Technique of the illumination

Gold, pigments, binders and general application and various supports...



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.


Orpiment, murex, azurite, cochenille, porphyre, curcuma...broyés, en décoction, mêlés à l'eau de gomme d'arabique ou à la colle de peau de poisson. Tout cela semble sortir d'un livre d'alchimie. Le commerce des pigments florissant dès l'Antiquité contribue à la variété des couleurs présentes sur les manuscrits.

Toutes les couleurs ont une origine soit végétale, soit minérale soit animale : - les rouges, cramoisi ou vermillon, sont obtenus à partir d'oxyde de plomb, de cinabre, de kermès rouge, de murex... - les bleus offrent de nombreuses nuances selon l'origine ; le lapis-lazuli, pierre semi-précieuse provenant d'Asie centrale, est le plus apprécié mais aussi le plus cher d'entre tous ; ce bleu outremer est d'un éclat particulièrement profond ; du fait de sa rareté, on le réserve aux éléments les plus importants comme la robe de la Vierge. - les jaunes proviennent du safran, de la sève de chélidoine, de l'orpiment. - les verts sont extraits de la malachite, du vert-de-gris, de l'argile verte... - le blanc vient de la céruse, très toxique et fabriquée à partir du plomb.

Pour être utilisables en tant que couleurs, les matières premières sont sujettes à une longue préparation : réduites en poudre très fine à l'aide de mortier et de pilon puis filtrées au travers d'un tissu, elles peuvent enfin être mêlées à un liant pour obtenir les diverses peintures.

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 5th 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 11th 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 15th century.