When reading this question, I started to think whether it would be possible to convert colors to imitate an average greyscale printer (assuming that your screen is calibrated)? Finding an approvable approximation would save paper.
For example, how to convert these colors to see whether the light and dark blues and reds can be differentiated on paper?
temp <- rgb2hsv(239, 138, 98, maxColorValue=255)
Rl <- hsv(h = temp[1,], s = 0.5, v = 1)
Rd <- hsv(h = temp[1,], s = 0.5, v = 0.4)
temp <- rgb2hsv(103, 169, 207, maxColorValue=255)
Cl <- hsv(h = temp[1,], s = temp[2,], v = 1)
Cd <- hsv(h = temp[1,], s = temp[2,], v = 0.4)
plot(1:4, type = "p", col = c(Rl, Rd, Cl, Cd), pch = 19, cex = 8, xlim = c(0,5), ylim = c(0,5))
