Contributors: Lawrence Houston
Burnishing is a process by which the surface of the paper is rendered less fibrous and spongy in appearance. This is accomplished by means of pressure applied by rubbing sized paper. This can be accomplished by machines, but was historically done by hand. Dry sheets of sized paper are placed on a flat surface and pressure is applied by rubbing a smooth, hard object across the surface of the paper. Typical objects that are used for burnishing include agate, glass, bone, and horn. Burnished paper is typically used for manuscripts or stationary work, where bleeding inks are a concern.
Calendared, Burnisher, Ahar
Synonyms in English
Similar to calendaring, burnishing tries to decrease the absorbency of paper to provide for better print quality and for manuscript paper. Heavily burnished paper can take longer to moisten when undergoing aqueous treatments and such treatments can be deleterious to the finish that the burnishing process provides.
The compressive forces exerted during the burnishing process reduces the thickness of the paper, and ink typically stays on the surface of the paper. Burnishing tends to obscure watermarks. It also lessens or distorts the appearance of the laid and chain lines of mould made papers. Heavily burnished paper, dyed with saffron, is common with Islamic paper manuscripts and miniatures.
Sizing of the paper normally involves a bath or brushing on of one of the following constituents: plant gums, egg ahar (egg whites mixed with water and alum), gelatin, and dilute wheat starch paste. Burnishing of paper is historically linked to the burnishing of papyrus, used to enhance its cosmetic appeal and also to render it more useful for writing. The process of burnishing papyrus is even discussed by Pliny in his Natural History (Naturalis Historia).
Improper burnishing can cause defects due to the intense pressure and dimensional changes effected locally in the cellulose fibers. The most frequent is cockling, caused by a non-uniform expansion of the paper as it is flattened. Metal burnishers can offset oxidation and abrasion products onto the paper and contribute to foxing or other aesthetic defects. Very intense pressure in localized areas of the paper can even cause it to gain a degree of translucency.
Pandey, Radha., 2012. Talk given to the Friends of Dard Hunter and International Association of Hand Papermakers and Paper Artists (IAPMA) on the traditional Indian papermakers.
Pliny. Translated by Rackham, H., 2005. Natural History. Book XII. Section XXV. Loeb Classical Library. Cambridge, Massachusetts.