title: How to determine if an image is monochromatic
body: <p>I have to determine if an image is monochromatic.  I mean by monochromatic not only Black and white.. it could be Sepia, like Red or blue shaded, or even mixed Red and blue shaded a.s.o (mono color scaled) ?</p>
  
  <p>I think we can say that the scale goes from black (0,0,0) to White (255,255,255) bu it is not linear.. it's a specific curve on each color channel</p>
  
  <p>I hope I am clear :)</p>