Blue
Associated with: calming and soothing; promotes intellectual thought; believed to keep hunger at bay; loyalty, serenity, authority, protection, contemplative, prevents nightmares
Best for: bedrooms, bathrooms, studies
Pitfalls: can look cold and unwelcoming. Make sure it doesn't look too chilly by choosing a blue with a warm undertone

Brown
Associated with: security, stability and very practical
Best for: living rooms
Pitfalls: introduce a livelier colour for mental stimulation such as green or blue

Red
Associated with: danger, passion, energy, warmth, adventure, optimism
Best for: dining rooms as it promotes sociable and lively feelings, and stimulates the appetite
Pitfalls: it can be overpowering and lead to headaches. Either vary the shade, paint one wall red, or use it for accessories only. Don't use red in a baby's room