One of our proudest achievements at Winsor & Newton is the way we have maintained our distinctive rose madder shade through the ages. Although the process of producing this signature colour has evolved over time, the quality and authenticity remains unchanged. From this comes rich and tender colour such as Rose Madder Genuine, available as an oil or watercolour in the Winsor & Newton Artists’ Oil Colour and Professional Watercolour ranges. We are proud to still be the sole supplier of this particular bright and subtle rose red shade.
Across the ages
The term rose madder is most commonly used to describe the colour made from the madder lake pigment, which is a traditional lake pigment extracted from the roots of the common madder plant Rubia tinctorum. Madder root pigment was found in the tomb of the pharaoh Tutankhamun and in the ruins of Pompeii and ancient Corinth. In the middle ages, Charlemagne encouraged madder cultivation as it grew well in the sandy soils of the Netherlands and became an important part of the economy. When industrialisation was at its height in Great Britain during the 1860s, imports of Madder were valued at £1.25 million.
George Field at the forefront
One of the most instrumental people in helping make madder and lake colours that didn’t fade over time was George Field (1777-1854). Field was an outstanding colourman and chemist and by 1804 he had turned the madder extract, which was soluble in water, into a solid pigment that was insoluble. This resulted in what was known as a madder lake. It had a longer-lasting colour and could be used in creating paints. Pigments made from madder root varied from rose to brown and were used by contemporary painters of the day, among them John Constable and William Holman Hunt.
Developing the original process
Lake colours were pigments made by bringing together, or “fixing”, a dye with an insoluble substance or “base”, in this case hydrate of aluminium or sulphate of calcium. Field wrote 10 volumes of notes and experiments on how to improve the quality of pigments and these notes were considered so important by William Winsor, the co-founder of Winsor & Newton, that he bought the lot.
To increase the speed, quality and efficiency of pigment production, Field designed a lake “laboratory”, shown in one of his notebooks dating from 1809. This system was used by Winsor & Newton as the basis for our own lake laboratory.
Working with artists in mind
For a pigment to be suitable for artists’ colours, it needs to have certain qualities, including hue, colour strength, brightness, transparency, lightfastness and ease of dispersion. The method of manufacture has a critical effect on most of these.
For the chemists among us, the natural colouring matter of madder is ruberythric acid, a clycoside of a number of anthraquinone dyes and mono saccharides (cellulose or plant based derivatives). The main dyes, or colourants, are alizarin (1,2-dihyroxyanthraquinone) and purpurin (1,2,4-trihyroxyanthraquinone). These dyes were discovered in 1826 by two French chemists, Jean-Jacques Colin and Pierre-Jean Robiquet.
In the original process to produce the pigment for Rose Madder Genuine (Natural Red 9), which is a transparent colour, it was important to separate the cellulosic (plant-based) materials from the dyes. The main methods were acid hydrolysis fermentation (enzyme) and mordant extraction.
Aluminium hydroxide gave the optimum transparency, so the dye was extracted using alum. The lake pigment is what was left after it underwent a chemical reaction with alkali known as precipitation. If metal impurities found their way into the process it could alter the colour, so wooden vats and stirrers were used. But metal salts could be added intentionally to produce other colours such as brown madder and purple madder.
Although based on the three-tier design of George Field, Winsor & Newton only used two levels, using the hydraulic head to pass the precipitate slurry onto the filters instead of gravity. The first filtration of the pigment was through linen filters, using gravity to remove excess water. The pigment was also washed free of soluble salts produced in the precipitation process.
As with most precipitation processes, the purest product was produced by means of a process which remains a Winsor & Newton secret to this day. The pigment was finally filtered using a beam press and then dried.
Real madder and proud of it
The production of rose madder has since been brought up to date and now uses state of the art production facilities to maintain the well-known shade. It usually takes an average of 13 weeks to produce pigments for both oil and watercolours. Many other methods, old and new, have been tried to produce the pigment. But none have been found to match the unique properties of the rose madder produced following Field’s methods, and Winsor & Newton is proud to be part of an age-old tradition.