Colours have a specific vibration that generate certain states in humans after visualising them. The state of being Calm after looking at a sea of blue, for example. And the state of deep Contemplation when seeing violet skies.
There are numerous studies and efficient therapies that revolve around colours and their effects on humans, however, this is not something to be reasoned about all the time. Sometimes it’s best to experience it for yourself. Just look at it and be free!