The mental associations of colours give them a symbolism that can vary according to cultures and individuals. Blue is the favorite colour of Westerners, it has a positive meaning. It evokes the colour of the sky, and oceans. In this same perspective, we can even say that it pushes us to knowledge, to the understanding, to the fundamental questions, to the depth of things.
It is also the allegory of peace (flags of the UN and European institutions that are blue).
The “blue” colour field includes many shades that are either saturated, such as ultramarine blue, desaturated, such as sky blue, or light, or dark like midnight blue. It ranges from blue-green or turquoise to ultramarine blue and purplish blue.
The wavelengths of the blue lights range from about 450 to about 500 nanometers; including blue-violet and blue-green. The CERN blue is at about 472.82 nm.