Carnets de Voyages: A bit more about colour… BLUE

Bois-Barbu, Acrylic on canvas, 215x80cm, March 2009

As you may have noticed I have recently been using a lot of blue in my paintings, so today I will try to give some history about the colour, where it comes from and how it has developed.

Pigments. What are they?

We can find two main sources of colour: pigments and dyes. Painters most commonly use pigments (composed of finely divided particles) that are mixed with a binding medium. In most instances, dyes are not used in paint manufacture but are reserved for the textile industry because dyes are resoluble, without body/solidity and tend to fade when exposed to light.

When we view pigments they appear as they do because they selectively reflect and absorb certain wavelengths of light. For example, Ultramarine reflects blue light and absorbs other colors.

There are two main sources of pigments: inorganic and organic.

Inorganic pigments are derived from compounds that were never part of living matter such as earth deposits, mineral/rocks, treated metallic compounds or fused metallic compounds. Organic pigments, on the other hand, are derived from living substances or substances that were once part of living things like animals, plants or synthetic treatment of plants.

Ultramarine, Phtahlo blue and Prussian blue

Now that we know what pigments are, I will focus on three colours blue (and I don’t mean Kieslowski’s film!). Ultramarine, Phtahlo blue and Prussian blue are the ones that dominate my recent work. I will (very) briefly explain their characteristics and use throughout the history of art.

Ultramarine: Originally, natural ultramarine was derived from the semi-precious stone lapis lazuli. The name ultramarine comes from the Italian Oltramarino, which means ‘from beyond the seas’.

The stone is composed of the blue mineral, lazurite, with the addition of calcspar and iron pyrite. The original source for lapis lazuli was in the valley of the Kokcha river in the province of Badakshan, northeastern Afghanistan. These lapis mines were mentioned by Marco Polo in 1271, who noted that the stones were processed to make colour. “There are mountains likewise in which are found veins of lapis lazuli, the stone which yields the azur colour ultramarine, here the finest in the world. The mines of silver, copper and lead are likewise very productive.”. Lapis Lazuli from Afghanistan was imported into Europe through Venice, the main trading port between Europe and the East at the time.

Lapis lazuli was extensively used throughout the Renaissance, especially in Italy and during the golden period of Venetian painting in the 1600s. Because the best sources of lapis were remote and no other pigments offered the same deep transparent blue, blue remained an exclusive color, associated with wealth and status. It is this costly pigment that is often used to depict the Virgin Mary’s garment.

The 17th century Dutch master Johannes Vermeer frequently made lavish use of lapis lazuli in paintings such as ‘The Milkmaid’ or ‘Woman in Blue Reading a Letter’.

Artists at that time could have used a cheaper mineral called azurite. Azurite was sometimes called ‘citramarino’ indicating that it came from this side of the seas (from Germany, for example). Azurite is a by-product of the copper mines and is a sister stone to malachite. Thus it naturally tends towards the green side of the spectrum, whereas ultramarine leans towards violet. The cheaper pigment is also far less stable and had a tendency to fade.

French Ultramarine Blue: In the 1830’s France and Germany started to produce an artificial mineral pigment that replaced the costly natural ultramarine, lapis lazuli. In 1824, the Société d’Encouragement pour l’Industrie Nationale offered 6,000 francs to anyone who could make a paint all artists could afford – just 300 francs a kilo and less than a tenth of the cost of the real ultramarine. Two chemists claimed the prize – Jean-Baptiste Guimet of France and Christian Gmelin in Germany. They battled over the blues for several years but eventually Guimet got the prize and his discovery has been called ‘French Ultramarine’ ever since. This modern synthetic pigment is made by heating clay, soda, sulphur and coal. It offers a deep blue with grades from green-blue to red-violet.

The Impressionist Pierre-Auguste Renoir worked using French Ultramarine blue in Les Parapluies (The Umbrellas), which shows a busy Paris street in the rain. Renoir used a lake / cobalt blue mixture for the blue and purple colours that dominate the picture, although he later completed the work using French ultramarine blue, a synthetic variant of natural ultramarine.

Prussian blue: Prussian blue is an artificial inorganic pigment with a bluish-black tone. It was discovered by accident in Berlin when a paint-maker was trying to produce red. One day in 1704, Herr Diesbach was settling down to make carmine lake according to a tried and tested recipe – mixing ground-up cochineal, alum and ferrous sulphate, then precipitating it all with an alkali – when he realized he had run out of alkali. He borrowed some from his boss, but did not realize it has been distilled with animal oil. To his amazement he found blue instead of red in his flask. The clue was in the animal element: the mixture had contained blood, which itself contains an element of iron. Diesbach had unwittingly created iron ferrocyanide, which was dubbed ‘Prussian Blue’. It became instantly popular and introduced as an artist’s pigment. Its name comes from the fact that it was first extensively used to dye the dark blue uniforms of the Prussian army.

This Prussian blue pigment is significant since it was the first stable and lightfast blue pigment to be widely used. European painters had previously used a number of pigments such as indigo dye, smalt, and Tyrian purple, which tended to fade, or the extremely expensive ultramarine from lapis lazuli. Similarly, Japanese painters and woodblock print artists did not have access to a long-lasting blue pigment until they began to import Prussian blue from Europe. Hokusai for instance used Prussian blue to produce his famous piece ‘The Great Wave’. Cobalt blue has been used extensively by Chinese artists in blue and white porcelains for centuries, and was introduced to Europe in the 18th century.

Note: Prussian Blue is never used in the preparation of acrylic colours, as it reacts with the alkaline nature of acrylic resin binders. In acrylic paint ranges, a replacement for Prussian blue can be prepared by mixing phthalocyanine blue with a small addition of lamp/carbon black.

Phthalo blue: Phthalo blue is a synthetic organic pigment, which was invented in1928 and introduced to the market in the 1930s. It is a very bright and transparent blue that contains copper. I used Phthalo blue in the painting below.