience a peeping voyeur rather than a passenger in the subconscious. The only mind we are allowed to enter is that of the director - but of course in adapting the words of another, his hands are tied and his thoughts muffled.

Length is a seriously sticky wicket. Themes which are spun over hundreds of pages must be crunched, concertina-like, down to feature-length, racing through the big conceptual guns before audience bladders reach capacity. The bigger the novel, the longer the tightrope - Joe Wright is a notable wobbler, his blundering recitals frequently riding on the coat-tails (literally) of his costume department.

Theatrics, incidentally, are best delivered at a distance. Diction, projection, enunciation - these are circumstantial necessities of the stage, where facial writhings are important in relaying emotion up to the nosebleed seats. Play-adaptation comes a cropper where tensile tonsils remain in close-up, to be scaled to the squeamish dimensions of the screen (see 'Anne Hathaway, 2012'). The insularity of the stage tilts in favour of dialogue, and in adapting 'great' plays, the words which are so loyally preserved swamp scenes and leave no time for the camera - a prime example is A Streetcar Named Desire, its enduring approval balanced on the burly shoulders of Marlon Brando's Stanley, like so many bananas on an over-laden donkey.

The adaptive game is won and lost in pre-production. Selection of a trashy novel needn't result in a trashy film - The Shining was never Stephen King's finest hour, but it was visually-orientated and a loaded gun for a director with a taste for the macabre. Novellas and short stories, like A Clockwork Orange and Breakfast at Tiffany's, allow breathing room for the camera and often lean conveniently on imagery in lieu of long-developed themes. And in times of crisis, shoehorning in some superlative lead actors will mask any hitches of direction - think Julie Walters and Michael Caine in Educating Rita, or Daniel Day-Lewis in My Left Foot.

It is one of many transgressions of popular belief that leads cinema to be a receptacle for the re-runs of other media. (Parenthetically, a trade in reverse would be unthinkable; imagine the novelisation of The Tree of Life). The whipping boy of the household novel, it props up legacies and re-brands classics, selling its soul in the process. It is a cheerleader which has long outgrown its tube socks.

In any case, Leonardo DiGatsby is on his way to Cannes, and we await the post-match analyses which will likely drag us through to the next Oscars. Budgeted at $127 million, it comes with a ready-made irony on the excesses of the American Dream - which have become no less remarkable since Fitzgerald's 1920s. Baz Luhrmann's party is, nevertheless, the hottest invite in town.