A spectator selects a card from a deck. The performer says he has a silk with the replica of the selected card on it as a prediction. When he displays the silk it has several cards on it, which could cover most of the cards in the deck (including the selection) . The audience think this is a gag ! The silk is displayed clearly and completely on both sides, stretched flat between the hands.
He now asks the audience to name the selected card. Let us presume they name the Queen of Clubs. The performer snaps the silk, and it is found instantly transform into a large Queen of Clubs. It is again displayed clearly, stretched flat between the hands on both sides.
We supply you the special silk, ready to work. The "selected card" is forced, and this is designed for the Queen of Clubs.