// Save this file in the macro folder as "Calculate_Black.txt".
// This macro will give the image tittle and calulates the 
// percentage of black pixels in an image.
// Addapted from the macro Calculate_Black_to_White_Ratio.txt

  requires("1.32g");
  if (bitDepth!=8)
      exit("This macro requires an 8-bit image");
  title = getTitle;
  black = 0;
  white = 255;
  getHistogram(0, hist, 256);
  total = 0;
  for (i=0; i<256; i++)
      total += hist[i];
   print(title,"\t", 100*hist[black]/total);