The word 'mutuality' comes across now as a rather dated concept. It's a term which, for those of a certain age, will conjure up images of bicycles on cobbled streets, ration books and powdered eggs. The self-help mutual funds and building societies it once described have often been gobbled up by big banking concerns.

The notion that mutuality could have any role in a film industry entering a new digital age was a bit more laughable a couple of weeks ago before the free market states of Western Europe and the US began to put the Trotskyite dream into action by taking over the commanding heights of the economy.

But the idea was raised at the Screen International digital-cinema conference last week on the back of a serious concern that threatens to break one of the relatively slender bonds that unites the entire film industry - a single standard that covers the biggest blockbuster to the tiniest of micro-budget work.

Since the early days of the business, all films were created equal in the sense they were made of the same basic physical stuff. The inequalities were a question of nurture not nature.

The shift to digital cinema was meant to turn celluloid into bits and bytes with the same basic single standard. Defining what makes a film a film may now force you down the odd syntactical rabbit-hole but it can still be done. But what does film mean when you lose the unity of standards'

That anxiety does not seem far-fetched when you look at the current D-cinema roll-out. The fear that is expressed more loudly by the day is that a very large number of cinemas might not be able to afford to make the switch. Hence the notion of some new form of mutuality to support the small independents.

Yet the issue goes beyond even the serious question of facing a return to the boarded-up high-street cinemas that were among the more depressing aspects of the 1970s and 1980s.

The question people are too polite to ask at the moment is, 'So what'' The film business, after all, is a collection of highly competitive enterprises, not a crochet-your-own-wigwam collective love-in. A bit of Darwinian selection might not be such a bad thing, some argue on the quiet.

On the other side of the fence, a good many young people regard arthouse cinema as being as relevant as tea dances, whist drives or, well, mutuality.

They argue the natural place for film is anywhere it can be seen by audiences and the chances of most films being seen in a cinema are negligible. It is now common to meet young film-makers who don't see the cinema as a sensible or realistic home for their work.

It is true there is no inherent reason why film should be a single standard. The audiences for arthouse and specialist film are often a small subsection of the wider film market, which is being promised spectacular new experiences in D-cinema.

But cinema as a whole will suffer if it allows digital change to result in a gaping divide between grand spectacle and specialist intimacy. Commercially, film is always looking for the alchemist's magic formula but the strength of the medium is its ability to take you to unexpected places.

We may not have tested the full limits of the franchise yet but everyone has a boredom threshold and cinema's strength is its ability to surprise. If the roots are not watered, the most garish of blooms will wilt.

We will see movement on digital cinema installations across the world over the next few years - the studios have invested too much to let it drop. Schemes that work for most reasonably sized chains around the world will be signed.

For the rest, the industry and those that make claims to support it as an important part of the culture have to think very carefully before taking away a small but vital pillar of what the word 'film' actually means.

Mutuality and self-interest do not have to be mutually exclusive.