Traditional yellow pigments in Japan – Part One

Anyone who wasn’t too blitzed at the time will remember the scene where our simian ancestors encounter the large black monolith in Stanley Kubrick’s “2001: A Space Odyssey” (2001年宇宙の旅). The are startled, frightened, frenzied until one intrepid ape edges forward and touches it. From there on learning was a snap and could be passed on genetically. First there were tools and then weapons and all the rest is history. Eventually Johann Strauss wrote the Blue Danube and man went into space. It is so clear: apes, monolith, space. What could be simpler? However, if it had been up to me I would still be flailing my arms and legs about, screeching and snarling and nothing would have gotten me to touch that thing. We would still be living in a state of nature. There would be no tools, no weapons, no wheels, no space adventures, no condoms, no imaginary purple dinosaurs and heaven forbid no television, computers or web logs. But that is not my point. My point is that man’s ability to discover and create absolutely amazes me. I mean, how in the world did our collective ancestors come up with so many fabric and paper dyes, for example and  more specifically yellow dyes? I’ll tell you: Early on they did it all empirically. Accidental discoveries followed by incredibly tedious trial and error methods – for which I have no patience when it is me that has to do it. (Thank goodness they didn’t have televisions to distract them back then.)

According to some scientific articles there were a huge number of yellow dyes used in China, Japan and Korea. Only a few of these have been studied in depth and I will try to limit myself to those used in Japanese woodblock prints. And in the case of ancient Japanese dyes they may not have been empirical discoveries, but rather may have been handed off to them through their contacts with the T’ang Chinese. To complicate matters many of these dyes were so light and air sensitive that I can’t even show you what they looked like when fresh short of collecting the ingredients myself and toiling away until I have produced a weak facsimile – and that is never going to happen. However, I do know enough to show you some of science and the history behind them.

Zumi (酸実  ずみ): A mustard yellow-colored dye extracted from the bark of the Malus sieboldi (also known as the Malus toringo and/or Pyrus toringo) or Japanese flowering crabapple tree. The English common name for this dye is either Cherry Apple or Toringo Crab. Generally ash water was used as a mordant or sometimes iron. If neither was used the dye would be pale yellow as opposed to a dark brown. It has been used in Japan to color fabrics, especially silk, since the 8th century A.D.

The first image shown below was posted by Kenpei at Wikimedia Commons. The second one of the flowering tree was posted at the same site by Wouter Hagen.

Rebecca Salter in her Japanese Woodblock Printing says that zumi was a mustard yellow/green made from boiling the bark and that it deepened as time passed.

The word Malus of Malus Sieboldi comes from the Latin word melum (or malum) for apple. This is related to the Greek melon (malon) which also stands for apple. This in turn is related to the Akkadian word malum for fullness and the Hebrew male for full or abundant.

Flavonoids: The Compact Oxford English Dictionary says that flavonoids are from a “class of compounds including several white or yellow plant pigments.” It also tells us that it is from the Latin flavus for yellow. Now, I am no scientist as you can probably tell, but since it is there – science that is – I do like to look into it. And fortunately I have found a reference to Malus (crabapple) species and flavonoids in a 1982 article by A. H. Williams in the Botanical Journal of the Linnean Society. That’s good enough for me: Crabapple bark, flavonoids, yellow dye. Sweet. Curcumin (C₁₄H₁₄O₄), a constituent in turmeric which gives us the ukon yellow mentioned in the previous post, is a flavonoid. (We dedicated an entire post to ‘ukon’ on June 11, 2009.) Even sweeter.

