title: Seaborn HeatMap - How to set colour grading throughout multiple different datasets
body: <p>So I need to create a number of heatmaps in seaborn with varying datascales. Some range from 0-100 and some +100 to -100. What I need to do is to keep the colour grading the same throughout all graphs. So for example I want anything below 0 to be steadily getting from dark blue to light blue and anything above 0 to be getting darker red such as the terrible example graph below. </p>
  
  <p><a href="https://i.stack.imgur.com/1MBOe.png" rel="noreferrer"><img src="https://i.stack.imgur.com/1MBOe.png" alt="enter image description here"></a></p>
  
  <p>What I need that is not shown below very well is a fluid colour transition as currently I am not fully sure how seaborn is working it out as I have just listed a number of colours - Code below</p>
  
  <pre><code>sns.heatmap(df.T, cmap=ListedColormap(['#000066','#000099','#0000cc','#1a1aff','#6666ff','#b3b3ff','#ffff00','#ffcccc','#ff9999','#ff6666','#ff3333','#ff0000']), annot=False)
  </code></pre>
  
  <p>Thanks for any advise.</p>