title: Manual colour for points in ggplot2
body: <p>I have a factorial graph and I would like to have control over the colours chosen for each line/point in the graph. I have checked online resources, and have seen I should use the <code>+scale_color_manual()</code> function within ggplot2. </p>
  
  <p>Although this creates the desired output, it also creates an extra legend that I do not wish to have:
  <a href="https://i.stack.imgur.com/fkeV3.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/fkeV3.jpg" alt="enter image description here"></a></p>
  
  <p>What is the correct way of achieving the manual control over lines without creating the extra legend, please?</p>
  
  <p>Code:</p>
  
  <pre><code># load library
  library(ggplot2)
  
  # intialise random seed for reproducibility
  set.seed(42)
  
  # generate fictitous averaged data
  age &lt;- gl(2, 4, labels = c("Younger", "Older"))
  sequence &lt;- gl(2, 2, 8, labels = c("ABA", "CBA"))
  response &lt;- gl(2, 1, length = 8, labels = c("Repetition", "Switch"))
  accuracy &lt;- runif(length(age), min = 0.90, max = 1)
  se &lt;- runif(length(age), min = 0.002, max = 0.008)
  
  # collate into data frame
  data &lt;- data.frame(age, sequence, response, accuracy, se)
  
  
  # do plot
  pd &lt;- position_dodge(0.08)
  
  plot &lt;- ggplot(data, aes(x = sequence, y = accuracy, group = response, 
                          colour = response))
  plot &lt;- plot + geom_errorbar(aes(ymin = accuracy - se, ymax = accuracy + se), 
                               width = .15, size = 0.5, position = pd)
  plot &lt;- plot + geom_line(aes(linetype = response), position = pd)
  plot &lt;- plot + geom_point(aes(shape = response), size = 2.3, position = pd)
  plot &lt;- plot + scale_x_discrete(name = "Task Sequence") + 
    scale_y_continuous(name = "Accuracy (Proportion)")
  plot &lt;- plot + scale_shape_discrete(name = "Response") + 
    scale_linetype_discrete(name = "Response")
  plot &lt;- plot + facet_grid(  ~ age) 
  plot + scale_color_manual(values = c("#999999", "#E69F00"))
  </code></pre>