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Colour Space Rec.709

The TV color space Rec.709 was established in 1990.

Thinking about the colour management of a television production is a relatively new opportunity for producers.  Colour management applies to all devise that can present colour - for example: cameras, monitors and projectors, as well as printers or photochemical processes.

Two of the common terms used are:

  • Colour Space

A colour space is a system referring to the mathematical description of colour against a set colour system. There are a number of colour systems: RGB, CMYK, YUV, HSL, and the colour space describes which colours can be used. The extreme values or vertices of these coordinate systems are determined by the so-called primary colours. In an RGB colour model, the primary colours are red, green and blue. This is the colour palette that you can work with for your picture.

  • Gamut

A colour gamut describes the amount or range of any displayable colour within the gamut colours. So in real terms this means that the colour gamut of the DCI-P3 colour space ( for delivery to cinema projectors), contains colours that do not exist in the gamut of the Rec709 HDTV colour space ( because it is smaller than P3). How big a colour space, and, consequently, how many colours contained in the gamut, depends on the physical capabilities of the monitor or the camera.  The term wider colour gamut is used to refer to a higher number of colours than Rec.709.

Rec.709

In film and television, the colour space by the ITU (International Telecommunication Union) is standardised for HDTV; this is specified in the standard ITU-R BT.709. The HD colour space is only part of the much more extensive specification, but the name of the standard is generally used interchangeably with the colour space designation. 

In ITU-R BT.709 the colour space is defined as:

  • a resolution of 1920x1080 or 1280x720 pixels and thus necessarily an aspect ratio of 16: 9 and square pixels
  • 10 bit and 4: 2: 2 (RGB 4: 4: 4 is possible )
  • Specified refresh rates: 60, 50, 30, 25, 24, 59.94, 29.97, 23.98
  • image recording and transmission / playback can be progressive, interlaced, or progressive segmented frame (psF) carried
  • black level at 64 and white level at 940
  • peak brightness 100 nits ( cd / m²)
  • White point (illuminant) D65, which corresponds to a colour temperature of 6500K


The Rec.709 colour space is a RGB colour space, and is similar to the standard RGB (sRGB) colour space. The gamut of Rec.709 is relatively small. It has only about one-third of the colours that are visible to the human eye, and only slightly more than half of the colour standard Rec.2020 .


Rec.709 vs. Rec.2020

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