Oil, acrylic, and ink are chemically doomed

Why Oils, Acrylics, and Inks Fail — Even Under Ideal Conditions

No matter how carefully you store them, traditional painting mediums like oil, acrylic, and ink are chemically unstable over long time spans. Their breakdown is not a matter of if — but when.

Oil Paint

Oil paint begins deteriorating the moment it’s exposed to air. That’s not a flaw — it’s how it cures. Linseed and other drying oils polymerize through oxidation. But that same oxidative process continues quietly for decades and centuries, causing the paint film to:

• Yellow due to continued oxidative cross-linking.

• Brittle with age, especially in cooler or drier environments.

• Crack and flake due to expansion and contraction of the substrate beneath it.

Even in climate-controlled museum conditions, oil paintings are known to darken, develop craquelure, and separate from their supports. These are inherent chemical liabilities — not fixable through framing or glass.

Acrylic Paint

Acrylics are more flexible at first, but that plasticity becomes their weakness. The polymer emulsion never fully hardens the way egg tempera or oil does. Over time:

• Humidity causes softening, dust adhesion, and potential mold growth.

• Heat causes shrinking and crazing — a network of fine cracks in the paint film.

• Plasticizers migrate out of the paint over decades, making the film chalky or sticky depending on environment.

Acrylics are essentially industrial plastics. While designed to be durable, they were never engineered for permanence over centuries, let alone millennia.

Inks

Most inks — whether dye-based, pigment-based, or archival — are designed for readability, not resilience. Unless kept in total darkness:

• Dyes photodegrade rapidly under UV light.

• Pigmented inks may last longer, but still slowly lose vibrancy through exposure to ambient light and ozone.

• Binder layers (like gum arabic or shellac) can become brittle or powdery over time.

Even so-called archival inks are "archival" by institutional standards (typically 100–200 years) — not geological ones.

In Contrast: Egg Tempera in a Controlled Atmosphere

Egg tempera doesn’t suffer from these vulnerabilities. Once cured, its binder is insoluble, crystalline, and nearly impervious to humidity. And when sealed in a low-oxygen, UV-shielded ecosphere, you’ve removed the three main decay agents — oxygen, UV, and moisture.

There is no yellowing. No softening. No pigment migration. No chemical instability.

In short:
Oil will yellow and crack. Acrylic will warp and split. Ink will fade.
Egg tempera, sealed in an inert atmosphere, will not.