Gamboge

What color is gamboge?

The story of gamboge

Gamboge is the one yellow on the paint rack that doubled as a laxative.

The word is Cambodia, worn down. Camboja was an old name for the country, and the resin came from there and from Thailand, tapped from evergreen trees of the genus Garcinia, mostly Garcinia hanburyi, a tree of about fifteen meters with smooth gray bark. A tree has to be ten years old before it is tapped. Collectors scored the bark and hung hollow bamboo canes to catch the milky yellow latex that bled out; it set hard inside the bamboo, the cane was broken away, and what remained were rods of raw gamboge the shape of the pipe, which is why old color merchants sold pipe gamboge. Joseph Dalton Hooker of Kew gave the tree its Latin name in 1875, eight years before he asked what Indian yellow was made of.

Asia used it long before Europe did. The earliest known use is in Japanese art of the 8th century; it went into paintings, book printing, cloth and by tradition the robes of Buddhist monks, and it did duty as fake gold: the museum found it mixed with silver paint on the south Indian page above. Europe got it by ship from around 1615, when the East India Company began importing it, and valued it first as a purgative and only from the 1650s as a watercolor. In Britain it became a standard transparent yellow, the one in Turner's paintbox, and its classic partner was Prussian blue: the two make the leaf green that William Hooker mixed for his Horticultural Society plates, which is why a tube called Hooker's green exists.

Two problems. The first is light. Gamboge is highly sensitive to it, and Tate's conservators note that gamboge, Indian yellow and the yellow lakes faded even faster than indigo in the washes of Turner's day, which is why so many old landscape washes now read blue where they were once green. The second problem is your stomach. Gamboge is a laxative in small doses and has killed people in large ones; its active compound, gambogic acid, is toxic. It is not a pigment to lick off a brush.

Supply had its own drama. Trade restrictions on the Khmer Rouge in the 1970s and 1980s cut it off, and shipments that did arrive were found to contain bullet casings. What is sold today as new gamboge or gamboge hue is a mixture of modern pigments that copies the color, most often a nickel azo yellow, PY150, sometimes an arylide yellow such as PY97, sometimes with a touch of orange. They are transparent like the resin, lightfast where the resin was not, and they will not purge anyone. The genuine article, Natural Yellow 24 in the Colour Index, has all but vanished from paint racks.

My view is that gamboge is the best argument for reading the back of the tube. The tree and the history are real; the paint that borrows the name today is better on paper in every way that matters, and I would not swap back.

Pigment facts

These describe the pigment in general. Every brand's tube behaves a little differently, so test yours on scrap paper.

How to mix gamboge

Faking gamboge is easy, because it is a plain warm yellow: a golden yellow with a hint of orange, thinned until it glows, is most of the way there. What the resin had that mixtures lack is dye-like transparency, and a modern PY150 tube gives you that back.

Prussian blue is the pairing. One part Prussian blue to two or three parts gamboge gives the deep leaf green of the old botanical plates, the original Hooker's green, which I cover on the olive green page. Push the blue for the shadow side of a hedge; push the yellow and you are in sap green country.

Using gamboge in watercolor

Use gamboge where a leaf has light behind it, where a field goes gold in August, where a wall catches evening sun. It is a yellow for glazing and for greens, and a poor choice for anything that has to cover.

Wet-on-wet, drop it into a still-damp blue and watch the green make itself along the edge; that is the fastest foliage I know. On dry paper, a thin gamboge glaze over a finished gray sky turns a dull afternoon into a warm one without moving a single edge.

It pairs with every blue you own, and with burnt sienna for autumn. Next to cadmium yellow it looks thin, which is the point of it.

One thing I learned the hard way, with a genuine pan I was given: keep it away from your mouth and away from the window. I pointed brushes with my lips for years before I read the label, and a small gamboge-and-Prussian-blue study I hung in a sunny hall turned blue over two summers.

Gamboge vs new gamboge (and Indian yellow)

New gamboge is a modern mixture wearing an old name. Genuine gamboge is the resin: transparent, warm, fugitive and poisonous. New gamboge copies the color with lightfast synthetic pigments, most often nickel azo yellow, PY150. On paper the two look alike for about a year; after that only one of them still does.

Indian yellow is the other historic transparent yellow, and it sits a step toward orange. Gamboge is the yellower of the two and the better one for greens; Indian yellow is warmer and the better one for sunsets. Both faded, and both are hues now.

If new gamboge is gamboge with the problems taken out, Indian yellow is gamboge that has sat a little longer in the evening sun.

More color stories

Mel, founder of Tobio'sI make portable watercolor kits and I named the company after my cat. I write these pages for the beginner I used to be, one pigment at a time.