If The X Factor final isn't your cup of tea this saturday, on BBC2 is an episode of Dads Army "Room At The Bottom" being seen in colour for the first time in forty years, after being restored using a new technique called Colour Recovery.

The Beeb, in its mad dash to annihilate its own heritage in the sixties and seventies, only kept copies of a lot if its shows originally broadcast in colour on black and white film to sell abroad.

The BBC press release takes up the story:

"James Insell, Preservation Specialist for the BBC Archive, found that many recordings had been created without the colour sub-carrier having been filtered out, and that the colour information was still embedded in the film as a pattern of fine dots – or "chroma dots". He speculated that it may be possible to extract and decode the dot pattern in order to retrieve the original colours

"Being able to restore such BBC classics as Dad's Army, for example, is such a great opportunity for us. It's amazing to think that, 40 years ago, no colour copies were ever kept of such iconic BBC shows.

"Finding that the colour information had been preserved, and now having a technology available to recover and reapply it, brings great potential for breathing life back into certain programmes."
http://www.bbc.co.uk/pressoffice/pressreleases/stories/2008/12_december/...

Amongst those programmes is editions of Top of The Pops. In fact the first test the group did was this previously black and white clip of Jimmy Saville introducing the mighty Blodwyn Pig

http://colour-recovery.wikispaces.com/