Letterpress can use Pantone colors just like other types of printing. We prefer to mix our own ink from Pantone base colors using the Pantone formula guide. This means we don't have to buy a pound of ink when we really only need a small spoonful for the project. We mix ink to match other things too - like paper stock, fabric, other pieces in a business system produced on offset presses. We use soy based inks whenever possible. The important thing is remembering not to taste the ink.