Stitching Blogger's Question of the Week: Chart Marking

Do you mark or hi-lite your patterns or can you follow them without any markings? Do you make copies to mark up, or do you mark originals?

I've only recently begun marking charts. I only do it with black and white ones which are particularly difficult to read. At the moment I'm marking an enlarged copy of "Above the Clouds". I'm doing this because this design is quite difficult because of all the blended threads.

I never marked coloured charts.