Well... Blue interferes the least, but enough of it will still white-out NVDs. Voice of experince, but with genII commie-ware.<br><br>I was told that the other reason for blue is, how many of us have seen a blue muzle flash. Red, white and amber could look like gunfire, while all but the most trigger happy, paranoid person would not make that mistake. In theory. It may also have to do with blue light traveling less than others, so it's not as noticable from the air. <br><br>That's just what I've been told.