Natural earth and pure mineral pigments, vegetable pigments
Until the 19th century, when modern synthetic pigments were introduced, many of the colors used for painting were finely-ground minerals. Their color was determined by the metals embedded in minerals, and this is also true for many modern synthetic colors.
Pigments can be classified into four macro-categories:
- Natural inorganic pigments: metals and rare earth pigments extracted from natural mineral deposits. With few exceptions, these natural inorganic pigments are no longer used as expensive to extract and because they do not produce adequate color consistency.
- Synthetic inorganic pigments: prepared through industrial processes from raw materials, they represent 80% of the world’s pigments production.
- Natural organic pigments: are extracted from plants or animals. With few exceptions, these pigments are often no longer used because not adequately bright though they have the advantage of not being toxic.
- Synthetic organic pigments: made from petroleum compounds, they mimic the chemistry of plant and animal colorants.
The parameters defining the characteristics of pigments are:
- Color: can be technically defined in terms of hue, brightness and saturation;
- Intensity of the color: is the capability of a pigment to maintain its hue when mixed with another pigment;
- Resistance to light: capability of a pigment to resist to the effects of light;
- Stability over time: related to resistance to light, it is the pigment’s resistance to atmospheric agents (marine aerosol, industrial emissions, humidity or dryness)
- Solubility: a pigment has to be insoluble in its solvent, a property that is also to be maintained when the pigment has dried;
- Opacity or covering power: the capability to cover the surface it is applied on;
- Chemical stability: the pigment should not to react with other substances such as varnish or additives. Prussian blue or other pigments containing lead are examples of almost inert pigments.
Phase’s line of products includes a wide selection of natural and synthetic pigments that are used in restoration projects thanks to their high compatibility with historic and artistic artefacts. Our products include a broad spectrum of colors and are versatile as they can be used on different supports. Their main characteristics are high robustness, resistance and stability.