Watercolour and gouache: These colours that dance between light and memory
Imagine a morning in 1835, somewhere along the banks of the Thames. A man in a frock coat, his hair tousled by the wind, unfolds a portable easel and pulls small pans of vibrant hues from his satchel. He dips his brush into the river’s murky water and, with a swift stroke, lays down a streak of ultramarine that unfurls like morning mist. This is no ordinary painter—it is J.M.W. Turner, and before our eyes, he has just invented a new way of capturing light. On that day, watercolour was no longer a mere study tool but a medium in its own right, capable of rivalling oil through its ethereal transparency. A few decades later, in Parisian studios, garish posters with opaque colours began to plaster the walls—gouache, that rebellious cousin of watercolour, had become the secret weapon of modern artists.
By Artedusa
••10 min readYet these two mediums share a fragility that makes them as precious as they are capricious. Once applied, their pigments become living things, sensitive to moisture, light, and the passage of time. A watercolour by Turner, displayed too long, fades like a memory slipping away; a gouache by Matisse, poorly preserved, cracks like parched skin. So how does one choose between these two feuding sisters? How to tame them, protect them, make them last? And above all, how to understand their soul—that unique alchemy where water, pigment, and paper unite to create works that seem to breathe?
01When water becomes brush: the ephemeral miracle of watercolour
There is something almost magical in the way watercolour behaves on paper. Place a drop of water tinted with carmine red on a still-damp sheet, and you will see the colour spread in soft, blurred halos, like a wine stain on linen. This is what the English call the bloom—that moment when the pigment, freed from all constraint, dances across the paper’s surface before fixing itself for eternity… or nearly so.
The masters of this medium have always played with this instability. Take Albrecht Dürer’s botanical studies: his Irises and Tuft of Grass (1503) seem alive, their petals translucent as if freshly plucked. Dürer used a then-revolutionary technique, layering washes so diluted that each had to dry before the next was added. The result? Shadows that seem to breathe, light that passes through the paper as if through glass. But this transparency comes at a cost: expose these works to direct light, and their colours evaporate within decades. The cobalt blues, so intense under Turner’s brush, turn greyish; the emerald greens of Constable’s landscapes yellow like autumn leaves.
Yet it is precisely this fragility that gives watercolour its unique charm. Unlike oil, which freezes time in thick layers of matter, watercolour captures the moment with an almost immaterial lightness. Constable’s Cloud Studies, painted outdoors on loose sheets, are less paintings than fragments of sky snatched from the ephemeral. And perhaps this is why contemporary artists like David Hockney continue to embrace it: in his iPad watercolours, the digital strokes mimic the fluidity of the traditional medium, as if watercolour, even dematerialised, retains its power of suggestion.
02Gouache, or the art of mastering opacity
If watercolour is a dance with impermanence, gouache is a declaration of war on transparency. Imagine a tube of paint that, once squeezed, reveals a thick, velvety paste capable of covering paper in a single stroke—like spreading cream on a cake. It is this opacity that seduced twentieth-century artists, from Lissitzky’s revolutionary posters to Matisse’s vibrant cut-outs.
Gouache has a far older history than one might think. Medieval illuminators already used it to give manuscripts colours so vivid they still appear fresh today. Look closely at the Book of Kells (ninth century): the vermilion reds and lapis lazuli blues, applied in thick layers, have withstood the centuries thanks to their density. But it was in the nineteenth century that gouache reached its golden age, with Toulouse-Lautrec’s posters. His Aristide Bruant (1892) or La Goulue (1891) owe their visual impact to the technique: the flat, saturated colours leap out like shouts in the Parisian night.
Yet gouache is not merely a medium of the moment. In his later years, Matisse turned it into a tool of liberation. Bedridden by illness, he cut shapes from gouache-painted paper, creating compositions like The Sorrow of the King (1952), where colours seem to float in space. These works, now displayed at the Centre Pompidou, raise a fascinating question: how can a medium so fragile give birth to images of such power? The answer may lie in its very texture—that paste which, once dry, cracks like parched earth, a reminder that even opacity has its limits.
03Paper, the silent accomplice
Choosing the right paper for watercolour or gouache is a bit like choosing a dance partner: the slightest incompatibility comes at a cost. Eighteenth-century artists understood this well. Turner, for instance, used Whatman paper, made from linen and cotton rags, its slightly textured surface allowing pigments to cling without bleeding. Today, watercolourists can choose between three main types of paper, each offering a radically different experience:
- Hot-pressed, smooth as a baby’s skin, ideal for intricate details (Sargent’s portraits are a perfect example).
- Cold-pressed, rougher, giving washes an almost organic texture (observe Cézanne’s landscapes, where each brushstroke seems sculpted into the material).