Lutein (C₄₀H₅₆O₂) is another yellowing-agent flavonoid and luteus is another Latin word for yellow. It turns out that there are quite a few terms for yellow – and shades thereof – in Latin including croceus from which we obviously get the word crocus. In fact there are over 6,000 naturally occuring flavonoids which have been identified so far, but I’ll stick to lutein for now. There is an article from the Journal of Archeological Science from 2007 which identifies lutein found in two yellow dyes used in Chinese textiles from ca. 1000 B.C. How did they know it was lutein? Because they employed “…high performance liquid chromatography with spectrophotometric and mass spectrometric detection.” Get that? Monkey, monolith, mass spectrometric detection. However, they were not able to determine which plants were the sources for these dyes. The paper went on to state  that “Most yellow plant dyes are glycosides (conjugates of sugars with a flavonoid…) and absolutely depend on mass measurement for characterization.” They were able to tell that it was a ‘lutein-type’ flavonoid as opposed to any other flavonoid like the ‘quercetin-type’ because it absorbs the maximum amount of light in a particular range. The authors also tell us that “Many yellow-flowering plants contain luteolin [C₁₅H₁₀O₆] derivatives…” Lutein, a related compound, on the other hand, is C₄₀H₅₆O₂ and can be found in the petals of marigolds and other flowers. At the end of their section on these yellow pigments they mentioned that they had also looked at “…about 200 flavonoid-containing plant dyestuffs…” [Merriam-Webster defines quercetin as “a yellow crystalline pigment C₁₅H₁₀O₇ occurring usually in the form of glycosides in various plants.”]

Another thing to keep in mind is that yellow extracts would rarely have been used purely all by themselves. They would most often have been adulterated by other pigments to create new colors: Yellow + blue = green. That kind of thing. Think of the artist with his palette in hand. A little more chromium yellow, a smidge of burnt sienna, a touch of cadmium red. The greater the mixture the greater the range.

In the Pigment Compendium Dictionary of 2004 it states: “Some flavonoids, such as the anthocyanins, are intensely coloured, giving the red to blue colour in flowers, fruit and leaves; others, like the flavones [C₁₅H₁₀O₂] are essentially colourless. Flavonoids are pervasive throughout the plant kingdom and are present as the principal colourants in many dyestuffs found in nature.” The important point being made here is that flavonoids are not restricted to simply producing yellows.

From the Handbook of Natural Colorants (2009): “The flavonoid family comprises the most widely distributed group of secondary plant products consumed by humans, and are responsible or contribute to the color of many foods. Many fruits and vegetables owe their attractive colors to the presence of flavonoid pigments…” Later they tell us that flavonoid pigments have replaced many synthetic dyes in foodstuffs in recent years. It is certainly healthier for us.

A curiosity: Yellow dyes made from flavonoids are extremely light sensitive yet flavonoids within plants may protect leaves from ultraviolet light damage. They may even leave ultraviolet markings on petals which attract insect pollinators.

In an article from February 2017, ‘Plant Dye Identification in Japanese Woodblock Prints’, the authors noted that originally flavonoids and gamboge were the most common source for yellow colors from 1710 to the 1740s, but that after about one hundred years these were being replaced by “…the predominant use of turmeric and orpiment (an arsenic sulfide mineral) for the elaborate designs and techniques used for full color printing from 1781–1801.”

Tōō (藤黄 とうおう): Gamboge  Not all plants of the genus Garcinia produce the sap which can be turned into gamboge, but some of them do. These include the Garcinia xanthochymus and the G. livingstonei. Other sap producers are G. hanburyi, G. morella, G. cambogia, G. elliptica and G. heterandra. As far as I can tell this genus is not at all native to Japan nor was it imported for production of this pigment, but the raw material must have been. Garcinia seems to be exclusively a tropical plant. Perhaps it could have been grown on Okinawa during the Edo period, but I am not even sure of that. So barring new information I can only assume that gamboge was imported into Japan where it was processed from chunks of hardened resin into a yellow pigment or maybe it arrived that way via an additional middleman.  Perhpas someone could tell me.

