title: Is there any good color map to convert gray-scale image to colorful ones using python's PIL?
body: <p>Matplotlib has a lot of good color maps, but is bad in performance. I'm writing some code to make gray-scale image colorful where interpolate with color map is a good idea. I wonder whether there are open source color maps available or demo code to use Pillow to convert gray-scale images into colorful ones via colormap?</p>
  
  <hr>
  
  <p>Clarify:</p>
  
  <ol>
  <li>Matplotlib is good for demo use, but bad performace for thounsands of images.</li>
  <li><a href="https://matplotlib.org/examples/color/colormaps_reference.html" rel="noreferrer">Matplotlib colormaps</a></li>
  <li>You can map grayscale images to colormaps to get colorful ones.</li>
  </ol>
  
  <p>Demo:</p>
  
  <p>The first image is grayscale, second is mapped in 'jet' cmap, third being 'hot'.</p>
  
  <p><a href="https://i.stack.imgur.com/BbmJ5.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/BbmJ5.jpg" alt="Matplotlib demo"></a></p>
  
  <p>The problem is that I do not know much about colors, and I'd like to achieve such effects in PIL for better performance.</p>