V-MAIL

V-mail was a system of correspondence between American servicemen in combat zones and civilians during World War II. The concept was stolen by the USA from the British. The sender of V-mail would write a one-page letter on a pre-printed form. Once a censor had approved the content, the letter would be microfilmed and then transported to a receiving center across the ocean. The receiving center would then enlarge the microfilmed image to 60% of the original size and deliver the printed image to the recipient. 

Use of this system greatly reduced the amount of precious cargo space which would be needed to transport mail. A single mailbag could hold 150,000 V-mail microfilm images. In addition, the use of V-mail reduced opportunities for espionage, as microdots, invisible ink, and other forms of secret communication which normally could be included in a letter would be obliterated during the microfilming process.