Thin with water to the proper consistency. Tint with watercolor or gouache for pastel letters. Recommended by John Stevens and Peter Thornton. These are great - these colors flow out of a broad edge pen like ink. 1oz glass bottles with dropper top.
Colors can be mixed.
Truly waterproof when dry. The manufacturer says they are lightfast. For individual colors, specify color. The set is one of each color. Copperplate Gold is the most popular color.