Next Saturday is a special Dad's Army night on BBC Two. Most of the programmes on the night are things that have been on before, including the Missing Presumed Wiped documentary and the Comedy Connections episode.
However, there is something rather special on the night. There will be a showing of the episode Room at the Bottom in colour, for the first time since 1970. For many years, the episode only existed in black-and-white.
A colour recording was made, then it was re-recorded in black-and-white from the colour version, which was then wiped. A new technique has been developed which allows it to be restored to its original colour. This is because black and white film frames actually contain the original colour data. New software has been made that encode each frame back to colour at the rate of a frame per four seconds.
