It's understandable that you would want your favourite movie to be longer. Stanley Kubrick dropped 20 minutes from "2001: A Space Odyssey" after a week in release. Wouldn't you love to see that stuff? But now that films usually do turn up again in extended form, you have to wonder whether it's a double-edged sword.

It used to be that 'director's cuts' emerged after a film had been a huge hit and the director could force the studio to put back in scenes he'd been against taking out in the first place. The triumph of this art form is the extended "Aliens", which eclipsed the original release because the new stuff really does help. The action scenes deliver even after an hour of plot, there's added moments of warmth (and a first name) for Ripley, and a glimpse of Newt's colony before the aliens attacked. Set that against the extended cut of "Dances With Wolves". The original won a Best Picture Oscar, but the re-release just seemed... well, longer. There's a balance to be struck between adding unseen footage and maintaining the pace and shape the film had in the first place.

These days, it seems the theatrical release of a film is just a provisional version. In order to shift DVDs, films have to have additional scenes included. Considering how funny most of the jokes in "Scary Movie" weren't, can you imagine what the ones they edited out are like? A rare director with a sense of proportion is M Night Shyamalan. On the DVD releases of "The Sixth Sense" and "Unbreakable" he prefaces collections of cut scenes with the reasons why he dropped them. Sometimes, for the good of the film, excellent material has to go.

This line of thought is prompted by a couple of major restorations. Francis Ford Coppola's "Apocalypse Now" Redux, puts in about 50 minutes of hitherto legendary footage, and a US DVD edition of Robin Hardy's "The Wicker Man" which includes ten minutes of scenes trimmed against the film makers' wishes in 1973. In both cases, it's great to see sequences you've heard about for years, but it's hard to tell whether the new versions will replace the old in the affections.

As with the alleged 'director's cut' of "Blade Runner", the target audience for these releases is people who already know and love the original films. They know how the story is going to turn out. The narration on "Blade Runner" may be dreadful, but try following the story of the director's cut if you haven't already seen the compromised version and know what's going on.

On the DVD of "The Exorcist", producer-writer William Peter Blatty argued for the reinstatement of sequences dropped from the 'final' cut. In answer, director William Friedkin wryly cited the case of the painter Bonnard who was allegedly arrested in the Louvre wielding a brush to retouch his early work. The point is well made, and borne home when Blatty got his wish in "The Exorcist: The Version You've Never Seen". Most audiences tended to feel that the version we knew all along played better. The message would seem to be: if it's in the Louvre, let it go.

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