Pigments are insoluble chemicals, whether organic or inorganic, that are used to provide colour to different products on the EU market. They comprise several chemicals, a number of which are nanomaterials. The size of the pigment particles can play an important role in the properties of these chemicals.

Nanomaterials, such as colloidal gold particles for staining glass have been used for hundreds of years, and can be found in the stained glass windows of many historical buildings throughout Europe. Nanomaterial pigments can be found in a number of different products, paints, coatings, printing inks, and cosmetics.

The characterisation of which pigments are nanomaterials, represents an important scientific and regulatory challenge, as is the case for nanomaterials in general. The placement of pigments, including nanomaterial pigments, on the EU market is governed by different regulations, including the REACH regulation, and where relevant, EU regulations on cosmetic products and foods, among others.