title: Change transparency for non-default color
body: <p>I have created my own color using the following command:</p>
  <pre><code>colorpalette Red, luminate(0(10)100, level) nograph
  return list
  foreach x of numlist 1/10 {
      local color`x' `r(p`x')'
  }
  </code></pre>
  <p>I can access and use these colors just fine, and the second color for example is</p>
  <pre><code>di &quot;`color2'&quot;
  156 0 0
  </code></pre>
  <p>However, problems arise when I want to add transparency. Say I am overlaying two histograms and want to add transparency, if I do something like</p>
  <pre><code>twoway hist somevar, color(&quot;156 0 0&quot;%30)
  </code></pre>
  <p>and here, it just ignores the %30 part. <code>color(red%30)</code> works fine, but  color(&quot;`color2'&quot;%30) does not.</p>
  <p>How can I add transparency with self-created colors after the creation? I would prefer not to recreate the whole colorpalette everytime that I want to change the transparency.</p>