Retention of vision

Retention of vision is a conjuring term referring to the perceived image of an object during a vanish (usually associated with vanishing coins). In a retention of vision vanish, the spectator sees a coin placed on a palm and as the fingers are closed around the coin it is secretly removed, but because the retina still retains a fleeting image of the coin for a fraction of a second, the spectator will be convinced that the coin was placed in the hand, when in fact it wasn't.