“The resin was tapped from the trees from cuts spiraling down the trunks and collected into bamboo canes. The resulting tubes of the solidified pigment (the form in which it was sold) were called pipe gamboge. In its natural hardened state, the resin is a brownish red colour, becoming bright yellow when ground.” From: Pigment Compendium: A Dictionary of Historical Pigments, 2004. While Garcinia contain flavonoids they aren’t the source of the yellow, but rather xanthones (C₁₃H₈O₂) are. It is “…the parent of several natural yellow pigments.” However, “Many of the constituents of gamboge are cytotoxins and the pigment is poisonous…” (Ibid.) “Identifications of gamboge in art are scarce and often imprecise, despite the fact that the pigment was well known and apparently frequently used in both the east and west. Occurences in Japanese art [range] fromt the eighth through the nineteenth centuries…” (Ibid.)

One can’t help but think of all of the other industrial poisons which affected people who worked with materials which at the time were considered necessary to finish their products. There are numerous examples and even today we hear about the human tragedies involved in the mining of asbestos or its removal of it later from our schools, high-rise buildings, etc. Unwittingly we placed these dangerous products there and now we have to take them out. Hatters had mercury, glass workers had lead, modern arists have had to deal with the cadmium issue – an element which when added to the artist’s palette gave them previously unknown and unimagined brilliance and intensity – and the list seems endless. How well did artists and artisans know their products centuries ago? Did they too learn these deadly lessons empirically, too? If a craftsman died a horrible death would their fellow tradesmen know that it was gamboge that caused it? Or, was it just another mysterious death among thousands? Did it take modern chemistry  to alert us to the hazards of gamboge? Not only do we know that it was poisonous, but it would seem that it was a wicked laxative. Surely someone must have learned this lesson the hard way.  Besides, how lethal was gamboge? How dangerous was it just in the handling and application? If I find some of the answers I will let you know. If you know tell me.

The name gamboge has had many diverse variants, but as it is known today it is based on name Cambodia. At times it has been called ‘rattan yellow” and even ‘wisteria yellow’ because the first kanji character, 藤, means wisteria. In China it means rattan. “Shio [another traditional yellow] was used to describe gamboge but was also applied to orpiment and seems to denote simply the colour rather than a specific pigment…” (Pigment Compendium) Shiō (雌黄 しおう) is translated as gamboge in Kenkyusha’s New Japanese-English Dictionary. Jim Breen’s web site gives 雌黄 as 1) orpiment, 2) gamboge and 3) as falsification or alteration.

In the study on the effects of smog on traditional Japanese colorants carried out at Cal Tech they state that the main constituent of shiō is gambogic acid and the source is gamboge resin.

Below are photos of both of these. The first – which I doctored by filling in the background with black – was supplied by Shu Suehiro whose wonderful site can be found at http://www.botanic.jp/ and the second was posted at Wikimedia Commons and had been placed in the public domain by Christopher Hind.

Robert Louis Stevenson wrote: “…gamboge, a hated name although an exquisite pigment, supplied a green of such savoury greeness that today my heart regrets it.”

Clearly Stevenson was on the mark when he referred to gamboge as a hated name. In “The Duke” by Gilbert and Sullivan Rudolph sings:

When you find you’re a broken-down critter,
Who is all of a trimmle and twitter,
With your palate unpleasantly bitter,
As if you’d just bitten a pill –
When your legs are as thin as dividers,
And you’re plagued with unruly insiders,
And your spine is all creepy with spiders,
And you’re highly gamboge in the gill –
Creepy! Creepy!

G. K. Chesterton in The Man Who Knew Too Much had this colorful passage: “Why talk about his blue blood? His blood may be gamboge yellow with green spots, for all anybody knows.”

In Blackmore’s Lorna Doone there is a description of stranded sheep in a winter snowstorm “…the churned snow beneath their feet was as yellow as gamboge.”

I am not a colorist and as anyone knows there are an enormous number of shades which range within a particular color. Think ‘blue’. Possibly no two readers of this post will think of exactly the same blues. Some will be close, but not the same. Another factor is the computer screen and its settings. What I post and see on my monitor is not what you will see on yours. On any number of times I have used computers owned by friends and while looking at familiar web sites they look almost completely unidentifiable. At best their monitor will approximate mine. That said, here below is what I believe is (one shade) of  tōō. Don’t put money on it.

