INK RUB
A defect, often associated with matte-coated papers, in which parts of a dried ink film are removed by pressure or friction from another surface.

INTEGRATED MILL
A mill that starts with logs or wood chips and first produces wood pulp which it then processes to make paper or board.

INTERMITTENT BOARD MACHINE
A machine for producing sheets of thick board by winding the web formed on a Fourdrinier wire or cylinder mold(s) around a making roll to form a sheet consisting of several layers. When the thickness is sufficient the layers are cut, so forming a sheet that is removed from the machine for drying and any further processing.

INTERNAL SIZING
The addition of materials to the stock, generally in order to increase the resistance of the finished paper to the penetration and spreading of aqueous liquids, e.g., writing ink. Frequently described as Engine Sizing.

IVORY BOARD
High-quality board made in white or colors with a bright, clear appearance, particularly used for business cards and similar high-class printed work. Original Ivory Board was and still is made in Holland, although the grade is made in many countries.