Colour

Example: Storage box
Picture source: Own storage box.

Figure 7.5.1 shows a storage box.

Number of Colours

   Under number of colours, we must not have too much colours in a design. In other words, we have to restrict the amount of colours our design have. 
    The design of the flowers in the storage box showin in Figure 7.5.1 only contained a maximum of 5 colours and not more, that is because too many colours will make the overall appearance very messy and not as attractive as before.

Colour Combination 
    In colour combination, it is better to use colours that are adjacent or opposing to each other in the colour wheel, 
    The combination of colour of the box pattern in Figure 7.5.1 uses the quadratic color combinations. It uses colors at 4 corners of a square or rectangle circumscribed in the color wheel, seen on the right. These four colours are red, yellow, green and blue.

Saturation
Example : Windows 8 start page
Photo source: Screenshot from own laptop.

Figure 7.5.2 shows Windows 8 start page.

Saturation is typically manipulated in colours to attract attention. Different degree of saturation in colours can give different effect.
The start page of Windows 8 shown in Figure 7.5.2 shows its icons uses saturated colours to attract attention compared to the less saturated green background 

Symbolism
Example: Door Card Reader
Photo source: Own house in Unijaya.

Figure 7.5.3 shows a card scanner
 with the card.

Figure 7.5.4 shows a card scanner beside a door.

Figure 7.5.3 and Figure 7.5.4 shows the card scanner of a door.

This card scanner uses green and red colour to symbolize its status. When considering the traffic lights, red symbolizes stop ,and green symbolizes go. Thus this device uses these 2 colour to symbolize its status as locked (red) and open (green).