Understanding Pigment Binder Ratios: Essential Tips for Oil Painters

When creating oil paintings, artists strive to balance aesthetics and durability. One critical factor influencing these goals is the pigment binder ratios (also known as pigment-to-binder ratio or P/B) or pigment volume concentration (PVC) of the paint. These terms describe the proportion of pigment relative to the oil binder, which plays a vital role in the paint’s drying process, stability, and long-term preservation.

This article examines the findings from recent scientific studies on how different P/B ratios affect oil paints. It explains technical terms, provides evidence-based insights, and offers practical recommendations to help artists make informed decisions about their materials.

Understanding Pigment Binder Ratios and PVC

Pigment-to-Binder Ratio (P/B)

This ratio indicates the amount of pigment compared to the binder (often linseed oil) in a paint formulation. A high P/B ratio means more pigment and less binder, while a low P/B ratio implies the opposite.

Pigment Volume Concentration (PVC)

PVC measures the proportion of pigment in the paint relative to the total volume of solids. When PVC is low, the paint has a higher binder content, making it glossy and smooth. High PVC creates a matte finish but can lead to surface vulnerabilities.

Effects of Low and High Pigment Volume Concentrations

Low PVC: Glossy, Flexible, but Susceptible to Aging

Paints with low PVCs—characterized by high oil content—tend to have a glossy and smooth finish. They also offer flexibility, which reduces the likelihood of cracking as the paint film ages. However, these paints are more susceptible to yellowing and oxidative degradation because the excess binder remains exposed to environmental factors for longer periods.

For example, studies like those by Sotiropoulou et al. (2018) show that higher binder ratios exacerbate oxidative degradation in oil-based paints exposed to fluctuating climates. Similarly, Modugno et al. (2019) highlight how high humidity accelerates the hydrolysis of the oil binder in low-PVC formulations, leading to faster deterioration.