[magick-developers] How to make grayscale

[David R. Snell]

What's the most efficient way to use PerlMagick to make a color image
grayscale?  I've been trying:

  $photo->Tint(fill=>'SlateGray3',opacity=>'50%');
  $photo->Tint(fill=>'SlateGray3',opacity=>'0.5');

But both of them generate "Internal Server Error" when called via browser, I
don't know why!?