Natural And Manufactured Pigments

“Natural” in general and when we talk about pigments is becoming a popular trend, with many artists choosing them because they’re perceived as fresh, non-toxic, and safe. However, this connection between “natural” and safety can be misleading. The term “natural” refers to the source or method of production, not necessarily to the safety of the pigment. In contrast, manufactured pigments are made through synthetic processes, but both types can vary in their properties, including toxicity. Let’s explore the differences and current trends in the paint-making industry.

Natural pigments are sourced from plants (e.g., indigo), minerals (e.g., ochre), or animals (e.g., ivory black). However, due to ethical concerns, the use of animal-based pigments is no longer allowed today. For instance, Indian yellow, once made from cow’s urine fed on mango leaves, and ivory black, made from burned animal bones, are no longer in use. Many plant-based pigments also have poor lightfastness, making them less popular in modern art. Examples include alizarin crimson, derived from madder plant roots, and indigo, sourced from the Indigofera plant, both of which are rarely used today.

Mineral pigments remain widely used today, offering a broad range of colours and hues. These pigments typically have the highest lightfastness and are often opaque, making them ideal for oil painting. Many earth tones come from natural clays, with colours ranging from yellow to maroon, brown to green, and blue-grey. The specific location of extraction and the particle size influence the pigment’s hue and transparency.

Due to their insolubility in water, most mineral pigments also produce beautiful natural granulation in watercolour. For more vibrant and intense colours, pigments like cobalt and cadmium are particularly prized, especially in oil and acrylic paints, where their brightness and strength stand out.

For artists, there are two main drawbacks to using natural pigments. First, because minerals are unique and influenced by the natural environment, the colours of the same pigment can vary depending on the source and change from year to year. This makes the industrial production of paints inconsistent and unpredictable. Second, some minerals may contain impurities, such as lead, which can pose potential health risks.

These factors contributed to the gradual shift from natural to synthetic pigments. Lapis lazuli was replaced by ultramarine (PB29), while natural yellow and red ochres, cobalt, and cadmium were supplanted by synthetic ones.

Additionally, artists’ paints account for less than 2% of global pigment production, and many pigments have become extinct as they are no longer used in industries like automotive or plastics. Quinacridone Gold (PO49), Anthraquinone Red (PR89), Nitroso Green (PG8), Nickel Azo Yellow (PG10) and many other have disappeared or are disappearing from the artists’ palettes.

Instead, we are seeing an increasing use of synthetic organic pigments developed in laboratories, which offer stronger tinting power and are more widely used in industrial applications. As a result, more new pigments are becoming available for artists’ paints. Organic pigments are favored by manufacturers due to their predictable production process. However, they often lack the opacity that oil painters prefer, although this works well for watercolours. Additionally, many organic pigments are relatively new and haven’t been tested over long periods. This means their lightfastness is not the only concern—chemical stability over time is also uncertain.

For example, phthalocyanine pigments were once regarded as permanent and among the most lightfast available. However, recent testing has shown that their lightfastness can vary significantly depending on factors like mass tone, transparency, or whether they are mixed with white, all of which can affect the pigment’s durability over time.

There is no straightforward answer to which pigments to choose, but generally speaking, I’d recommend using mineral or inorganic pigments for oil paints and organic pigments for glazing techniques and watercolours.