illumination, aspects of technique



Gold Pigments Binders and general application Various supports	ILLUMINATION, ASPECTS OF TECHNIQUE Gold Stable, this superlative material is used par excellence in illumination and occurs in two forms, powder or gold leaf. The latter, requires delicate manipulation due to its extreme fineness and not withstanding the slightest draft. Gold is applied onto a mordant to assure adherence : In powder form, a mordant containing gum Arabic is mixed directly with the powder. For gold leaf, an egg mordant, or one made with crystal ammonia, or possibly one made from a plaster-based gesso if an embossed effect is desired. In this way contours are conserved, covered with a gold coating. In accordance to the technique adopted, illumination artistes will use a special agate stone to burnish work and reinforce brilliance. Pigments Innumerable, orpiment, murex, azurite, cochineal, porphyry, turmeric…etc, which may be ground, used in decoctions, mixed with gum Arabic or fish skin glue. From the beginning of antiquity the flourishing commerce in pigments contributed to the wide variety of colors found in manuscripts. All colors have either animal or mineral base origin. Reds, crimson or scarlet are obtained from lead oxide, cinnabar, kermès red or murex. Blues, different sources enable the artist to achieve various nuances. Lapis lazuli a semi-precious stone coming from Central Asia, is the most appreciated and also the most prohibitive. This ultramarine blue has a particular brilliance and depth. Due to its rarity, it would be used only for the most important elements such as the Virgin's robes. Yellows come from saffron, chélidione sap or orpiment. Binders and general application After preparation the pigments are combined with a binder, necessary to assure adherence to the support. In the Middle Ages, manuscripts were applied with a solution of gum Arabic, fish skin glue or maybe an egg based distemper. In this latter technique, egg, diluted in water serves as the binder for finely ground pure pigment. The mixing is performed at the last moment as distemper dries rapidly. An artist will apply thin successive coats, until the desired effect is achieved. As the work progresses, each shade is applied over the previous, pigments are not mixed avoiding undesirable reactions. A necessary pause between coats is made, for the first to dry and to allow for the support to regain its absorption ability. Depending on its position in an illumination, gold is applied at the beginning or otherwise in the last stages of the project and often with a well-defined shadow contour. This fastidious procedure has given us today, the possibility to admire nuances of incredible variety and freshness. Various supports Illuminations on papyrus scrolls exist, though rare and often found only at the introduction of a manuscript. Papyrus lacks the physical strength to support multiple coats of paint and cannot withstand humidity. As the plant only prospered in Egypt, a commercial monopoly applied. The technical development of parchment [dressed hide] had a direct contribution to the evolution of books and thus illumination. As the source material yielding parchment, veal, sheep and goats hide, was found everywhere, there was no longer a monopoly applying though high production costs continued. Parchment requires a lengthy preparation. The hide is tanned, washed, plunged into a lime bath to soften it and avoid decomposition, then rinsed, scraped, stretched out onto a frame, scraped again to remove all traces of fat and finally rubbed with a pumice stone rendering a thin surface apt for writing. A fine parchment comes from young, smooth skinned animals where the grain is more even and a lean hide is assured. Any presence of fat will obstruct the adherence of ink and paint. Vellum, the most prestigious parchment, comes from stillborn animals, veal or lambs and renders a very white and amazingly fine product. Paper in existence in China since the 5^th century AD is fabricated from plant fiber made into a pulp with water and dried. It found its way to the western world in the 11^th century, though used only for more basic and common applications. As time went on, paper mills multiplied and techniques improved until paper rivaled parchment at the end 15^th century.

	Catherine Auguste - catherine.auguste@cabinet-maker.com