Writing Paper: Rag Sheets Sized and Hot-Pressed Smooth

A pen needs paper that does not let ink spread: sized, so the ink stays on top, and smooth, so the nib does not catch. Andrew Ure (1839) gives both: hand-made rag sheets dipped in gelatine size, then hot-pressed between smooth pasteboards and heated iron plates, "which communicates a fine smooth surface to writing-paper". The picture: the drying loft of an 18th-century paper mill, sheets hung on lines (Diderot's Encyclopédie).