Ukon 鬱金 turmeric

This is a post about something which isn’t there – or, at least, we can’t see it. It might be detectable with the most sophisticated machinery, but it certainly isn’t visible. There were three extremely fugitive vegetable dyes used to color Japanese woodblock prints in the 18th century: Aigami (藍紙 or あいがみ), a beautiful blue extracted from the day flower; benibana ( 紅花 or べにばな), a rich red from safflower; and ukon (鬱金 or うこん), a deep yellow produced from the root of the turmeric (C₂₁H₂₀O₆). The use of these colors ‘hot off the presses’ must have helped spread the popularity of artists like Harunobu (1724-70). Gorgeous, lithe, androgynous-like figures dressed in deep yellows and reds standing along gently flowing rivers which naturally would have been a strong (but also delicate) blue. The effects were brilliant and perhaps just a bit startlingly fresh. In the 1760s the colors were mainly flat and filled their assigned fields – not like the subtleties of ink paintings – especially the gradations of sumi-e – which the upper classes liked so much. These small, multiple prints would have struck them as boorish and garish and not worth their time. But to the rising middle class and some of the samurai, too, they were a breath of fresh air.

What we see today is a faint hint of what these prints once looked like. However, even the Mona Lisa looked a hell of a lot fresher on Leonardo’s easel than it does today behind bullet proof glass hanging in the Louvre. Many of the areas we see on Harunobu’s prints today are only shadows of their former selves – maybe less than that. The aigami blue, the safflower red and the ukon yellow are often gone completely or at least indistinguishable to the naked eye. One major contemporary conservationist even said that UV glass would not keep those colors from fading. And yet, in some museums and private collections, there are still a number of  Harunobu’s which retain some color. One example is the yellow of the umbrella shown below. Yet here the yellow may be derived from enju (槐 or えんじゅ) acquired from the pagoda tree or Sophora japonica (aka Styphnolobium japonicum) which was somewhat more colorfast than ukon. However there were quite a few other organic sources for traditional yellow dyes – used either for prints or fabrics – including zumi for a mustard yellow, shiō, kariyasu, kihada, yamamomo, kuchinashi, and the inorganic kio which is also called sekiō. The brighter ukon would now just look like the paper it was printed on or maybe those gray bands on the umbrella or some other shade of drab.

And then again it may not even be enju. I don’t know. It would take a lot of expensive, high-tech equipment and scientific analysis to make an absolute, ironclad identification.

Curcumin (C₂₁H₂₀O₆) is the flavonoid compound which gives turmeric its yellow color and is the reason it fades so dramatically. In The Organic Chemistry of Museum Objects it states: “The effects of relative humidity on photo-chemical fading of a number of natural pigments have been reported… The effects of some air pollutants on fading of dyes has also received some study. Unsurprisingly, ozone reacts with (and fades) dyestuffs containing olefinic double bonds such as curcumin, indigo and alizarin. Its effects on the whole range of traditional Japanese pigments including the three just mentioned have been assessed; some such as cochineal lake and gamboge were found to be somewhat less affected.”

“…turmeric, whose colouring matter, curcumin, was first isolated by Vogel in 1842. Though obtained crystalline by Daube in 1870 it was not until 1897 that Giacomo Ciamician (1857-1922) and Paul Silber (1851-1932) ascertained that its molecular weight is represented by C₂₁H₂₀O₆ rather than by the older expression C₁₄H₁₄O₄. ” This is from information provided by Arthur George Perkin in 1918. Of course, this would make the information previously posted incorrect. Someone has to be wrong. Someone has to be misinformed. Wait! That’s me. Sorry. That’s what’s wrong with blogs, in general. They are founts filled with egregious mistakes and erroneous opinions, but, then again, this is the Internet.  Again, I apologize. The mistake has been corrected. Now back to business. But first… I found what I think was my ‘expert’ source for this error. Webster’s 1913 dictionary got it wrong. Wrong. Wrong!

