When, in the 1950s, television became widespread and began to take a serious chunk of the audience away from cinemas, the movies fought back in a number of ways. Gimmicks were rife (hello, William Castle). Colour became standard. Widescreen arrived. But other than colour and widescreen, every other innovation turned out to be a brief novelty, never to be seen again. There was once exception, a gimmick that was more popular than most, never became a standard, but refuses to die, resurfacing again and again after periods of dormancy, and that’s 3-D.

Over fifty years after Arch Obler (ironically, the king of radio suspense) unleashed Bwana Devil, there are signs that 3-D might finally be achieving a somewhat more stable position in theatres. It’s a long way from being a mainstream standard, but it has found a niche. Saunter down to your local IMAX and check out the offerings. Most of them will be in 3-D, and that includes blockbuster films (though in their case, the extra dimension turns up only in selected scenes). In IMAX, 3-D has finally lived up to its potential. Gone are the awkward red-and-blue-lensed cardboard glasses. In their place are gigantic plastic units not unlike goggles, that fit very comfortably over the viewer’s own glasses. Gone, too, is the headache-inducing effect of old-school 3-D. The current release Sea Monsters: A Prehistoric Adventure deploys 3-D as we always imagined it might be. The effect absolutely convincing, and absolutely immersive.