oilpaper

Oilpaper, or oiled paper, is a sheet of paper impregnated or coated with a drying oil to impart water resistance and flexibility. Common oils include linseed oil, tung oil, or resinous varnishes. The process involves soaking or brushing the oil into the cellulose fibers and allowing it to cure, forming a protective film.

In the 19th and early 20th centuries, oilpaper was used for waterproof wrappers, book covers, maps, and as a lightweight protective layer for archival materials. It also appeared as a surface for drawing or painting in some experimental artistic practices. The use of oilpaper declined with the development of more durable waterproof coatings and plastics.

Oilpaper is somewhat translucent and can darken or become brittle with age. It may become tacky in humid conditions, and the oil content can migrate to adjacent surfaces, causing staining. While more water resistant than untreated paper, it can be affected by solvents and heat, making it less suitable for long‑term archival storage due to aging of the oil.

Manufacturing methods include dipping sheets in oil or coating with oil‑based varnish, sometimes followed by a wax finish to improve water resistance. Variants may use different drying oils or resinous additives to alter flexibility and wipe resistance. Oilpaper remains a historical example of early parchment-style waterproofing for paper-based materials.