At its most basic, artists’ paint consist of three components: a binder to form the paint layer and stick it to the ground, diluent to control the viscosity of the paint (which normally evaporates soon after application), and pigment. The binder determines the paint’s properties, both during application and its drying and longevity.
For example, in oil paints the binder is a drying oil such as linseed, which polymerises with oxygen from the air to form a robust paint layer, diluents are usually organic solvents such as turpentine and its substitutes, and there’s a vast range of different pigments.
At some stage in the distant past, our ancestors discovered that processing some natural products created glues. The raw materials either came from boiling animal bones, hide, and other offal, or from natural exudates of plants. These proved to be suitable as the binder for paints. Being ancient in origin, different combinations of binder, pigment, and other substances developed, and these have left a confusion of terms, including glue tempera, and distemper.
These represent a spectrum of paints, ranging from those in which only glue and pigment are used, to others which also incorporate substantial amounts of powdered chalk or lime, and are related to whitewash. I here use the term glue tempera to include them all, as glue is the essential binder, and the addition of chalk or lime primarily makes them opaque, and contributes relatively little to the mechanical properties of the paint layer.
Glue tempera was used in antiquity, and outside Europe remains in widespread use. It has proved to suffer several limitations, including:
- ‘Drying light’, undergoing a marked colour change as the paint dries, reducing the intensity of chroma.
- Mechanical fragility of the paint layer, making it particularly susceptible to abrasion and cracking.
- Solution on re-wetting, so it can easily be reworked like watercolour, but is unsuitable for any unintended exposure to water or damp. Hardening of the glue binder is not the result of a stable polymerisation, as with oil paints, and can readily be reversed.
- Relatively poor protection of light-sensitive pigments, commonly leading to fading of colour over time.
In the early Renaissance, some artists used glue tempera extensively, and with great success, although surviving works have not aged as well as those painted using egg tempera or oils.
Dieric Bouts’ The Entombment from about 1450 was painted using glue tempera on linen. Although it’s now well over half a millennium old, and its colours have sadly faded, it’s well worth seeking out when you next visit The National Gallery in London.
Botticelli’s Map of Hell from 1480-90 uses an unusual combination of glue tempera with silverpoint and ink. Silverpoint draws with silver metal wire, and lays down grey lines which appear faint at first but deepen in tone with time.
In the south of Europe, Andrea Mantegna was one of its great exponents, as shown in his marvellous glue tempera and gold painting of A Sibyl and a Prophet from about 1495.
Some artists, such as Joris Hoefnagel, continued to use these ancient techniques at the end of the sixteenth century, as shown in this painting of Diana and Actaeon from 1597. This is finely executed in glue tempera and gold on vellum.
With the widespread adoption of oil paint, glue tempera almost disappeared until it was revived at the end of the eighteenth century by William Blake. He wanted to return to what he considered was traditional “tempera”, but instead of using an egg binder to make egg tempera, he painted in glue tempera.
Blake’s Adoration of the Kings from 1799 shows the dulling of colour resulting from fading pigments, and the fine cracking caused by his use of stretched canvas as the support.
Some of Blake’s glue tempera paintings have survived in much better condition: The Christ Child Asleep on the Cross, or Our Lady Adoring the Infant Jesus Asleep on the Cross from 1799-1800 has fared better, retaining much of its original colour.
Blake’s Virgin and Child in Egypt from 1810 show the fine modelling he was able to achieve in the figures.
Overall, though, the condition of Blake’s glue tempera paintings isn’t good. It has been suggested that some of the variation is attributable to different sources of glue, which is clearly of major importance. For a long time, glues provided for this and similar purposes in painting have been referred to as ‘rabbit skin glue’, but in reality the great majority are derived from a wide range of animal products, often in uncontrolled conditions.
After Blake, the medium fell into obscurity again until later in the nineteenth century, when it was revived by movements which attempted to return to techniques of the past, most prominently the Nabis in France.