title: Changing the colour of a dodged barplot in ggplot2
body: <p>I'm currently struggling to change the default colours of a barplot I made. Since I used a value for the <code>aes(fill="")</code> argument the addition of <code>scale_colour_x</code> or <code>scale_fill_x</code> does not work. I'll provide you with the code I have and hope you'll find an easy way to solve my problem with me.</p>
  
  <pre><code>set.seed(123)
  platelay &lt;- data.frame(rown = rep(letters[1:8], 4),
                         coln = rep(1:4,each = 8),
                         colorvar = rnorm(32, 0.3, 0.2))
  </code></pre>
  
  <p>The example data (supposed to be a part of a 96 microwellplate with different fluorescence readouts per well)</p>
  
  <pre><code>ggplot(platelay,aes(x=rown,y=colorvar,fill=coln)) + 
  geom_bar(position="dodge",stat="identity")
  </code></pre>
  
  <p>The plot should give 5 bars (one for each <code>coln</code>) per <code>rown</code> and I want them to have colours which make it easy to distinguish each bar.</p>
  
  <p>This is what it looks like right now:
  <a href="https://i.stack.imgur.com/2Teh9.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2Teh9.png" alt="dodged barplot"></a></p>
  
  <p>As you can see the colours blend and the scale shows not only the distinct values 1 to 4 but also halves.
  I would appreciate the slightest bit of help, since I'm not really familiar with R or coding at all (just started learning it last week).</p>