title: Convert colored image to back/white image
body: <p>I am working on converting colored image to black and white image. I am using BufferedImage for this with the type of TYPE_BYTE_BINARY. But output image is not converted correctly. For example, if image contains blue letters on black background, result image for this part is totaly black. Can anybody help me? My code is below.</p>
  
  <pre><code>//Invert the colormodel
  byte[] map = new byte[] { (byte) (255), (byte) (0) };
  IndexColorModel colorModel = new IndexColorModel(1, 2, map,
  map, map);
  
  BufferedImage bufferedImage = new BufferedImage(
  img.getWidth(null), img.getHeight(null),
  BufferedImage.TYPE_BYTE_BINARY, colorModel);
  Graphics2D g2 = bufferedImage.createGraphics();
  g2.drawImage(img, 0, 0, null);
  g2.dispose();
  </code></pre>