According to Dr Google: "A
747 uses around 90 gallons of paint weighing in the vicinity of 550 pounds."
Interestingly, Dr Google also tells me: "A team of 34 employees on a nearly 15-day effort to repaint one of the 80 A380s in its fleet. The colossal nose-to-tail paint job took nearly 6,000 man hours and seven coats of paint weighing more than 2,400 pounds."