Step into the luminous world of egg tempera, a painting technique reaching back through centuries, renowned for its jewel-like clarity and remarkable endurance. Unlike the more familiar oils or acrylics, tempera relies on the humble egg yolk as its binder, creating a unique painting experience that is both demanding and deeply rewarding. It’s a medium that doesn’t allow for easy blending or impulsive reworking; instead, it calls for patience, precision, and a deep understanding of materials. Mastering tempera connects the artist directly to a lineage stretching from ancient Egypt through the Byzantine masters and the titans of the early Italian Renaissance like Botticelli and Fra Angelico.
The Golden Binder: Preparing the Egg Yolk
The magic begins with a fresh hen’s egg. The yolk is the star, providing the emulsion that holds the pigment particles together and adheres them to the painting surface. Preparing it correctly is fundamental. First, carefully crack the egg and separate the yolk from the white. Letting the yolk roll gently onto a paper towel helps absorb clinging albumen (egg white), which can cause cracking if included in the paint film. The crucial step is removing the vitelline membrane, the thin sac enclosing the yolk. Gently pierce the membrane with a pin or the tip of a knife and allow the liquid yolk to flow into a clean container – typically a small glass jar or dish. Discard the membrane; only the pure, liquid yolk is used.
Some practitioners add a little distilled water to the yolk, perhaps a teaspoon or so, to adjust the viscosity and working properties. Others might add a drop of vinegar or clove oil, acting as a mild preservative to slightly extend the working life of the paint for the day, though tempera is best made fresh each painting session. The yolk itself is a natural emulsion of oil and water (lecithin), providing both adhesive strength and a unique optical quality. It dries quickly by evaporation, forming a tough, water-resistant film once fully cured, which can take several months.
From Earth and Stone: Preparing Pigments
Traditionally, tempera artists worked with dry pigments, finely ground powders derived from minerals, earths, and sometimes organic sources. Think of ochres, umbers, siennas dug from the ground, vibrant blues from lapis lazuli, greens from malachite, or reds from cinnabar. Today, while many traditional pigments are still available, artists also have access to modern synthetic pigments offering greater lightfastness and a wider chromatic range. Regardless of the source, the pigment must be incredibly fine.
Preparation involves mixing the dry powder with the prepared yolk binder. This isn’t just a simple stir; it’s a process called dispersion. A small amount of pigment powder is placed on a hard, non-porous surface – a glass slab or marble tile is ideal. A few drops of distilled water are often added first to create a stiff paste, working the pigment thoroughly with a palette knife or, more traditionally, a glass muller. This initial wetting ensures each pigment particle is surrounded by liquid, preventing clumping. Once a smooth paste is achieved, the prepared egg yolk binder is gradually added, mixing continuously with the muller using a circular or figure-eight motion. The goal is to coat every tiny pigment particle with the yolk emulsion. The final consistency should be creamy, flowing smoothly from the brush but not watery. Each pigment requires slightly different amounts of binder due to varying particle sizes and oil absorption rates – experience is the best guide here.
Be mindful that many traditional pigments are toxic (e.g., lead whites, cadmium reds, arsenic oranges). Always handle dry pigments with care, avoid inhalation by wearing a dust mask, and practice good studio hygiene. Never eat, drink, or smoke while handling pigments. Keep them securely stored and away from children or pets.
The Groundwork: Preparing the Panel
Egg tempera demands a rigid, absorbent support. Flexible canvas is unsuitable because the dried tempera film is relatively brittle and prone to cracking if flexed. Historically, well-seasoned wood panels, particularly poplar in Renaissance Italy, were the standard. Today, artists use solid wood panels or stable engineered boards like high-density hardboard (Masonite) or Baltic birch plywood.
The crucial element is the ground: the surface layer applied to the panel that receives the paint. Traditional tempera requires a genuine gesso ground, which is quite different from modern acrylic ‘gesso’. True gesso is made from animal collagen glue (typically rabbit skin glue) and an inert white pigment or filler, such as gypsum (gesso sottile) or chalk (calcium carbonate). Preparing it is laborious. The glue is soaked, heated gently in a double boiler (never boiled), and then mixed with the warmed filler. Multiple thin layers – sometimes ten or more – are brushed onto the panel, often alternating directions. Each layer must dry before the next is applied. Once built up, the gesso surface is meticulously scraped and sanded to an ivory-smooth, highly absorbent finish. This luminous white ground reflects light back through the translucent tempera layers, contributing significantly to the painting’s characteristic glow.
Modern Alternatives
While traditional gesso offers unparalleled luminosity and absorption, its preparation is time-consuming and sensitive to humidity. Some contemporary tempera artists use modern alternatives like acrylic dispersion grounds or specialized panels prepared for tempera, though these may subtly alter the paint handling and final appearance compared to a true gesso surface.
Application: Weaving with Colour
Painting with egg tempera is fundamentally different from oil or acrylic painting. The paint dries almost instantly as the water content evaporates, making smooth blending impossible. Instead, form and colour are built up through the precise application of countless small, deliberate brushstrokes.
Hatching and Cross-Hatching: This is the quintessential tempera technique. Short, fine, parallel lines (hatching) are applied, often following the form of the object being depicted. Subsequent layers of hatching can be overlaid, sometimes at angles (cross-hatching), to deepen tones, model form, and create optical colour mixtures. Imagine weaving threads of colour together. Fine-pointed sable or synthetic brushes are typically used.
Layering and Glazing: Because the paint dries so quickly, layers can be built up rapidly without disturbing underlying paint. Tempera is inherently semi-translucent. Thin, diluted applications of colour (glazes) can be applied over underlying layers to modify hues subtly and enhance luminosity. The light travels through these layers, reflects off the white gesso ground, and bounces back to the viewer’s eye, creating a depth and glow unique to the medium.
Stippling: Applying tiny dots of colour can also be used, particularly for subtle textures or transitions, though hatching is more common for general modelling.
The process demands foresight. Colours cannot be easily mixed on the panel itself; variations in tone and hue are achieved primarily through layering and the optical mixing of adjacent or overlaid strokes. The artist must plan carefully, building from light to dark or establishing mid-tones first. The quick drying time forces a methodical, rhythmic approach.
A well-executed egg tempera painting possesses remarkable archival stability. When applied correctly to a properly prepared rigid support, the colours remain vibrant for centuries. The quick-drying nature forms a tough, insoluble film resistant to yellowing, unlike traditional oil paints. Many Renaissance tempera masterpieces look astonishingly fresh even today.
Egg tempera is not a medium for the impatient, but for those willing to embrace its disciplines, it offers unparalleled luminosity and a direct connection to painting history. The meticulous preparation of yolk, pigment, and panel, combined with the precise, layered application, results in works that glow with an inner light. It’s a testament to the enduring power of simple, natural materials transformed by artistic skill and dedication.
