He then removed the deckle and passed the mould to a second worker, the coucher.
The coucher laid the mould face down onto a sheet of felt and pressed it with a rocking motion, transferring the wet sheet from the wire to the felt. Another felt was laid on top, and the process was repeated. In this way, a pile of alternating felts and sheets, called a post, was built up. A team working together could produce several thousand sheets in a working day. In the meantime, the vatman used a second mould, so that work at the vat continued without pause.
When the post was complete, it was placed in a large screw press, and several workers pulled on a long lever to squeeze out as much water as possible. The sheets, now firm enough to handle, were separated from the felts by another worker and pressed again in a pile without felts. They were then taken to a drying loft, an upper floor with shutters along its sides that could be opened or closed to control the flow of air. The sheets were hung in small groups over ropes made of horsehair or coated cord, and left to dry slowly.
Dried sheets intended for writing were then sized. They were dipped in a warm solution of gelatin, made by boiling down hides and other animal scraps, then pressed and dried again. Sizing made the surface firm and resistant to ink. Finally, the sheets were finished. They might be pressed between smooth metal plates or rubbed with a burnishing tool to give a smooth surface. They were inspected, and damaged sheets were set aside. The good sheets were counted into quires, usually of about two dozen sheets, and the quires were gathered into reams. A ream traditionally contained twenty quires, a quantity that varied slightly in different places and periods but came to be fixed at five hundred sheets.
The process required many workers, each with a particular task, and it depended on the skill of experienced hands. A mill’s reputation rested on the quality of its sheets, and skilled vatmen and couchers were in demand. Papermaking families often passed their knowledge from one generation to the next, and the craft spread as workers traveled from mill to mill.
VI. New Fibers and New Methods
As literacy and printing expanded, the demand for paper rose steadily, and the supply of rags became a serious constraint. Mills competed for rags, prices rose, and governments sometimes took measures to keep rags within their borders. The search for ways to make paper faster and from other materials became a central concern of the industry from the seventeenth century onward.
The first major improvement came in the Netherlands in the late seventeenth century, with the invention of a new kind of beating machine that came to be called the Hollander. In place of the stamping hammers, the Hollander used an oval tub divided along the middle by a partition. On one side of the partition, a heavy roll fitted with metal bars rotated rapidly over a bed plate also fitted with bars. Rags and water circulated around the tub and passed again and again between the roll and the bed plate, where they were cut and frayed. The Hollander produced pulp much faster than the stamping mill and required less water power. It tended to cut fibers shorter than the hammers did, which affected the strength of the paper, but its speed made it widely adopted, and machines based on the same principle remained in use for centuries.
The problem of raw material remained. In the eighteenth century, several writers and experimenters proposed making paper from plant materials other than rags.