Taking DWins example.
What I often do, particularly when I use many, many different plots with the same colours or size information, is I store them in variables I otherwise never use. This helps me keep my code a little cleaner AND I can change it "globally".
E.g.
clab = 1.5
cmain = 2
caxis = 1.2
plot(1, 1 ,xlab="x axis", ylab="y axis", pch=19,
col.lab="red", cex.lab=clab,
col="green", main = "Testing scatterplots", cex.main =cmain, cex.axis=caxis)
You can also write a function, doing something similar. But for a quick shot this is ideal. You can also store that kind of information in an extra script, so you don't have a messy plot script:
which you then call with setwd("") source("plotcolours.r")
in a file say called plotcolours.r you then store all the e.g. colour or size variables
clab = 1.5
cmain = 2
caxis = 1.2
for colours could use
darkred<-rgb(113,28,47,maxColorValue=255)
as your variable 'darkred' now has the colour information stored, you can access it in your actual plotting script.
plot(1,1,col=darkred)