Colours of objects in the real world are not pure colours, but objects will reflect and absorb a range of wavelengths.

• Pigments are bits of powder suspended in a medium such as gum, oil or acrylic.
• Dyes are colouring materials dissolved in a liquid solvent.
• Lakes are pigments made from dyes.

Materials to be coloured absorb dyes but pigments lie on the surface.

This is significant in choosing and mixing paints and inks. The brightest colours are produced by mixing warm colours with warm colours, and cool with cool. Mixing warm with cool colours gives more muted and neutral tones as a greater range of wavelengths are reflected.

Development of Pigments

Earth colours: prehistoric

Early humans used earth pigments (coloured clays that are found as soft deposits) on the cave walls such as yellow earth (Ochre), red earth (Ochre) and white chalk. Carbon (Lamp) black was also used, collected from the soot of burning animal fats.

Brighter colours: Egyptians and Chinese

Pigments were produced on a larger scale by the Egyptians and the Chinese. Earth colours were cleaned and washed increasing their strength and purity. Vegetable dyes were also developed by the Egyptians, who discovered the ‘lake’ making process of producing pigment and the basis of this process is still used by Winsor & Newton today to produce Rose Madder Geniune.

Blues and greens: new pigments appeared from minerals such as Malachite and Azurite. Egyptian Blue was first produced around 3,000 BC – a blue glass made from sand and copper which was ground into a powder.

Reds: Cinnabar made from minerals was the first known bright red. In China, the brilliant red that came from Vermilion was developed 2,000 years before it was used by the Romans.

Tyrian Purple came to signify power and wealth and was used by both the Greeks and the Romans. It was complicated to make, cost a fortune and involved using the mucus from thousands of Murex snails.

White: The Greeks also manufactured white lead, the first fully opaque white – namely Flake White and Cremnitz White – which involved stacking lead strips in a confined space amongst vinegar and animal dung.

Renaissance

Burnt Siennas and Umbers: Italians roasted siennas and umbers to make deeper earth colours. Terre Verte (Green Earth) was the principle under-painting colour for flesh tones.Utltramarine: from the semi-precious stone lapis lazuli, found largely in Afghanistan. As the most expensive pigment in the world artists used it to paint The Madonna’s clothing as a way of reflecting her status and power.

Synthetic methods

The opening up of trade routes in the 18th century coupled with advances in technology and science allowed for greater experimentation.

Prussian Blue: In 1704, a German colour maker Diesbach created Prussian Blue by accident in his laboratory and this became the first chemically synthesized colour.

French Ultramarine: 1828 a low cost blue was created by Jean-Baptiste Guimet. The artificial pigment is chemically identical to genuine ultramarine but physically finer and has none of the impurities of the lapis rock.

Chromes: The isolation of new elements in the late 18th century also played a part in providing new colours. Deposits of chrome in the USA in 1820 eased the manufacture of Chrome Yellow, a highly opaque low cost colour available in a variety of hues.

Zinc: The isolation of Zinc gave rise to Zinc Oxide which was used as an artists’ white in preference to lead white as it was less hazardous and more permanent particularly in water colour. However it lacked opacity until 1834 when Winsor & Newton developed a method of heating the oxide to increase its opacity. This new type of Zinc Oxide was called Chinese White.

Alizarin is arguably the most important organic pigment of the 19th century. It was found as a colourant in the roots of the madder plant, but independent work in both Germany and Great Britain managed to duplicate it synthetically in the laboratory – the first time this had ever been achieved. This more affordable synthetic pigment provided a blue shade crimson of strong tinting strength and high transparency and was an immediate hit with artists.

Reduction in price:

The explosion of new pigments during the 19th century, the invention of the metal tube and the arrival of the railways all combined to accelerate this movement. Bright new colours in portable, stable tubes and a method of easy travelling around the country helped give rise to some of the world’s most beautiful paintings.

Sources:
See website: http://www.webexhibits.org/pigments/

Wikipedia: https://en.wikipedia.org/wiki/Pigment