- Jan 12, 2008
Minimum 2 wavelengths is for a specific colour. Look on the diagram posted earlier. The colours right on the 488-660 line show what colours those 2 wavelengths can make by varing the ratio between them. To make literally every colour you need all visible wavelengths and total control of them. That is not practical, but can be simplified to using just 3 RGB wavelengths. You just lose the colours outside the triangle.