the to surface of the wet sheet. Any other water is removed as the sheet is passed over steam-heated cylinders. Chemical bonds that hold the finished sheet together also take place at this step. The next stage is known as calendaring, pressing between smooth chilled rolls to produce the smooth finish known as machine finish. At the end of the Fourdrinier machine, the paper is slit by revolving cutters and wound on reels. The production of the paper is completed once the sheets are cut into smaller sections, unless the paper is to be used on a continuous press that uses rolls of paper. Special papers are given additional treatment. Supercalendered paper is subjected to a further calendering process under great pressure between metal and paper-covered rolls. Coated paper, such as is used for fine halftone reproduction, is sized with clay or glue and calendered. Paper is usually sold by the ream, in sheets of standard sizes. A ream of paper usually contains 480 sheets, but reams of drawing paper and handmade paper contain 472 sheets. Book paper and newsprint for flat-plate printing are sold in reams of 500 sheets and in perfect reams of 516 sheets. The most common book-paper size is octavo (112 by 168 cm/44 by 66 in). Newsprint for rotary-press printing comes in rolls of varying sizes; a typical roll of newsprint, as used by large metropolitan newspapers in the U.S., is about 168 cm (66 in) wide, 7925 m (26,000 ft) long, and weighs about 725 kg (1600 lb). In the United States alone, the consumption of paper and paperboard averages about 660 pounds per person each year and about 64 million metric tones of paper and paperboard are produced annually. With such great demand, papermaking is continuously being improved and modernized, and new machines are constantly being developed....
