title: d3.rgb().darker/brighter
body: <p>I'm using d3 to draw a bar chart, where the bars are used to compare different groups (e.g. men/women). For the filling I take a color which is saved in the data file (json) and vary it using <code>d3.rgb().darker()/.brighter()</code>.</p>
  <pre><code>.attr(&quot;fill&quot;, function(d){return d3.rgb(d.color).darker(1);})
  </code></pre>
  <p>It works in Firefox but in Internet Explorer 9 all the bars are shown as black (which is the first used color). I was wondering if this is just an issue with this browser in particular or if I am missing something to avoid this behavior.</p>
  <p>One solution would be of course to assign the colors individually, but if possible I'd like to use the provided possibilities.</p>