Who needs a gimmick?

A novelty image isn't everything in rock'n'roll, says Steve Jelbert - but it certainly helps

If you haven't heard of the Trachtenburg Family Slideshow Players, prepare to be enlightened. Made up of a husband and wife team, Jason and Tina, and their daughter Rachel, this nuclear unit use found items, particularly discarded photographic slides, to suggest narratives that are then transformed into songs. Daddy and daughter perform, while Mom operates the projector. The blunt effect of seeing what is sung proves starkly effective, and bleakly funny at times.

If you haven't heard of the Trachtenburg Family Slideshow Players, prepare to be enlightened. Made up of a husband and wife team, Jason and Tina, and their daughter Rachel, this nuclear unit use found items, particularly discarded photographic slides, to suggest narratives that are then transformed into songs. Daddy and daughter perform, while Mom operates the projector. The blunt effect of seeing what is sung proves starkly effective, and bleakly funny at times.

For instance "Mountain Trip To Japan 1959" is accompanied by a set of holiday snaps padded out with a couple of non-sequiturs obviously taken to finish off the original roll of film. Elsewhere they take outdated, optimistic company reports from a pre-Powerpoint age and turn them into wistful history. Their first British release, Vintage Slide Collections from Seattle, Vol. 1 demonstrates the power of fairly recent slideshow software when slipped into a computer's disc drive, although the sticker on the sleeve proudly boasting that "they turn strangers' old slide collections into mini rock operas" probably exaggerates a tad.

This curious show can be seen in London next month, then soon at its natural home, this summer's Edinburgh Fringe, and after that tempting description you're doubtless salivating at the prospect. Yet the Trachtenburgs must be applauded for cunningly generating "added value", that tenuous concept that separates them from all the other struggling family acts out there.

Artists, even niche artists, have to offer more in these tricky times and even this small gimmick distinguishes them. No one adds value like a proper rock band. Kiss made their millions by selling records such as Love Gun to pre-pubescents who cracked open the packaging to discover their very own cardboard "love gun", which they could then wave in the faces of their concerned parents.

AC/DC's Bonfire, a box set that paid tribute to the work of their original singer Ronald "Bon" Scott, actually included a bottle opener. Given his death following a night of alcoholic overindulgence, some might view that as a touch too much.

Why not try leaving an enduring memory through your stage show? In 1997, Metallica went to the trouble of simulating an equipment failure every night, with "collapsing" lighting towers that appeared to flatten a techie who would require medical attention. "Spontaneously" reconvening in a dusty corner of the stage, the band would plug in to a minimal rig, just like the old days back in the garage, and gradually get back up to full volume.

Further down the food chain, artists such as the power duo Lightning Bolt (bass and drums only, microphone taped in place to the face, thank you) simply refuse to take the stage, preferring to set up on the plains below where their eager audience can surround them.

Far more absurd is the reported approach of their labelmates, the wetly named, though seriously rowdy Friends Forever, who don't even get out of their van when they arrive at the venue. They don't need to, as it's fully set up for live performance. They not only have a sound system, but even a lighting rig. And possibly agoraphobia. Just leave a mark on the punters' collective memory.

The Polyphonic Spree, back with a new album next month, are known for having a ludicrously huge line-up. For a rock band, that is - if they were a touring production of Cats no one would comment. The Hidden Cameras, Toronto's purveyors of "gay church music", liven up their stage act with a few masked "go go boys", just in case you spot that all their songs are built around the same couple of chords. The White Stripes' minimal set-up might be a commonplace now, but was unusual four years ago. (Touring for months on end with one's former spouse remains rare though.) And though the Flaming Lips might once have released a record on four CDs, which were meant to played simultaneously on four different machines, it's the onstage extras in animal suits people remember.

Some important folk claim to have sweated alongside the band inside those get-ups, including half of Britain's music hacks, some competition winners and Zoë Ball. The Lips' frontman, Wayne Coyne, has also taken up the tried and tested "rolling around on top of the moshpit inside a huge ball" trick, previously associated with the patron saint of added value, Peter Gabriel.

In the Seventies Gabriel was better known for his interesting range of stagewear ("A flower!" he sang, while dressed as one) than his band's dogged prog rock. The techno-savvy Gabriel has consistently attempted to add extra features to his later work - lighting rigs that appeared to attack him, performances on an "upside-down stage", even collaborations with the likes of the theatre director Robert LePage and man's closest relative, the bonobo, or pygmy chimpanzee.

The ever drabulous Elton John recently sought to liven up his image by employing the photographer David LaChapelle, known for his lurid style, to design a stage set for his Las Vegas residency. As a distraction from the sight of a peculiar haired fellow seated at a piano, it succeeded, reviving memories of the lunatic Busby Berkeley-esque extravaganzas that made Elton synonymous with Seventies excess. Even Madonna is on tour, as usual distracting attention from her relatively weedy voice with the very definition of subtracted value, a cover of John Lennon's "Imagine".

Of course some people don't need a gimmick at all. They are their art, at all times, and as long as you don't have to live with them, or work with them, or have personal contact with them ever, that's great. It's hard to imagine, say, Morrissey kicking back and watching the racing while Radio 1 plays in the background, or Van Morrison picking up the grandchildren from playgroup. (Come to think of it, it's horribly easy to imagine Morrison doing that, but only as a minibus driver employed by the council.)

After all these years they really are their own image, much like a long-running soap actor. Relative dullards can be just as true to themselves too. Hence the huge success of the Coldplays and Travises and Keanes, passing turns whose gimmick is the lack of anything but the music. If that doesn't grab you, bad luck.

Strictly speaking, added value can work only once, when artists are on their way up and need to stand out from their contemporaries. Yet the boundaries between formats are becoming ever more blurred. The current "best of", Supergrass Is 10, offers a choice of the plain old CD or a two-disc DVD, including commentaries and the frankly terrifying "karaoke option". Ideally, we'd get basic commentaries on cut-price reissued CDs: Shaun Ryder, perhaps, admitting that he can't remember a single thing and telling a joke instead. (Sadly I suspect we'd just get musos mumbling about muso things instead.)

Yet music alone can sell in huge quantities. Namedropping OutKast's Speakerboxxx/The Love Below might be as obvious as referring to Bill Hicks and Johnny Cash, but this sprawling though satisfying double has sold millions. They do have a great image though, and from the highest to the lowest, it helps.