What is the simplest way to make just this plot grayscale (or perhaps black and white) rather than the default multi-colour:
xyplot(y1 + y2 ~ x, mydata, auto.key=TRUE)
I’ve seen discussion of creating new graphics devices or changing options for all plots, but is there an option that I can include perhaps in the xyplot() function itself that will convert the plot to grayscale?
For comparison: