Prior to more contemporary, automated equipment, letters were manually turned the same direction to facilitate rapid, automated postmarking and sorting of mail. Current equipment performs this task automatically, including both flipping and rotating envelopes and postal cards to have them placed in the proper position for cancellation. The use of phosphorescent ink in stamp printing provides a "target" for such equipment to seek, where the envelope is positioned up to four times before being cast out of the system as not having postage. All of this is done at high speed.