What is tempera paint?

What is tempera paint made of?

Traditional egg tempera is a mixture of raw pigment powder, distilled water, and a binding agent, typically egg yolk. The yolk acts as an emulsion, holding the pigment particles in suspension and allowing them to adhere to a surface once the water evaporates. Because the binder is organic, it begins to dry and harden almost immediately upon application, creating a tough, water-resistant film that does not yellow or darken significantly over time.

Modern commercial "tempera" found in schools is chemically distinct from this traditional medium. These are often water-based poster paints made with starch or cellulose binders rather than egg. While they are safe and easy to clean, they lack the archival longevity and optical depth of authentic egg tempera. Artists interested in the historical medium must source high-quality dry pigments and prepare their own emulsions fresh daily to achieve the best results.

How to prepare egg tempera paint

Creating tempera requires a methodical approach to ensure the correct consistency and adhesion. The process begins by separating the yolk from the white and removing the yolk sac, as the sac membrane can rot and ruin the painting. Once the yolk is punctured and drained into a jar, it is mixed with an equal part of water to create the binder.

1. Separate the egg yolk from the white carefully.
2. Roll the yolk on a paper towel to remove any clinging egg white.
3. Puncture the yolk sac and drain the liquid into a small container.
4. Mix the yolk with an equal amount of distilled water.
5. Add a small amount of this binder to your pigment powder until it reaches a creamy consistency.

Always prepare only what you need for a single session. Because the egg binder is perishable, it will spoil if left out, leading to unpleasant odors and potential mold growth on your canvas.

Best surfaces for tempera painting

Tempera requires a rigid support because the paint film is brittle and can crack if the surface flexes. Wood panels, particularly those made from birch or poplar, are the traditional standard. These panels must be prepared with several layers of gesso, a mixture of animal glue and chalk or gypsum, to create a smooth, absorbent, and bright white ground.

• Use seasoned, warp-resistant wood panels to prevent structural movement.
• Apply at least four to six layers of traditional gesso for a professional finish.
• Sand each layer of gesso thoroughly with fine-grit sandpaper to ensure a glass-like surface.
• Avoid using flexible supports like stretched canvas, as the paint will eventually flake off.

The gesso acts as a foundation that absorbs some of the moisture, allowing the paint to bond firmly to the panel. A well-prepared surface is essential for the longevity of the work and the ease of applying fine, delicate brushstrokes.

How to paint with tempera

Painting with tempera is a process of building up color through thin, translucent layers called glazes. Because the paint dries almost instantly, you cannot blend colors on the surface like you would with oil paint. Instead, artists use a technique called cross-hatching, where tiny, overlapping strokes of color are layered to create the illusion of depth, volume, and smooth transitions.

1. Sketch your composition lightly onto the gessoed panel.
2. Apply thin, watery washes to establish the base values of the image.
3. Use small, sable-hair brushes to apply short, rhythmic strokes.
4. Build up highlights and shadows by layering increasingly opaque colors.
5. Allow each layer to dry completely before applying the next to avoid lifting the previous paint.

This methodical layering process is time-consuming, but it creates a unique luminosity that is impossible to replicate with other mediums. The final result is a matte, jewel-like surface that remains stable for centuries.

Common mistakes when using tempera

One of the most frequent errors for beginners is attempting to apply the paint too thickly. Tempera is designed for thin applications; if the layer is too heavy, the paint will crack as it dries and loses its flexibility. Another common mistake is failing to properly clean brushes, as the egg binder can harden quickly and permanently ruin expensive natural hair bristles.

• Do not use thick, impasto-style brushstrokes, as they will cause the paint to flake.
• Avoid adding too much water to the pigment, which can weaken the paint film and cause it to dust off.
• Keep a jar of water nearby to rinse brushes immediately after every few strokes.
• Never use synthetic brushes that are too stiff, as they can leave visible, unsightly drag marks in the delicate paint layers.

By adhering to these technical constraints, artists can master the precise, disciplined beauty of this ancient medium. Patience and a steady hand are the most important tools in the tempera painter's kit.