There is a passage in The Organic Chemistry of Museum Objects (1999) which deals with the creation of various greens through the use of blues + yellows: “Some colours, most importantly green, are often obtained using combinations of others for lack of a good single dye. Green is formed by dyeing twice, first with indigo… and then with one of the yellow flavonoid dyes. A comparable way of producing the colour is used in Japanese prints (gamboge over indigo or, later Prussian blue), and sometimes in European – especially Dutch seventeenth century – oil paintings yellow lake over a blue underpaint). All three of these green colorations in time tend to suffer from the same defect: the more light-fugitive yellows fade leaving only the blue.”

Enju (槐 えんじゅ): The Sophora japonica or Styphnolobium japonicum, known as the Japanese pagoda tree and/or the Chinese scholar tree. The monk Sōchō once wrote about taking mulberry baths “…with the five trees and eight herbs…” all used for medicinal purposes. While there seem to be some differences about which trees were the five mentioned one of them is believed to have been the pagoda tree. In Mansfeld’s Encyclopedia of Agriculture and Horticultural Crops it is also called an umbrella tree and states clearly that a yellow dye was extracted from the flower buds mainly for use on silk fabrics. The buds and pods were used for medicinal purposes. In The Guide to Trees published by Simon and Schuster it says that this tree can grow up to 65′ tall and “…as it grows old, [its trunk] often becomes curiously twisted and knotted…” Of course, this is not always true, but the image shown below of one example from an Italian garden at the Villa Medici at Poggio a Caiano is a glorious example. It was posted at commons.wikimedia.org by Warburg.

In Italy this tree is referred to as Robinia del Giappone. The Robinia part is named “After the French botanist Jean Robin 1550-1629, royal gardener and herbalist to Henri IV of France, from 1590 at the Jardin des Plantes, Paris…” Sophora has an Arabic origin in their words sophera or sufayra. Linnaeus was the first to use sophora.

Sophora japonica flower buds
Sample provided by the MFA Asian Conservation Studio.
Image provided by CAMEO

Next is a photo of the pods by Tracy originally posted at Flickr, but found at commons.wikimedia, too. The photo of the flowers is from Shu Suehiro’s botanical site.

In a 1993 there was a publication which gave a rather dismal report about the effect of nitrogen dioxide on enju dyed materials. Exposed in a kind of gas chamber devoid of light enju did the worst out of 23 different “…natural dyes traditionally used in Japan on silk and found that, in most cases, the changes were small. The largest color change occurred in Enju… Whitmore and Cass [1989] rated the change as noticeable.”

Professor Idema, who teaches Chinese literature at Harvard, published a book in 2009 entitled Filial Piety and Its Divine Rewards: The Legend of Dong Yong and Weaving Maiden, With Related Texts. Centered around just one of the 24 stories of filial piety he focuses in on Dong Yong (董永). The reason I have added it to this post is because of just one sentence. Dong Yong is incredibly poor and when his father dies he doesn’t have the financial means to bury him. So he sells himself into servitude in exchange for a loan to cover the expenses. After the burial our hero is walking along a road back to his new master when he meets a woman whom he marries. She joins him in his servitude: “…and together they arrived at the master’s house. The master ordered her to weave three hundred bolts of double-threaded silk…” and then they would be freed. It only takes her one month to complete her task – an unearthly feat. “…on the way back home they arrived at the spot where they had met in the shade of a scholar tree, she said goodbye to Yong and disappeared.” It turns out she was the heavenly Weaver Maiden.

Professor Idema added this passage:

To bury his father he needed to borrow money;
Out on the road he ran into an immortal beauty.
Weaving silk she paid off his debt to his master:
His filial piety managed to move the sky above!

Below are details from two versions of the story of Dong Yong by Kuniyoshi. One shows no trees – except maybe in the far distance – and in the other there are trees present but they don’t play a primary role. Perhaps Kuniyoshi was working from different versions. There are tons of them.

