Hexadecimal Colour Codes

Look at the picture on the right. Can you give a unique name to each of the colours displayed on the picture? (e.g. Lemon yellow, sunset yellow, tangerine etc.)

Do you know your colour codes? When building websites or Graphical User Interfaces (GUI) for your computer programs you will have to choose the colours you want to use.

In computing we can identify a colour using a unique colour code which consists of a # followed by 6 digits. This is called the hexadecimal RGB colour code. RGB stands for Red, Green and Blue. These 3 colours are in computing the the primary colours: which means that every colour is made of a combination of these three colours.

For instance, magenta (shade of purple) is made of a lot of red and a lot of blue and no green at all. Its colour code is #FF00FF, which is the hexadecimal equivalent of (255, 0, 255). It’s a bit like mixing paint: each colour is made of a bit of red paint (from 0 to 255), a bit of blue paint (from 0 to 255) and a bit of green paint (from 0 to 255). We can then convert these three numbers to hexadecimal.

Using this approach we can uniquely identify 255 x 255 x 255 = 16 million different shades of colours.

When choosing your colors you can use a site like colorpicker.com.

Check the following RGB Color picker to see how RGB codes work (Works best using IE):

Match the Colour Codes:

Complete this drag and drop activity to match the colours with their hexadecimal colour codes.

#C40000

#000000

#00FFFF

#00FF00

#750075

#AAAAAA

#FFFF00

#333333

#9999FF

#FFFFFF