Quarantine "yellow jack" but this was also a name for yellow fever, which probably derives its common name from the flag, not the color of the victims (cholera ships also used a yellow flag). The plain yellow flag ("Quebec" or Q in international maritime signal flags) probably derives its letter symbol for its initial use in "quarantine", but this flag in modern times indicates the opposite—a ship that declares itself free of quarantinable disease, and requests boarding and routine port inspection. Australia has perhaps the world's strictest quarantine standards. Quarantine in northern Australia is important because of its proximity to South-east
Flag of Australia have trouble displaying the shade of blue in the table above. The flag may be reproduced in a single colour, with the colour being either black or one of the two colours of the flag, albeit blue is generally preferred for single-colour productions. Guidelines for flying the flag are laid out in the 1953 Flags Act and in a pamphlet entitled "The Australian National Flag", which is published by the Australian Government on an infrequent basis. The guidelines say that the Australian National Flag is allowed to be flown on every day of the year, and that it "should be