Cyan Sharpies as Ink Resist Pens

Many of us use Sharpies for ink resist pens when the inevitable minor flaw in a press-n-peel transfer occurs. Recently I've been making a number of boards and have noticed that cyan Sharpies seem to be way more resistant to warm Ferric Chloride than black Sharpies.

I had been using cyan for a while simply because I couldn't find a black and could not remember to pick one up at the store. However, when I did finally get a black I used my same two coat procedure with a 5 min dry time for each coat and had terrible results. The black Sharpie almost completely dissolved. I went back to cyan and the problem was solved.