i was hoping to plot two time series and shade the space between the series according to which series is larger at that time. here are the two series-- first in a data frame with an indicator for whichever series is larger at that time d1 <- read.csv("https://dl.dropbox.com/s/0txm3f70msd3nm6/ribbon%20data.csv?dl=1") And this is the melted series. d2 <- read.csv("https://dl.dropbox.com/s/6ohwmtkhpsutpig/melted%20ribbon%20data.csv?dl=1") which I plot... ggplot() + geom_line(data = d2, aes(x = time, y = value, group = variable, color = variable)) + geom_hline(yintercept = 0, linetype = 2) + geom_ribbon(data = d1[d1$big == "B",], aes(x = time, ymin = csa, ymax = csb), alpha = .25, fill = "#9999CC") + geom_ribbon(data = d1[d1$big == "A",], aes(x = time, ymin = csb, ymax = csa), alpha = .25, fill = "#CC6666") + scale_color_manual(values = c("#CC6666" , "#9999CC")) which results in... why is there a superfluous blue band in the middle of the plot?