One would think that white is a relaxing colour, but it doesn't seem to be the case for me in winter. Today's images seem more relaxing with the even lines and curves in green.
The most relaxing colour is the colour of the sky and the ocean - blue. It is considered peaceful and tranquil and causes the body to produce calming chemicals. That's why it is often used in bedrooms.
The next soothing colour is green - but it is the sage green. That's the one we see in hospitals on walls and hospital gowns - in the old days. The exit signs on highways are dark green backgrounds with white letters. That's because it has been determined that a driver's eyes don't get as tired looking at print on a green field, and there's still enough contrast for easy character recognition.