We have been plotting in colour for say 8 years but its fairly limited, mono is say 95% colour shows stuff like we use blue for water, red for the gas & electricity, you get wet hitting a blue line a red line will kill you. As we are civil stuff like, line marking we do in cyan makes it easier to distinguish between existing and new, we show existing true size if its a 300 wide line thats what we show. Most of our background stuff is dashed 252 to indicate existing.