The binding properties of the egg were already known by artists in ancient Egypt, Greece and Rome, but it wasn’t until Middle Ages that egg tempera became the primary painting medium. In 14th century, in most European countries egg was used to paint on parchment, panels and even on walls. Throughout the 15th century Italy, most paintings on panel were still egg tempera paintings, although in the second half of the century oil has started to gradually replace it, first as an additive to egg emulsions and then as a binding medium in its own right.
All parts of the egg had their usage both in kitchens and in art studios. Egg white was used as varnish or as binder to create watercolor or gouache paint (typically mixed with gum arabic, as by itself it would give a very rigid film) for drawing on toned paper and painting on parchment (illuminated manuscripts). Egg yolk (either alone or with additives) was used to paint on panels, grounded with gypsum or chalk.
HOW TO PAINT ON PANEL.
[…] you must always temper your colors with yolk of egg, and get them tempered thoroughly—always as much yolk as the color which you are tempering. The third is that the colors want to be more choice, and well worked up, like water.
The craftsman’s handbook by Cennini, Cennino, active 15th century; translated by Thompson, Daniel Varney, 1902- ed
Artist painting probably in egg tempera using a brush and premixed colors contained in mussel shells, and an assistant grinding colors on the stone.
How to make egg tempera paint
§ 82. Painting in Tempera.
[…] They then mixed the colours they were going to use with the yolk of an egg or tempera,? of the following kind. They whisked up an egg and shredded into it a tender branch of a fig tree, in order that the milk of this with the egg should make the tempera of the colours, which after being mixed with this medium were ready for use.
They chose for these panels mineral colours of which some are made by the chemists and some found in the mines. And for this kind of work all pigments are good, except the white used for work on walls made with lime, for that is too strong. In this manner their works and their pictures are executed, and this they call colouring in tempera. […]
Giorgio Vasari (1511-1574), Vasari on technique; being the introduction to the three arts of design, architecture, sculpture and painting, prefixed to the Lives of the most excellent painters, sculptors, and architects
The process of pigment grinding can be seen in the background
XXXII. [270] How yolk of egg is prepared. — Orpiment [this pigment is very toxic and you should not use it, but this process of tempering with egg yolk can be applied to many other pigments] is ground and prepared with the yolk of egg in the following manner, and the yolk of egg is thus prepared :
—Take the yolk in the middle of your hand, and prick it with a thorn or a needle, and, putting your finger upon it, press it out, and receive it in a vase ; and, adding a drop of water to it, mix it with the orpiment. If you mix oil with it, it will never dry. Mix it therefore with yolk of egg.
Manuscripts of Jean Le Bègue, 1368–1457, Mary P. Merrifield, Medieval and Renaissance treatises on the arts of painting : original texts with English translations
Let’s do some Alchemy!
Basic egg tempera ingredients
OVUM
Since the very early days of our civilization eggs are used in a variety of fields. In art, each part of the egg has its particular uses:
- Egg yolk is mainly used as binder to work on panels and to make emulsions
- Egg white (also know as glair) is used as binder to paint on parchment and paper, it creates a very hard and shiny veil and thus sometimes white of the egg was used as varnish
- Egg shells, rich with calcium, were also powdered and used as an additive to colors or even as pure pigment.
AQUA
Clean water, typically rain or spring water was used. We will use distilled water.
ACETUM
White wine vinegar (or white wine) was used as a preservative in recipes including organic ingredients, such as egg, hide glue, oak galls and other ingredients of plant and animal origin.
Its main purpose was to increase shelf life preventing putrefaction and mold formation, but sometimes vinegar and white wine are said to improve brilliance and flow of the paint.
Alternative preservatives include acetic acid, cloves or lavender essential oils or modern biocides.
Additional ingredients:
The recipes of egg tempera are infinite. Its emulsifying properties make it possible to mix it with all usual additives of oil and water based mediums.
- Egg white: adding whipped egg white will make the paint film glossier and harder
- Fig sap: in Italian called latte di fico, “milk of fig tree” appears in recipes including the whole egg (youlk and white together) presumably it blended the white and yolk together, and reduced any tendency to brittleness which might have resulted from the use of so large a proportion of egg-white in the medium.
- Gum arabic can effect adhesive properties and viscosity of the medium
- Ox Gall: improves the flow of egg tempera and watercolor paint, helps egg tempera adhere to gold and other metallic foils
With additions of oils and resins one can create a different medium called tempera-grassa (fat tempera emulsion):
- Oils: linseed, nut or poppy oils, either raw or cooked, standoil and sun thickened oils
- Resins: Damar varnish, Mastic of Chios etc.
Let’s start with a simple and most reliable egg tempera medium: plain egg yolk mixed only with water and afew drops of a preservative.
Recipe:
Basic egg tempera paint recipe
Ingredients:
- Egg
- Distilled water
- Vinegar
- Dry color pigment
Step 1: Prepare the egg yolk
Separate egg yolk from white and pour it out of its membrane to a clean container
Step 2: Dissolve the yolk
Egg yolk tends to be quite dense you might want to add a little water to it but not more than the volume of the yolk itself.
Step 3: Add a preservative:
5 drops of wine vinegar. If you use white wine, you should add a little more, but reduce the amount of water you add accordingly.
Step 4: ADD the pigment:
Prior to be mixed with any water-soluble binder, you should grind the pigment in distilled water (the amount of water will change depending on the pigment properties). This way you can store the pigment ground in water for as long as you want and use it (temper it) with any water based medium you like (gum, egg yolk or white, casein, glue and acrylic) or even use it for fresco painting.
The proportions of medium and pigment paste should be nearly 1:1, but in practice every pigment requires a slightly different amount of binder.
