Colour recovery

rdf:langString Colour recovery

rdf:langString Colour recovery (or colour restoration) is a process which can restore lost colour to television programmes which were originally transmitted from the colour video tape which the original master was recorded on during final production prior broadcast, but for which only black and white copies remain archived. This should not be confused with colourisation, in which colour is artificially added to source material that was always black-and-white (or where no colour information was preserved in the black-and-white copy), or used to enhance poor-quality original sources. Colour recovery is a newer process and is fundamentally different from colourisation. Most of the work has been done on PAL signals due to the BBC, but the concept is not fundamentally restricted to this system. Colour recovery can be based on combining colour information from lower-quality recordings, or in the case of BBC's new method, the particular effects that are created when colour source material is encoded into the common analogue television format PAL and then played back. In early colour televisions, until the mid-1980s, this could lead to a problem known as dot crawl because the encoding of colour information could interfere with the underlying signal. This causes a form of distortion in the output signal displayed on the screen. This pattern is evident even if the resulting image is recorded on film, even in black-and-white film. Colour recovery looks for these tell-tale patterns and uses them to decode the original colours. As of 2018, colour recovery has successfully been applied to episodes of the BBC TV programmes Doctor Who, Dad's Army, Are You Being Served? and The Morecambe & Wise Show.