The nitrate films which the BFI plans to screen are a form of social history, says David Gritten…

It’s the misfortune of film as an enduring medium that, for more than half a century, movies were shot on nitrate stock – the most fragile and flammable of materials.

Its unstable qualities are referenced heavily in two popular films: A long, memorable scene in Quentin Tarantino’s Ingluorious Basterds features a pile of nitrate stock being set alight in a locked cinema, consigning the audience of top-ranking Nazis to a terrible, fiery fate. In Giuseppe Tornatore’s nostalgic Cinema Paradiso, a blaze caused by combustible nitrate destroys a village movie house and blinds its projectionist.
It has its advantages, though: black and white films on nitrate stock have a lustrous quality – thanks to its high silver content. And the colours of ‘original dye transfer’ Technicolor nitrate prints can be breathtaking.

The British Film Institute plans to screen rarely seen nitrate films in July and August. To announce this programme, it organised a curious press event yesterday when fire marshals ignited nitrate stock outside its theatres on the South Bank.

It was enough to attract the attention of passers-by on Waterloo Bridge overhead, but it was all over rather swiftly. Still, the message was clear; this is material that demands great care and attention.

When it doesn’t actually catch fire, nitrate notoriously deteriorates, as a selection of film clips after the outdoor display proved. (BFI Southbank is the only public cinema with a licence to show nitrate films.)

Nitrate’s tendency to deterioration is a more serious problem than its combustibility. Film archives the world over have tried in vain to save old prints and negatives that discolour, show scratches, jump-cut alarmingly and often even crumble into dust.

Yet some of this stock represents the sole surviving print of thousands of titles. (Nitrate largely fell into disuse in the early 1950s.)

To restore them all would require a rescue mission of unrealistic proportions, but small victories are possible. The most widely acclaimed film restoration project in recent years has been that of Powell and Pressburger’s The Red Shoes, now looking dazzlingly lovely in Technicolor.

Martin Scorsese and the restoration team at the film and TV archive at the University of Los Angeles were rightly praised for their efforts in restoring The Red Shoes. But the BFI and the Rank Organisation optically copied the film from nitrate to safety acetates in the 1980s; their work formed the basis of the UCLA restoration project.

It’s an unsung but hugely valuable endeavour. We’re now firmly in a digital age, yet these old nitrate films offer unique glimpses into days gone by. In their way, they’re a form of social history, helping us recall that might otherwise be forgotten.(telegraph.co.uk)