Blue is my favorite color.
Small world! I think blue one of the 3 true colors? 
It is one of three primary colors.
I've heard that you can only see blue if it's between certain wave lengths.
Yes when its between 450 and 495 nanometers.
Wow, that's a small range. It's crazy to think about all the colors you can't see with the human eye.
Most blues contain a slight mixtur of other colors. Can you believe that?