Binary encoding of colours
The approach to encoding binary representations of colour is very similar to the approach we explored when looking at the encoding of Text_encoding.
We begin by determining the total number of colours and colour shades we want to represent. With this value established we then decide on the bit-length required that will accomodate this number of variations. Finally, we assign a binary number to each representation.
Greyscale
We can start with a limited palette: greyscale. Here there is black and white and number of interim shades of grey. The convention is to use an 8-bit number which, given \(2^8 = 256\) provides 256 shade variations.
In decimal, 0 is equal to black (zero light intensity) and 255 is equal to white (full light intensity). Some examples of this (including binary and hex representations are below):
Colour encoding
A single 8-bit number is sufficient for 256 greyscale combinations but with colour, the convention is to use three 8-bit numbers where each byte corresponds to a value for red, green and blue (RGB). Thus the overall bit-length is 24 (\(2^3 + 2^3 + 2^3\)). Each value corresponds to a light intensity for the given colour. Combined they are capable of representing all colours.
Some examples below
Red
Red is represented in RGB with all 8 red bits to set to 1 and the remaining 16 bits for the other two colours set to 0.
Yellow
Yellow is represented in RGB with both red and blue set to 1 and the remaining 8 green bits set to ):
