Lamp Black Oil Paint: Drying Time, Additives, and Curing for Professional Artists

Understanding the materials we use is crucial for artists who want to create lasting works of art. The study of how pigments and other additives affect the drying process of oil paints has a direct impact on the techniques and outcomes of our artwork. A recent study, Unravelling the Effect of Carbon Black in the Autoxidation Mechanism of Polyunsaturated Oils, delves into the intricate effects of carbon black, a commonly used pigment, on the curing of oil paints. This review aims to summarize the study’s key findings and provide practical insights for artists, especially those using carbon black pigments like lamp black.

Lamp Black Oil Paint and Its Effect on Drying Time

Carbon black, particularly in the form of lamp black, is known for its deep, rich black color. However, it significantly affects the drying time of oil paints. The study confirms that carbon black slows down the autoxidation process in linseed oil, the primary binder in most oil paints. This delay is due to carbon black’s antioxidant properties, which inhibit the formation of peroxides, critical components in the drying and hardening process of oils.

For artists, this means that while carbon black provides intense color saturation, it may extend the drying time of the paint, making it important to account for longer waiting periods between layers or consider the use of drying agents.

How Zinc Stearate and Aluminium Stearate Affect Oil Paint Curing

The study also investigated the effects of common additives—aluminum stearate and zinc stearate—on the curing of carbon black oil paints. These metal stearates are frequently added to oil paint formulations to enhance pigment dispersion and adjust the paint’s body and texture. Interestingly, both additives accelerated the initial stages of the curing process. Zinc stearate, in particular, significantly increased the formation of peroxides in the first month of drying, suggesting a quicker but more intense drying phase. After this period, the curing process slowed, with active radicals and peroxides remaining even after 12 months.

Artists using carbon black paints with these additives should be aware of these accelerated drying phases and adjust their techniques accordingly, perhaps allowing for shorter intervals between applications but anticipating slower full curing times in the long term.

Abbreviations used in the Study

• CBLO—Carbon black in linseed oil
• CBLOAl—Carbon black in linseed oil with aluminum stearate
• CBLOZn—Carbon black in linseed oil with zinc stearate
• LWLO—Lead white in linseed oil
• UBLO—Ultramarine blue in linseed oil

Comparing Lamp Black to Other Pigments in Oil Paint Drying

The study contrasts the effects of carbon black with other pigments, including lead white and ultramarine blue. Lead white, a known drying agent, accelerates the curing process, while ultramarine blue, like carbon black, slows it down. The systematic mass loss in carbon black-based paints, observed over time, was attributed to the evaporation of low molecular weight degradation products. This was not found in lead white paints, where fatty acids bind with lead to form stable metal soaps, preventing significant evaporation.