title: Setting color palette in R
body: <p>I have been trying to produce a plot in just grayscale for the confidence interval fill and black lines for the predicted lines. I have tried every lead I find online and so far it has not produced a plot in grayscale. Much obliged for any help.</p>
  
  <p>For reference, Predictor 1 is a categorical variable (3 levels) and Predictor 2 is a continuous predictor variable.</p>
  
  <pre><code>library(ggthemes)
  ggplot() +
  geom_ribbon(data=yhat, aes(x=Predictor2, ymax=fit+se*1.96, 
  ymin=fit-se*1.96, fill=Predictor1), alpha=0.5)+ geom_line(data=yhat,
  aes(Predictor2, fit, color=Predictor1), size=1.5)
  +xlab('') + ylab('') + ggtitle('')+
  theme_few(base_size=14)+ scale_y_continuous(limits=c(0,1))+
  geom_abline(aes(intercept=0.5,slope=0),linetype="dashed")
  </code></pre>