Egg Tempera White: Choosing the Right White Pigment for Stability and Performance

White pigments do more than raise value. In tempera, they also shape opacity, surface feel, absorbency, and long-term change. Choosing the right egg tempera white is therefore a structural and aesthetic decision. This study asks a direct question: how do historic white tempera systems react in sulfur-dioxide-rich air? For today’s tempera painters, that is useful because egg tempera white passages often dominate grounds, flesh mixtures, highlights, and pale passages.

Rivas and coauthors tested fourteen tempera mock-ups made with one white pigment and one protein binder. The pigments were calcite, Bianco di San Giovanni (lime white), gypsum, and lead white. The binders were egg yolk and rabbit skin glue. The team then exposed the samples to accelerated sulfur-dioxide aging and tracked color, gloss, reflectance, roughness, mineral changes, and surface deposits (Rivas et al. 2025, pp. 3–6).

The main lesson is not that one white is always best. Instead, each white followed its own reaction path. Meanwhile, binder choice still mattered. In these white systems, binder choice affected visible change and surface texture more than it affected the total amount of sulfur salts formed (Rivas et al. 2025, pp. 15–17).

Why Egg Tempera White Choice Matters to Artists

Egg tempera painters often choose whites for handling and appearance. However, this paper shows that white choice is also a conservation choice. That matters most for works kept in cities, shown in old buildings, or stored where moisture and polluted air can collect.

The paper is also useful because the tested whites are not chemically alike. Calcite and Bianco di San Giovanni are carbonate-rich whites. Gypsum is a sulfate white. Lead white is a basic lead carbonate white. They may all look white in use. However, they do not age in the same way when sulfur pollution is present (Rivas et al. 2025, pp. 3–4, 10–11).

For egg tempera, that point is important. Egg tempera films are thin and lean. Therefore, small changes in roughness or reflectance can change how flesh, light, and soft scumbles read to the eye.