Editing High color (section)

==16-bit high color==
[[File:RGB_16bits_palette.png|thumb|RGB 16bits palette]]
[[File:7bit-each.svg|frame|Human eyes are more sensitive to green light. Discontinuities in the green gradient are easier to see than in the reds, and in the blues they are the hardest to see.]]

When all 16 bits are used, one of the components (usually green with RGB565, see below) gets an extra bit, allowing 64 levels of intensity for that component, and a total of 65536 available colors.

This can lead to small discrepancies in encoding, e.g. when one wishes to encode the 24-bit colour [[RGB]] (40, 40, 40) with 16 bits (a problem common to [[Chroma subsampling|subsampling]]). Forty in [[Binary number|binary]] is 00101000. The red and blue channels will take the five most significant bits, and will have a value of 00101, or 5 on a scale from 0 to 31 (16.1%). The green channel, with six bits of precision, will have a binary value of 001010, or 10 on a scale from 0 to 63 (15.9%). Because of this, the colour RGB (40, 40, 40) will have a slight purplish (''magenta'') tinge when displayed in 16 bits. 40 on a scale from 0 to 255 is 15.7%.  Other 24-bit colours would incur a ''green'' tinge when subsampled:  for instance, the 24-bit RGB representation of 14.1% grey, i.e. (36, 36, 36), would be encoded as 4/31 (12.9%) on the red and blue channels, but 9/63 (14.3%) on the green channel, because 36 is represented as 00100100 in binary.  

Green is usually chosen for the extra bit in 16 bits because the human eye has its highest sensitivity for green shades. For a demonstration, look closely at the following picture (note: this will work only on monitors displaying [[Color_depth#True color (24-bit)|true color]], i.e., 24 or 32 bits) where dark shades of red, green and blue are shown using 128 levels of intensities for each component (7 bits).

Readers with normal vision should see the individual shades of green relatively easily, while the shades of red should be difficult to see, and the shades of blue are likely indistinguishable.  More rarely, some systems support having the extra bit of colour depth on the red or blue channel, usually in applications where that colour is more prevalent (photographing of skin tones or skies, for example).