Why is Gouache Paint Opaque and How Does it Compare to Watercolors?

Gouache, a versatile and richly pigmented paint, is often used in art and design for its unique properties. Unlike watercolors, gouache is known for its opacity, which sets it apart. In this article, we will delve into why gouache is opaque, compare it to watercolors, and explore the different brands and methods of creating this vibrant medium.

The Science Behind Gouache's Opacity

The primary reason for gouache's opacity is the addition of a binding agent and specific pigments. While watercolors are transparent, gouache is made primarily from dry pigments bound together with a larger proportion of gum arabic, a natural binder. Some gouache paints also contain calcium carbonate, which further enhances their opaque quality.

The process of making gouache paint involves combining these pigments with a higher amount of binder, which results in a paste that is more water-resistant and less likely to become translucent even when added to water. This paste is then applied to paper, resulting in a matte finish with rich, intense color.

Comparison with Watercolors

Watercolors, on the other hand, rely on their transparency to maintain clarity and luminosity. When watercolors are applied to paper, they quickly spread and blend, revealing the underlying white of the paper, which gives the final artwork its light, airy appearance. This is a significant difference from gouache, which maintains its opaque nature regardless of the quantity of water added.

While some artists choose to use watercolors due to their transparency, others, like myself, prefer the matte quality and intense color of gouache. The choice often depends on the desired effect and the specific needs of the project.

Brand Differences and Opacity

Not all brands of gouache are equally opaque. Typically, the most expensive brands are the ones that offer the greatest opacity, with Schmincke Horadam Gouache being one of the top choices. The high quality of these brands is due to the proprietary ingredients used in their formulations, which provide a richer, more consistent opacity.

Other brands may offer varying levels of opacity, which can affect the overall quality and versatility of the paint. While the binder and pigment content are key factors, the specific composition can vary, leading to subtle differences in texture and color.

Conclusion

Gouache paint is opaque due to the inclusion of specific binders and pigments, such as calcium carbonate, which enhance its matte quality and intensity. This is in stark contrast to watercolors, which maintain a transparent appearance.

Understanding the properties of gouache and watercolors can help artists choose the right medium for their projects. Whether you prefer the luminous clarity of watercolors or the rich, opaque finish of gouache, both mediums offer unique advantages for creating beautiful works of art.