Moving on

TV manufacturers have, for a while now, been advertising their HD televisions with the promise that they will make the "viewing experience more intense". Apparently there's a problem with lesser TVs whereby "at explosive speed" (a tennis match for example) "the action can become blurred and the detail missed". But they have come to the rescue because "motion clarity matters".

I'm pretty sure it's been asked before but I'll ask it again - what is the point of HDTV? I mean, how much detail do we actually need in a moving image? After all, moving images rely on our missing the spaces between each frame for the illusion to work. It's not about clarity, otherwise stunt doubles would never convince and Wallace and Gromit would painfully jerk their way through all their adventures.

In life we could, if we wanted, trace the flight of a swan or the arc of a cricket ball sailing to the boundary, but a bullet or an explosively served tennis ball could never be followed that way.

It is a nice irony that the urge of the early photographers to refine their technology so that it could stop life in its tracks was essential for the invention of the movies. The chemistry of photographic plates was improved so that they could be sensitive enough to record an image with just a fraction of a second of exposure. Combustible powders and primitive electronics were used to make workable flash systems that could compensate for dull light or illuminate pitch darkness. By the time Edweard Muybridge - often regarded, though not quite accurately, as the inventor of the movies - started getting curious about exactly what happens to a horse's legs when it's in full gallop, he had all the tools he needed to find out.

Muybridge produced his masterworks The Human Figure in Motion and Animals in Motion precisely to reveal details that cannot be seen in the flux of life. He approached the problem by setting up an elaborate test centre in California where he could break down a fluid movement such as the beat of a bird's wing or the leap of an athlete into some of its individual components by firing off a series of sequential photos.

It was a logical step for him then to try and recreate the movement he had fragmented in this way by stitching the images back together taking advantage of a toy that had been known since the 1830s. Muybridge's Zoopraxiscope, like the toy, relied on a phenomenom known as the persistence of vision. This is the retention by the brain of a kind of ghost image of quickly seen things that can be exploited to give an illusion of seamless motion by presenting a rapid sequence of images.

From their adverts, you'd think the TV manufacturers are trying to achieve an experience which does away with the gaps and the ghost images, leaving the viewer with nothing at all to do and making the smoke and mirrors dance of the TV into an exact equivalent of real experience.