The Sophora japonica was said to have been introduced into England in 1753 and America by 1811. It was in the Jardin du Roi in France by 1747.

This tree has few pests and blooms in August long after most other trees.

An 1885 publication said that in China an extract of the leaves was used to adulterate opium and that the wood of this tree was used to start fires. In an 1888 [British] Journal of the Society of Arts it states: “The Sophora japonica is cultivated in all of the eastern provinces of China for the sake of the imperial yellow dye obtained from its bunches of flowers and undeveloped flower buds. They are gathered, separated from the calyx and dried in the sun.” Father Cibot of the Society of Jesus traveled to China in the 1770s and described an alternative drying process for the flower buds: “…or, still better, in an iron pan, when they are turned as if they were to be roasted. They are then moistened with the juice of other flowers, piled in a heap, and strewed with salt. When thoroughly manipulated, they are formed into balls, and set to dry in a northern aspect. Some people, instead of salt, use lime, or content themselves with sprinkling it over the flowers, after reducing it to a fine powder.”

In volume 1 of the Technologist of 1861 there is a description of the process from a Cantonese dyer. “Take boiling water, put in the hoai-hoa [i.e., Sophora japonica buds], and leave it for some time. After a while the colour and the odour are both developed. Pour off; the sediment is of no use. Take this water; add cold water to reduce its temperature; add lime water, and dip the cloth in the bath thus prepared. Let the cloth be well shaken, and then rinsed in pure water. After being rinsed, the cloth will be found dyed a fair yellow. A little alum is required to complete the process. Put the cloth, first of all, in some alum water, for twenty-four hours; then dip and the process is complete.”

The main constituent which gives the yellow color is rutin. European experiments dying different fabrics using different mordants gave varied results: Cotton would yield a pure yellow, but on wool using a chromium mordant the color would come out a dull orange; with alumina a moderately brilliant yellow; bright yellow with tin; and a dark olive with iron. Supposedly it was introduced as a dye stuff in Europe in 1846.

According to the Museum of Fine Arts in Boston, rutin has several sources: “A yellow colorant found in flower buds of the Japanese pagoda tree (Sophora japonica), forsythia flowers (Forsythia suspensa), tobacco leaves (Nicotiana tobacum), and buckwheat kernels (Fagopyrum esculentum). Rutin precipitates as pale yellow crystals from a hot water extract. The color darkens to brown with exposure to light or heat.”

There is a footnote to a modern edition of a Chinese book published in 1637 that talks about the Sophora japonica or huai “…considered the fittest tree for the imperial palace as well as meeting places of highest officials. The cultivation of huai trees and the use of their flower-buds as a yellow dyestuff are respectively mentioned in Ch’i-min yao-shu (fifth century) and Pen-ts’ao shih-i (eighth century). The method of dyeing, not described in the present book, consists in simply boiling mordant-treated silk for one to one and one-half hours in decoction of the flower buds. When applied to wool, the huai buds give a dull orange color with chromium as a mordant, a yellow of moderate brilliancy with aluminum, a bright yellow with tin, and a dark olive with iron.” It was already referenced during the Chou dynasty long before the time of Christ.

On July 1, 2011 I ran across this technical information: “In the same study, the yellow colorant enju was also observed to be very light sensitive. The degree of sensitivity appears to depend on which part of the plant is used as the source of the dye, which can be as fugitive as aigami. Interestingly, enju has been identified as a glycoside of quercetin (that is, like aigami, it is also a flavonoid glycoside), which raises the possibility that the color and light sensitivity of enju also depends on its state of aggregation.”  In a comment following this passage the author states that ten uses of a photoflash on prints with enju or aigami has the same effect as a lifetime of light exposure.  These come from Effects of Light on Materials in Collections: Data on Photoflash and Related Sources: Research in Conservation by Terry Schaeffer .

For more information about Japanese prints and culture please visit our other web site at http://www.printsofjapn.com/.