3D on TV

Channel 4 is currently having a '3D' week, consisting of two documentaries, a magic show, and three fairly bad films. It's not the first time they've demonstrated 3D television - some twenty-five years ago they broadcast the film Fort Ti in 3D using the red/green glasses method. The result wasn't terribly convincing.

I've been interested in 3D for many years; I saw the 3D films at the Telekinema at the Festival of Britain in 1951, and I've seen several of the famous Hollywood 3D films of the 1950s, including Kiss Me, Kate and House of Wax as well as a couple of modern 3D films at the IMAX cinema; so I was interested to see what sort of a fist Channel 4 would make of it this time round.

The method used in the films I mentioned above uses Polaroid glasses to separate the left and right images. This isn't possible on television, so it's back to coloured glasses. This time, in an attempt to maintain colour images, the glasses are amber (left) and a darkish blue. The theory seems to be that the colour is picked up in the left eye, and the right eye - which sees a darker image with little colour variation - adds the 3D effect.

It sort-of works, but not well. I have a particular difficulty in that my left eye is weak, so that my brain is used to taking most of the information from the right eye. As a result I saw a darkish blue range of colours, and found the fact that the left eye was brighter disturbing. However the 3D effect worked reasonably well. I tried turning the glasses round the other way: this gave me a better (though far from perfect) sense of the colour, but of course scrambled the 3D information.

Most of the 3D material in the documentary I watched was shot during the 1953 coronation procession, though the completed film was never released. There was also some 3D film of the young Queen boarding a boat for a journey on the Thames. The 3D was very effective in shots where there were people close to the camera, or even in the longer shots where there were people (some of them having climbed up lamp-posts) in the foreground.

There was also some modern material of Buckingham Palace and a recent garden party in its grounds; again, long shots were not very effective but some of the closer ones worked well. There was always a tendency for ghost images to appear on each side of an object, caused by breakthrough of the other eye's image - the colour filtering is never going to be perfect, and of course every television has a slightly different colour balance.

Another difficulty is that when setting up projected 3D the distant images must be two-and-a-half inches apart, no more - the average distance between eyes: if they are further apart the eyes are being asked to diverge, which is impossible and causes double images and eyestrain. This has to be set up for each individual projection; but of course on TV this can't be done. The distant images on my 40 inch screen were about an inch apart, so I imagine they aimed for two-and-a-half on the biggest available screens. Of course on a smaller TV the result will be to make everything appear closer and smaller.

It was an interesting experiment, and didn't give me as much of a headache as I feared it might (though I would be hesitant to watch a feature film this way); but it's not the future of 3D television - the results aren't nearly good enough for that and the whole system is inherently flawed. New processes are under development, but they will involve expensive new sets and dedicated transmissions: so don't expect it any time soon.

Posted: Wed - November 18, 2009 at 09:28 AM by Roger Wilmut          



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Published On: Mar 11, 2016 05:00 PM