A raising card is used in the process of gigging, or producing the nap of cloth.
[1] Originally, only woolen cloth was raised, but now gigging is used on rayon, silk, and cotton fabrics to create a soft, lustrous nap.
It was first done using the dried fruit pod of a teasel plant, then technology moved on and raising cards were created.
[2] The process was mechanized during the industrial revolution, and the raising machine (the gig-mill) looks and works much like the large carding machines, in that it has a large main roller with several small ones positioned around it.
In order to gain an even surface, the nap is then sheared, or cut, to the desired height.