The type of document that this blog will focus on from here on out is called an illuminary. Illuminaries get their name from the Latin, illuminare, "to light up or illuminate." They are so named because of the bright paints, and often gold, used to decorate the writing and illustrations. Most illuminated pages were bound into books, which are sometimes also referred to as
codices (singular, codex).
Illuminaries were primarily made on parchment or vellum until Gutenburg's invention of the printing press automated the production of books, requiring the invention of paper. Parchment and vellum are disputed terms. Some people argue that the term parchment properly refers to materials derived from the skin of sheep or goats while vellum comes from calves. Furthermore, vellum refers specifically to skin which has been abraded with pumice. Despite this, most cataloguers use the terms interchangeably, referring to all the items in their collection printed on skin as either vellum or parchment without discrimination.
At any rate, parchment or vellum is made by soaking the pelt of a goat, sheep or calf in a lime solution to loosen the fur, which was then removed. While wet the animal skin was bound to a stretcher and scraped using a knife with a curved blade. Over a period of days, the skin was dampened, scraped and stretched further until the desired thinness had been achieved. Then the parchment or vellum was cut into the appropriate sized rectangles for making the book. Below is a picture of a skin being stretched to make parchment:
Once the parchment or vellum was shaped, the parchment was ruled. To accomplish this, the leaves were stacked and punched through with pin-prick holes, several sheets at once. These holes, near the edge of the page, indicated the spacing of columns, margins, and line height. After the holes were pricked, a straight edge was laid along them and ruling lines were drawn, usually with leadpoint or colored ink. Ruling lines helped the scribe to write evenly and were part of the design of the page.
The scribe wrote with a quill pen made from the feather of a goose or swan. The nib on the tip influenced the shape of the letters. A very common ink was iron gall ink. This ink was prepared by mixing ferrous sulfate with tannin, normally derived from oak galls or galls of other trees.
Once the words were written on the page, an artist would design and paint the illumination. The process begins by making an outline drawing with leadpoint or quill and ink. The areas where gold leaf would be applied were painted with a sticky substance such as bole (a refined red clay) or gum ammoniac (sap). The gold leaf was then applied and rubbed, to create a shiny surface. Finally, the illuminator applied paints for the rest of the drawing. Below is a picture of an illumination. Some writing can be seen around it:
Common pigments in the paints were:
Terre Verte (Green Earth), made from the minerals glauconite and celadonite. It was neutral yellow green to pale greenish gray to dark matte olive green.
Ultramarine, made from the precious stone lapis lazuli (it was more expensive than gold in the Middle Ages). It was a bright blue color.
Azurite, made from copper carbonate prepared by grinding the lump form, then washing to separate the color from impurities. It is dark blue.
Orpiment, made from naturally a naturally occurring arsenic sulfide. It ranges from a bright to dull, brownish yellow.
Lead White, made by suspending strips of lead above vinegar or urine in a vase, sealing it and burying it in a dung heap for several days. After a few days the artist scraped off the crust formation on the lead and ground it for use. (Yum--women used this for cosmetics too, even though it was highly toxic if ingested).
Red lead, made by heating white lead until the heat expels water and carbon dioxide from the crystals in the form of gas.
Lead-Tin Yellow, made by gently roasting white lead until lead monoxide is produced.
Verdigris, made by the corrosion of strips of copper with vinegar fumes. After the pigment was scraped from the plate, it was mixed with wine and allowed to thicken. The color produced ranges from green, green-blue to blue.
Vermillion, made from red mercuric sulphide obtained from cinnabar, the principle ore of mercury, or artificially by heating sulphur and mercury together. It is red.
Non-mineral based pigments include:
Lamp black, made from the soot produced from burning linseed or other oils, pitch, candles, or resin. It was also mixed with gum and used for ink.
Vine black, made from burning grapevine twigs.
Saffron, made from the dried stamens of Crocus plants which were infused with glaire or gum water. It is yellow.
These pigments were usually mixed with egg white to form a paint called tempera.
Once the writing and illuminating had been completed, the parchment sheets were folded into groups called gatherings. The gatherings were ordered in their proper sequence and sewn together onto cords or leather thongs that served as supports. Once the sewing was finished, the ends of the supports were laced through channels carved into the wooden boards that formed the front and back covers of the book. The binding was usually then covered in leather or a decorative fabric. Some bindings were decorated with the metal corner pieces or raised medallions that would protect the binding as it rested on a surface.
Why is it important to know all these details? Because in order to properly restore/conserve an illuminary, without doing further damage to it, it is necessary to identify what type of pigment was used in the illumination in order to avoid destructive chemical interactions. Because, if one knows that the most commonly used ink was oak gall, one will also recognize the inherent dangers that accompany the use of oak gall inks on skins. Because vellum and parchment have different requirements for restorative treatments than paper-based products.
These will be the topics of the next several posts.
The J. Paul Getty Museum. (2003). The Making of a Medieval Book. Available
http://www.getty.edu/art/exhibitions/making/
Baker, Amy. (2004). Common Medieval Pigments. The Cochineal. Available
http://www.ischool.utexas.edu/~cochinea/pdfs/a-baker-04-pigments.pdf
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