Which color option should I choose?
The colors you choose for your envelope often depend on its intended purpose. Remittance envelopes, for example, are typically printed one-color (often black), while direct mail envelopes are often designed full-color to stand out in a pile of mail.
Two-color printing, as its name implies, uses two ink colors. One is typically black, but it doesn't have to be. One-color printing uses just a single color of ink. Again, black is most common, but you can choose a different color if you prefer.