Print publication usually ask to use CMYK (instead of RGB) color mode for figures (because not every color can be print out), while we usually use RGB for screen reading (because screen has larger range of color scale). Of course we can convert RGB to CMYK in external software, like PS. But why not using CMYK directly while producing original figures in R?
> pdf(“test.cmyk.pdf”, colormodel=’cmyk’)
> pie(1:10, col=1:10)