Are earth pigments lightfast?

The lightfastness of earth pigments can vary depending on the specific pigment and its formulation. However, Iron Oxides are lightfast and do not change colour or react with binders used by artists.

Lightfastness refers to a pigment's ability to resist fading or changing colour when exposed to light over time. Most earth pigments are relatively lightfast and can be used in art or decorative applications that will be exposed to sunlight for extended periods. It should be noted that copper carbonate pigments, particularly the historic blue bices, change colour when used with oil mediums, turning green as they react to the acid in the oil.

However, other earth pigments may be less light and can fade or change colour over time if exposed to light. To ensure the lightfastness of earth pigments in your artwork or decorative projects, it's crucial to use high-quality pigments rigorously tested for lightfastness. This will give you the confidence that your work will stand the test of time and that you will take proper care to protect your job from prolonged exposure to light.

Which Earth Pigments Are Most Lightfast?

There is no definitive list of most lightfast earth pigments, as the lightfastness of a pigment can vary significantly. It depends on several factors, including the specific pigment, its formulation, and the conditions under which it is used. This variability underscores the need for artists to research and understand the lightfastness of their pigments.

However, some earth pigments that are generally considered to be relatively lightfast include:

Iron oxides, such as red iron oxide (also known as hematite), yellow iron oxide (also known as limonite), and brown iron oxide (also known as goethite).

Titanium dioxide

Ultramarine blue (made from the mineral lazurite)

Earth pigments that are treated or formulated with lightfast resins or binders.

It's important to note that even lightfast earth pigments can fade or change colour over time if exposed to intense or prolonged light. Therefore, it's always a good idea to take proper care to protect your artwork or decorative projects from exposure to light. This practice is crucial in preserving the beauty and integrity of your work over time.