Have you ever held your hand up in front of the TV screen and waved it from side to side? If you have, you will have noticed a kind of stroboscopic effect due to the interlacing of lines as the picture is built up (I'm talking old technology here). Keep that thought in mind. This is entirely tangential to the thread, but it sure caused this recollection to pop back into my mind with a small fanfare.
Originally Posted by Sirius Glass
Many years ago, when I was what's called a mature student at university, we lived very frugally, and had an old black & white TV set. The British among us may remember that old 'new technology' programme the BBC used to broadcast, called 'Tomorrow's World'. I was watching it one evening when one item on it caught my attention, introduced as a new cheap way of bringing colour images to monochrome TV sets with no modification, due to an effect that had been discovered, to do with strobes at different frequencies causing different colour responses to be stimulated in the cells in the human retina. The idea, the programme said, was that some limited colour effect could be produced by 'strobing' the broadcast image at different frequencies in different parts of the image, or some such. The design engineers were nowhere near ready for broadcast, but it was hoped to demonstrate the effect during the studio transmission of this edition, and have viewers respond to say what colours they were able to see in the stroboscopically enhanced image. The presenter continued by saying that in order to simulated the effect of strobing, the viewer simply had to make use of the known effect you get from interlacing, as I've mentioned earlier. All the viewer need do for the purposes of this test was to sit close to his monochrome set (the test was pointless for viewers with colour sets, it said), and when the test image appeared on screen, hold up an outstretched hand with the fingers straight and far apart, and move the hand from side to side in front of your eyes. Then, with luck, colour patches would appear in the test image.
Excited by the experiment, I sat cross-legged in front of our little monochrome set. The test image then appeared, and I held up my hand in front of my face, waving it from side to side and peering through the shadowy strobes of the fingers, anxiously looking for flashes of retinally stimulated colour.
As I sat there on the carpet twelve inches from the TV screen, waving my hands in front of my eyes, I slowly began to realise that the date was the 1st of April.