black and white tv came to australia in 1975.
black and white tv came to australia in 1975.
when did black and white tv come to australia?
1975
Na
Na
black & white tv systems predate colour, and so subsequent analogue colour broadcast systems have been designed with backwards-compatibility in mind (known as a "compatible colour" system). thus, the chrominance (colour) signal is typically 'shoe-horned' into the same channel as the luminance (brightness) signal, modulated on a fixed frequency, known as the "colour subcarrier". black and white televisions do not decode this extra colour information in the subcarrier, using only the luminance to provide a monochrome picture. however, due to limited bandwidth in the video channel, the chrominance and luminance signals bleed into each other considerably, resulting in the colour information showing up visibly as chroma crawl, or chroma dots on black & white tv sets. this is normally considered a nuisance in analogue broadcasting. however, since telerecordings were made from black & white tv screens and technicians at the time often decided not to apply a filter to remove this interference, these patterns are retained even in the existing monochrome film prints and theoretically contain the original colour information. (occasionally the colour information was filtered out using a notch filter and is lost.) the idea to recover this information was originally suggested by bbc researcher james insell.
colour recovery