Colour notation

Colour notation refers to the method used by colour models to identify and store colour values in a form recognisable to computer software and by digital equipment.

Colour models and notation
• The RGB colour model uses both decimal and hexadecimal triplets.
• Decimal RGB notation for orange is: R=255, G=128, B=0.
• Hexadecimal RGB notation for orange is: #FF8000.
• The HSB colour model uses decimal triplets.
• Decimal HSB notation for orange is: H=30.12, S=100, B=100.
• The CMYK colour model uses decimal quadruplets.
• The CMYK notation 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 then 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.

Notation, the written version of RGB colour values is 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