Understanding the Composition of Water Colour
The brilliance and transparency of water colour make it an exceptional medium. Unlike any other, it is capable of producing an amazing variety of effects from subtle washes to brilliant, translucent colour. Emma Pearce explains the importance of understanding the make-up of water colour in order to get the most out of this astonishing medium..
A little history first
Water colour has existed, in some form, since man first mixed pigment and water to make images. Until the 18th century, however, artists had to grind pigment and gum-based water together every time they wanted to paint. This maintained painting as a profession as one needed knowledge, skill and staff to make the materials of the trade.
In 1766, William Reeves introduced the first water colour ‘cakes'. Having noticed the humectant qualities of honey, William produced a ready-made product which could release colour by rubbing on a palette. This was an instant success, William had a Royal Warrant within the year and the educational accomplishment of painting was added to those of poetry and music. Painting became a leisure past-time for the first time.
 Reeves Water colour Cakes |
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 Winsor & Newton Moist Water Colour |
In 1832, two young friends, William Winsor and Henry Newton invented water colour as we know it today by using glycerine. This produced a ‘moist' water colour which was a pure colour instantly released with a wet brush. This was the beginning of modern water colour.
Water colour composition
The composition of water colour can be generally divided into Binder, Other Ingredients and Pigment.
Binder
The critical ingredient in water colour is Gum Arabic. No synthetic material can produce the handling and flow properties of natural gum. Gum Arabic is harvested from Acacia trees which grow all over Africa. The very best quality is either Kordofan or Senegal gum (from Acacia Senegal) because these are not as resoluble.
 Pigment & Gum Arabic (Kordofan) |
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From the raw material, Winsor & Newton then make up a number of different gum solutions. These vary in strength but also have a selection of secret ingredients. These solutions are still called by the numbers and letters originally used by Winsor and Newton in order to keep their recipes confidential.
Each colour formulation will be made up of any number of these solutions in varying amounts and with over 100 formulations, experience and knowledge are vital to ensure the consistency of the colours. It can take the water colour chemist a number of weeks to define the right balance of binder for a particular pigment and if it isn't right, the colour will be hard and insoluble or soft and too liquid.
Water colour washes need to be lush and strong but they still need to be relatively insoluble when dry on the paper. The ability to superimpose washes, without them becoming muddy or dissolving one another is one of the characteristics of Winsor & Newton Artists' Water Colour that is most appreciated by artists.
Other Ingredients
Ox gall is used as a wetting agent in the colour formulation. This makes the colour ‘wet' the paper and spread across the surface. Once more, the oldest product remains the best as too strong a wetting agent would increase staining of the paper and make controlling the colour more difficult for the artist.
Glycerine is the moisture retaining ingredient which makes water colour possible. Winsor & Newton kept its use a secret for many decades. Professor Church, author and Professor of Chemistry at the Royal Academy wrote in The Chemistry of Paints and Painting at the end of the 19th century, ‘The water-attracting property of glycerine induced me to use it........so long ago as 1856, when I recommended its employment for this purpose to the late Mr. Winsor'. It must have still been a pretty good secret if Church didn't realise that Mr Winsor had been using it since 1832!
Glycerine must be used carefully. If there is not enough the colours will not release into the water, however use too much and the painting will continue to attract moisture, encouraging dampness and mould.
Preservative of some sort is required to prevent the gum and therefore the colour from going mouldy. In the 19th century formaldehyde would have been used but like so many chemicals, this has been superseded by safer biocides.
Pigment
Pigment provides the colour and water colour relies upon the individual characteristics of the pigments more than any other media. The variations of hue, top tone, undertone, brightness, colour strength, saturation, opacity, granulation and staining can all offer unique effects on paper. The maxim ‘you can mix everything from primary colours' could not be further from the truth in water colour.
 Pigment |
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For example, Rose Madder Genuine is a unique hue, a pink which cannot be mixed from red and white. With low colour strength, transparency and granulation it has such delicacy and charm which entices painters to rush to use it. With its roots dating back to the 7
th century BC, Rose Madder Genuine was also used by Turner and William Blake. Today Winsor & Newton remains the only brand to make its own Rose Madder pigment from the roots of the Madder plant.
By comparison is Permanent Rose which is right next to Rose Madder Genuine in the spectrum. A dilute Permanent Rose would be closest to Rose Madder Genuine in hue but there ends the similarity. Permanent Rose is one of the most highly transparent of all pigments, making it ideal for mixing other colours and making optical mixtures in layers. It is very strong, a little goes a long way and it has such fine particles it stains the paper madly.
 Rose Madder Roots |
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 Rose Madder Pigment |
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These stark differences exist with every other comparison of colours in the range, it takes 87 different pigments to make 96 Artists' Water Colour hues. The best possible range of water colours should offer every artist endless possibilities.
NB. A note on permanence
Tate Britain are currently showing a highly successful exhibition on water colour. This is being deemed as the most ambitious exhibition about water colour ever to be staged, with works spanning 800 years, celebrating the full variety of ways water colour has been used. However, in some of the press coverage, comments were made about the appalling permanence of water colours. There can be such confusion about the past and present in painting!
Going back a hundred years and more there were far fewer pigments available and as water colour is such a thin paint film, water colours did fade quicker than oils.
In the 21st century, however, pigments are so very permanent that despite the thin films, water colours are now equal in permanence to any other media.
Explore and enjoy water colour, the world is your oyster!
Visit WATERCOLOUR at Tate Britain, 16 February - 21 August to enjoy one of the largest ever water colour exhibitions, spanning more than 800 years of this medium. See items loaned from the Winsor & Newton Museum within the exhibition.