Page:Paper and Its Uses.djvu/42

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PAPER AND ITS USES

either sold at a further reduction or is returned to be repulped. If the order is for specially watermarked paper, or is for all "insides" or good paper, the "retree" and "broke" will both return for re-making.

Machine-made writing papers which are to be sized with gelatine are usually first sized with resin, so do not come forward as waterleaf. The sizing room is long, high, comparatively narrow, containing a small sizing machine and numerous drying cylinders. The reel of paper is mounted on brackets in front of the sizing trough, the web passes between metal rollers, beneath the surface of the warm size, out and between squeezing rolls which remove the excess of gelatine, and then forward for drying. Up to the roof, and down to the floor, over skeleton drums, the web of paper travels until it is thoroughly dried, in a temperature equal to that of the drying lofts. At the end of the room the paper is reeled again, and when in a fit state goes either to the super-calenders, or, if the paper is to be plate-rolled, it is cut and the surface imparted as described for hand-made papers.

Papers which are merely to have "machine-finish," that is, the surface imparted by the calenders of the paper machine, receive no further treatment before being cut into sheets. Those papers which are to be super-calendered (S.C.) pass through a large super-calendering machine, consisting of a number of chilled iron rolls and rolls of compressed cotton or paper alternately. The weight of the rolls is enormous, and although extra pressure can be applied, it is not often necessary. A very high degree of finish can be given by means of the super-calenders, and the majority of papers with a glazed finish have passed through this machine.

Papers which are to receive a water finish are