# Colour values

Colour values are the sets of numbers and/or characters used by colour models to systematically identify and store colour information in a form of colour notation recognisable to both computers and humans. Every colour within a colour model is assigned its own unique colour value.

###### Colour models and notation

The RGB colour model uses both decimal and hexadecimal triplets for colour notation.

• The decimal RGB colour value for orange is: R=255, G=128, B=0.
• The hexadecimal RGB colour value for orange is: #FF8000.

The HSB colour model uses decimal triplets for colour notation.

• The decimal HSB colour value for orange is: H=30.12, S=100, B=100.

The CMYK colour model uses decimal quadruplets for colour notation.

• The CMYK colour value for orange is: C=0, M=61.48, Y=100, K=0.
###### RGB colour notation

RGB colour values are expressed as decimal triplets (yellow = 255, 255, 0) or hexadecimal triplets (green = #00FF00). Computer software is programmed to recognise RGB colour values.

In both cases, the triplets determine the amount of red, green and blue used to produce a specific colour.
A decimal triplet is made up of three numbers between 0 and 255 divided by commas.
A hexadecimal triplet starts with a # sign followed by three two-digit numbers with values between  00 and FF written without spaces between.

RGB colour values are based on decimal notation (triplets with a base 10) or hexadecimal notation (triplets with a base 16).

• Decimal notation uses 10 digits from 0 to 9 as follows, 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9.
• The hexadecimal notation uses 16 digits from 0 to F as follows, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E and F.
• Hexadecimal notation for values between 16 and 31 are as follows 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 1A, 1B, 1C, 1D, 1E and 1F.
###### RGB decimal notation
• In decimal notation, an RGB triplet is used to represent the values of red, then green, then blue. A range of decimal numbers between 0 to 255 can be selected for each value.
• Red = 255, 0, 0
• Yellow = 255, 255, 0
• Green = 0, 255, 0
• Cyan = 0, 255, 255
• Blue = 0, 0, 255
• Magenta = 255, 0, 255