Defining colors on the web.
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I know putting 'Hex Triplets' and 'Black Art' together suggests some form of witchcraft and wizardry. Unfortunately not, just some relatively simple mathematical concepts that we will refer to as we explore color on the web in more detail.
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RGB Color.
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 When we discussed Pixels we mentioned that the online variety were actually made up of a triad of red, green and blue elements. This is why both computer monitors, and the color range (gamut) are commonly called RGB (red, green and blue). This color system is also know as the additive system, where other colors are created by adding varying amounts of the red, green and blue primary colors. The resulting RGB color space (gamut) does not cover all light wavelengths (colors) that are visible to human eyes and is in fact significantly inferior in range to the subtractive CMYK gamut (cyan, magenta, yellow and black) used in offset printing and other professional color spaces. The RGB color space, developed by Hewlett-Packard and Microsoft Corporation, has been endorsed by the W3C (World Wide Web Consortium) and is the accepted standard for the internet. In essence, this is the color range that a web publisher has at their disposal. In the term 'Hex Triplets', the 'triplet' refers to the three primary colors - red, green and blue.
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Hexadecimal notation.
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The other part of the term 'Hex Triplet' is hexadecimal notation. Put simply, this is a numeric value that describes the amount of red, green and blue primary colors used to produce a resulting combined color. In 24-bit colors, there are 256 levels of each primary color, creating a total of 16,777,216 possible combinations (256 red x 256 green x 256 blue). Sometimes this is represented using numbers between 0 and 255 for each of the three colors, such as (255,0,0) for pure red, or (255,255,255) for white, the result of adding all of the primary colors together. However it is more common to use 'hexadecimal notation' to represent these numbers.
Back to some high school math. Most of the time, we live within a 10-base numerical system (decimal system), not really surprising when you consider that counting to ten is the limit of our fingers. You have also probably come across the binary system, the core of the digital world, where everything is either on or off, a 1 or a 0. The hexadecimal or hex numeric system is a world of 16 fingers, where the decimal numbers 11 through to 16 are represented by the letters A to F. Hex notation covers the full 16,777,216 possible 24-bit colors using only 6 digits or 3 pairs of 2 (a hex triplet). FF equals 256 (16 x 16) and therefore white is represented by the hex number FFFFFF (256 of each of red, green and blue). In the next section, we will look at some of the 16.8 million possible 24-bit web colors.
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