What it looks like: The paper-like foil leaves a metallic design behind.
How it's done: A heated copper plate is used to push the foil into the paper, which leaves an impression much like letterpress. This printing process is considered "dry printing" because it doesn't actually use any ink.
Paper pointers: Create a dramatic effect using lighter foils (like silver and white) on darker papers. Keep in mind, though, that your design options are more limited because thin, delicate lines won't show up very well. Too much foiled text is difficult to read, so it's best to restrict it to key words, borders or intricate designs.
Ink tips: It's not ink, per se, but know that a little goes a long way.
Turnaround time: Foil stamping is the most expensive printing process and is often outsourced, which means a longer turnaround time. The process can take around 10 business days.