- Satin-finish, a compromise between the two, often used in modern illustration.
But the real challenge is thickness. Paper that is too thin warps under water, like a dead leaf in the rain. Professional artists usually opt for 300 gsm—thick enough to withstand successive layers, yet supple enough for layering effects. Then there is the question of colour: paper that is too white can make watercolours look artificial, while an ivory or chamois tone lends a natural warmth, as in John Constable’s landscape studies.
For gouache, the choice is even more critical. Paper that is too absorbent swallows the paint, dulling its brilliance; a surface that is too smooth prevents pigments from adhering properly. Illustrators like Mary Blair, who worked for Disney in the 1950s, preferred thick, slightly textured papers that could withstand multiple layers without warping. Her designs for Cinderella (1950), with their saturated colours and geometric shapes, are a perfect example of this alchemy between support and medium.
04The invisible enemies: light, humidity, and time
A well-preserved watercolour or gouache can last for centuries; poorly protected, it fades within decades. The first enemy is light. Ultraviolet rays, in particular, attack organic pigments like carmine or Indian yellow, turning them brownish. Museums understand this well: works on paper are rarely displayed permanently, and when they are, it is under dim, UV-filtered lighting. Look at Turner’s watercolours at Tate Britain: they are shown in rooms with grey-blue walls, under soft lighting that preserves their delicate hues.
Humidity is just as dangerous. A room that is too damp warps the paper, while air that is too dry makes it brittle. Art restorers know this dilemma well: to preserve Matisse’s gouaches, museum storage rooms are kept at a constant 20°C, with 50% humidity. And what of insects? Moths and mould love paper, especially if it is glued to an acidic backing. In the 1980s, conservators made a horrifying discovery: works by Paul Klee, stored in inadequate conditions, were being eaten away by microscopic fungi. Since then, museums have used conservation boxes made from neutral materials like museum board to isolate artworks from their environment.
But perhaps the worst enemy is ignorance. How many watercolours have been lost because a collector framed them with ordinary glass or hung them above a fireplace? How many gouaches have cracked because an artist used the wrong fixative? Preserving these mediums is almost an art in itself—one that demands patience, skill, and a certain humility in the face of their fragility.
05The art of repair: when artworks rebel
Sometimes, despite all precautions, a watercolour or gouache deteriorates. The paper yellows, the colours fade, the edges tear. What then? Art restorers have developed techniques as precise as they are delicate to breathe new life into these capricious works.
Take Constable’s Cloud Studies. In the 1990s, several of these works were damaged by prolonged exposure to light. The restorers at the Victoria and Albert Museum turned to a revolutionary method: controlled washing. By carefully immersing the sheets in distilled water, they removed years of accumulated impurities while preserving the original pigments. The result? Skies that regained their former luminosity, as if time itself had been erased.
Restoring gouaches is often more complex. Thick layers of paint can crack over time, especially if the work has been rolled or folded. Restorers use methylcellulose gels, applied with a brush, to rehydrate the paint and make it adhere to the support again. It is a delicate operation, requiring a steady hand: too much water, and the colours bleed; too little, and the cracks remain.
But restoration is not limited to modern techniques. In the nineteenth century, artists had their own tricks. Turner, for example, used honey or gum arabic to revive the colours of his watercolours before exhibiting them. Today, these artisanal methods are sometimes revived, particularly for works too fragile to undergo chemical treatment. After all, restoring a watercolour or gouache is a bit like healing a living thing: one must respect its history, its scars, and accept that some wounds never fully close.
06Choosing sides: watercolour or gouache?
Still undecided between these two mediums? It all depends on what you wish to express. Watercolour, with its transparency and fluidity, is ideal for capturing the ephemeral: a sunset, morning mist, the fleeting glow of a face. It demands patience, a certain humility in the face of its whims, but rewards those who listen to it with unparalleled effects of light.
Gouache, on the other hand, is for those who like to control their art. Its opacity allows for corrections, layering, and bold contrasts without fear of bleeding. It is perfect for illustrations, posters, and set designs—in short, for anything that requires precision and vibrancy. But beware: its thick texture may put off those who prefer watercolour’s lightness.
And if you take away just one thing? Despite their differences, these two mediums share the same essence: they are made to be seen up close, admired in their details, cherished like precious objects. A watercolour by Turner or a gouache by Matisse is not contemplated like an oil painting hung in a living room. They are discovered, like secrets, in the intimacy of a studio or private collection. They demand that you lean in, that you notice the brushstrokes, the accidental drips, those imperfections that make them beautiful.
So the next time you hold a pan of watercolour or a tube of gouache in your hands, remember: you are not just holding paint. You are holding a piece of history, a promise of light, and perhaps—if you know how to listen—the key to an ephemeral masterpiece.