What is your favorite color? Mine is blue.
Its blue because of the spectrum of visible light.
 I do not remember the science behind the light spectrum. My car is blue so that is why I like it.
Is well know that Blue is one of the three primary colours of pigments in painting and traditional colour theory
That is correct. I also like the color red.
You know that varieties of the color red may differ in hue, chroma or lightness.