Page:The chemistry of paints and painting.djvu/41



PAPER, VELLUM, IVORY

paper is used as the painting-ground for the vast majority of works executed in water-colours, and as this method of painting offers but slight protection to the pigments employed against hostile influences, it becomes of the greatest importance to ascertain that no unnecessary elements of danger are introduced in the paper itself. We will now proceed to consider briefly the sources and constituents of drawing-paper.

Linen from the common flax (Linum usitatissimum), and in the form of white rags, should be the basis of the pulp used in the making of sound drawing-paper. In actual practice the cheaper and weaker fibre of cotton (seed-hairs of Gossypium sp.) has almost entirely displaced flax, although during recent years a successful attempt has been made in England to produce a high grade of hand-made drawing-paper almost wholly composed of linen. Other vegetable fibres might, no doubt, be employed for this purpose. Thus, Japanese paper, prepared from the bast-fibres of the paper-mulberry (Broussonetia papyrifera), were it made less absorbent by the introduction of a sufficiency of size, would probably become an efficient, strong, and durable substitute for linen-paper; but at present linen-papers, cotton-papers, and papers made from a mixture