title: Removing background color in holoviews image
body: <p>What is the correct way to specify the background colour for a Holoviews image? Here's the example I am using:</p>
  <pre class="lang-py prettyprint-override"><code>import holoviews as hv
  import numpy as np
  hv.extension('bokeh')
  eye = np.eye(10)
  hv.Image(eye).opts(clipping_colors={0: 'red'})
  </code></pre>
  <p>I also tried defining <code>clipping_colors</code> with other values like <code>NaN</code> or <code>&quot;0&quot;</code>, but they all give a faint blue background color as in the attached image. <a href="https://i.stack.imgur.com/7BFTz.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/7BFTz.jpg" alt="holoviews background color" /></a></p>