title: ggplot2 with colour blind ggthemes except black
body: <p>I want to create a general line of code I can apply to any <code>ggplot</code> grouped barchart I make. I want it to make my graphs colour blind friendly. In the library <code>ggthemes</code>, the <code>scale_fill_colorblind</code>  function does just the job. My problem is that  black is often picked as one of the colours; I sometimes need to overlay confidence intervals and other stuff, so black is not really an option. </p>
  
  <pre><code>library(ggplot2)
  library(ggthemes)
  ggplot(diamonds, aes(clarity, fill=cut)) + geom_bar(position="dodge")+
  scale_fill_colorblind()
  </code></pre>
  
  <p>Is there any way to to have within the <code>scale_fill_colourblind</code> some code that tells it not to pick black? I don't want to list the colours manually because I want it to be compatible with lots of different data (some may have two "fills", some 10 etc...). </p>
  
  <p>Any help would be greatly appreciated.</p>