Colour value

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 recognizable to both computers and humans. Every colour within a colour model is assigned its own unique colour value.

RGB colour model

The RGB colour model uses both decimal and hexadecimal triplets for colour notation. Each of the three components within a triplet contains a value corresponding to red, green or blue. The colour values within RGB triplets appear as follows:

• The colour values in decimal notation for orange: R=255, G=128, B=0.
• The colour value in hexadecimal RGB notation for orange: #FF8000.
HSB colour model

The HSB colour model uses decimal triplets for colour notation. Each of the three components within a triplet contains a value corresponding to hue, saturation or brightness. The colour values within HSB triplets appear as follows:

• The colour values in decimal notation for orange: H=30.12, S=100, B=100.
CMYK colour model

The CMYK colour model uses decimal quadruplets for colour notation. Each of the four components within a quadruplet contains a value corresponding to cyan, magenta, yellow or black. The colour values within CMYK quadruplets appear as follows:

• The colour values in decimal notation for orange: C=0, M=61.48, Y=100, K=0.
RGB colour values

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 comprises 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: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9.
• The hexadecimal notation uses 16 digits from 0 to F: 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 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 1A, 1B, 1C, 1D, 1E and 1F.
RGB decimal values
• In decimal notation, an RGB triplet represents the values of red, 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