An effect by Roy Walton. The most colorful packet trick ever. What a fantastic routine this is. A packet of four blue-backed cards (say all 8 of Clubs) changes to red-backed cards, then to green backs and then to yellow. Then the four cards are one of each color and, for a stunning finish, the four cards change into the four Aces (or blank cards or Jokers)!
Requires regular cards with different colored backs.