title: How to test GUI for color blind person?
body: <p>Is there a way to test if a GUI is usable for color blind person?</p>
  
  <p>I know that it has many degrees and I guess that's why simply doing a screenshot in black &amp; white is not the best way to test the usability of a GUI for a color blind person. What is the best way or best tool to do it?</p>