I Am Fascinated By Physics

The voltage drop across an LED seem to be directly proportional to the colour (energy) of the emitted light. e.g. red LEDs (wavelength c.660nm)have a voltage drop of about 1.8v and blue LEDs (wavelength c.450nm) about 3.3v.

If a LED needs 3.3v to emit blue light, how can a white LED (which must have a blue component) operate on only 3v?