Colour sets the mood.  

Colour is a key element in design as it is often the first observation people make. Research reveals people make a subconscious judgment about a person, environment, or product within 90 seconds of initial viewing, as colour is one of the first elements to be seen a majority of that assessment is based on colour alone. When choosing a colour for a uniform it is important to consider what a colour means and the mood or atmosphere it creates. The colour of your uniform range should complement your brand and working environmen.