Bernie, the Pitt pen I refer to is manufactured by Faber-Castell and are called a Pitt artist pen. I'm able to buy them from Hobby Lobby, but any store that sells artist supplies should have them. They come in various colors, various tips and are essentially waterproof Indian ink pens. I use them on occasion to highlight panel lines. They work extremely well to highlight panel lines with NMF finishes, see T-33 below, but also on others as well. Run the pen down the panel line then take a Q-Tip or soft cloth and rub across the line to remove any excess. Works for me.
1 attached image. Click to enlarge.
