Pigments


 

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Oyster shells with traces of pigments, London 13th century - Guildhall Art Gallery, case 23

For more information on the shells  see Museum of London entry here





Paint

To make paints, the medieval illuminator needed pigments for the color and a binder to bind the pigment to the working surface. On parchment and for books, only oil-free binders such as glair and gum Arabic were used; paintings and icons featured the use of egg yolks in tempera painting.

Pigments

Pigments provide the color for paints and can be made from a variety of products such as minerals, soil, chalk, animal matter and plants. To prepare pigments for paints, the material would be ground into a fine powder and then mixed with water and a binder. The proportions of this mixture needed to be carefully balanced because too much binder made the paint sticky and would glue pages together, while too little binder would cause the paint to crackle and peel off of the parchment or paper. The proper mixture of paints required experience and knowledge of the various ingredients:

         Pigments from minerals, soil, etc.

clay (brown), chalk (white, grey), ockre (from yellow to darkbrown), Lapislazupli (blue), auripigment (yellowgold, poisenou), azurit (pale blue), malachit (green)

         Pigments from chemial reactions

leadwhite (white, highly poisenous), minium (red-orange, by heating leadwhite to 480 degrees Celsius, just as poisenous as leadwhite), verdigris (oxidized copper, from yellow-green to brilliant turquoise, eats parchment and paper!), zinnober (mercury with sulfur, red color)

         Pigments from plants

saffron (yellow-gold), folium (lat. Chrozophora tintoria Iuss.; red to purple), woad and indigo (blue), several plants for green sap, including parsley, cabbage, leeks, etc.

         Pigments from animal matter

Purpursnail Murex brandaris or Murex trunculus (purple; it was incredibly expensive and sometimes used to dye the parchment for extraordinary codices various shades of purple), dried lice (Kermes Vermilio Planch.) mixed with alum (red), gall (a light but brilliant yellow, usually combined with saffron or auripigment)

 

Binders

Various types of binders are used depending on the type of project, the desired effect and the available materials.

         Glair. Whip egg white to a froth, and then let it sit. Strain the liquid into a separate container and keep in the refrigerator. Glair can also be used for gold leafing.

        Gum Arabic. Take gum Arabic clumps and dissolve in hot water, then strain through a fine mesh to remove impurities. (Since it's a tree sap, it might contain dirt, etc.)

        Egg yolk. Break the egg and remove the egg white. Carefully hold the egg yolk in one hand and gently pinch the yolk sack between your fingers. Use a sharp knife to cut into the sack and pour the yolk into a container. This needs to be used quickly because it can't be reconstituted once it separates.

 

The following recipes for making a gum Arabic solution and glair are taken from the book The Art of Limning:

 

To make gum water to temper colors withal. Take clean water and do it in a vessel and put thereto a portion of gum Arabic and let it stand until the gum be well dissolved and molten in the water, but look it not be over thick of gum then will the color fade and fall off, therefore keep a mean and temper your colors therewith such as it serves best. Note the best gum is clear and brittle that in stamping it, it becomes powder easily without cleaving together.

To make glair for like purpose. Take the white of new laid eggs, as many as you think good, and strain them through a linen cloth to take out the cock treadings, then put them in a dish and ring them through a sponge or a white woolen cloth until they be as thin as water, then wash the sponge or cloth and dry it. And put the glair to {thuse} aforesaid in a stone pot or a glass fast stopped and spend it as soon as you can, for it will not keep above three days, but it will have an ill favor, except they be ordered as follows.

 

Gum Arabic might, after a time, grow some mold, but this does not effect its usability. Glair will eventually start to rot unless preservatives such as arsenic, clove or vinegar are added to the mix.