the reconstructed colours. Due to the alternating property of PAL, it is possible to narrow the colours down to 4 possibilities, requiring much less guesswork compared to e.g. NTSC. Distortions in the geometry of the telerecordings due to the nature of physically recording from a non-flat CRT screen onto film means that a transformation has to be applied in order to infer the original positions of the chroma dots within the broadcast. However, these technical obstacles were finally overcome in 2008, and software written by developer Richard Russell at the informal Colour Recovery Working Group was put to use, finally resulting in the broadcast and release of colour-recovered episodes of Dad's Army and Doctor Who, and subsequently two episodes of The Morecambe & Wise Show as well as the "Party Political Broadcast (Choreographed)" sketch from Monty Python's Flying Circus Example of the chroma dot reconstruction: See also Reverse Standards Conversion References External links A visual comparison showing the resulting differences between traditional colourisation and Colour recovery Pictures of a Marconi quick-pull-down 16mm Film Recorder of the kind used to record Dad's Army and Are You Being Served Film and video technology