Other scientific sources say that curcumin was first isolated by Vogel and Pelletier in 1815 and “…its chemical structure was determined by Roughley and Whiting in 1973.” Whatever that means. So far I have been unable to find out anything ‘biographical’ about Vogel. The 1910 Encyclopedia Britannica says that “Paper tinged with a tincture of turmeric exhibits on the addition of an alkali a reddish brown tint, which becomes violet on drying. This peculiarity was pointed out by H. A. Vogel [Aha! it is H. A. Vogel. Now I am getting somewhere – maybe.] in 1815, and since that date turmeric has been utilized as a chemical test for detecting alkalinity.”

I am having incredible difficulty in finding any biographical material about either Pelletier or Vogel. Oh, I have found some, but almost next to nothing and with few dates. At least I did uncover that Joseph Pelletier, son of a chemist, was born born in Paris on March 22, 1788 and died there in 1842 on July 24, age 54. Co-inventor with Joseph Caventou of quinine in 1820. Below is a French postage stamp honoring their discovery. Unfortunately no one has bothered to honor the discovery of curcumin so I don’t know what Vogel looked like. Sad!

There is an interesting connection here: When A. G. Perkin’s father William Henry Perkin was a teenager he studied chemistry with a German scientist who was trying to synthesize quinine. During Easter break – I think it was Easter – W. H. went home and conducted experiments on coal tars in the basement of his father’s house. He failed to synthesize quinine, but he did accidentally discover how to produce aniline dyes. Believe it or not this led indirectly to the chemical industry that gave us such wonder drugs as aspirin. Who would have thought? And yes, for those of you who pay attention to the history of Japanese printmaking, those are the same aniline dyes which brought about such a profound change in print production in the late 19th century.

A Dictionary of Applied Chemistry from 1913 says that Pelletier and Vogel gave curcumin its name. That sounds reasonable. However, the modern Merriam-Webster Dictionary says it didn’t appear in English until 1850. This term they got from the French who first called saffron curcuma in 1559. (Now it refers to turmeric.) And this in turn came from the Arabic via new Latin.

Now, after much digging I may have solved the problem somewhat in the discrepancies between the 1815 and 1842 dates. It was Vogel, Sr. who with Pelletier seems to have isolated curcumin from turmeric. However, it was Vogel, Jr. who in 1842 “…analysed a similar but perhaps somewhat purer preparation, which, however, must have consisted in greater part of the yellow resin contained in the root…” This comes from an 1883 publication.

A. G. Perkin noted that turmeric was used as a dyestuff in ancient Rome.

While I may not be able to show you what ukon yellow looked like on 18th century prints the chances are you know anyway if you have ever eaten curried rice. That lovely bright yellow can be found in spades today in takuan zuke or pickled daikon as photographed by Lyzzy and posted on wikimedia.org.

Now there’s your yellow. Of course, tumeric infusion into daikon during pickling has to be somewhat different than ground up ukon root applied to paper when producing woodblock prints, but I think you get the idea. Before processing the root of the Curcuma longa or domestica – the scientific name for ukon – it displays a much more intensely orange color. If it looks like a ginger root that is because ukon is part of the ginger family. (The image below is by Scops and was posted at wikimedia.org.)

When ground into a powder we get that beautiful but elusive yellow as seen in this picture posted by Elya. Kind of reminds me of those wonderful early sculptures by Anish Kapoor – one of my favorite artists.

While the root is what gives us that deep yellow the rest of the plant is nothing to sneeze at. Shue Suehiro has posted several images of the ukon as it is flowering. He has graciously allowed us to use these. His site can be found at http://www.botanic.jp/index.htm.

In a November 99 article from Current Organic Chemistry it says: “The rhizomes of the Curcuma longa L. (Zingeberaceae) have been known as a medicinal herb since the second millenium BC; the first written account is an Assyrian herbal ca. 600 BC. Its uses include the application of cosmetics, culinary, medicinal and ritual purposes and as a dye.” A related rhizome of ginger is mentioned in ancient Sanskrit, Hebrew and Chinese texts.

The Getty Museum conservation department produced a paper in 1989 on the fading caused by atmospheric ozone. Shielded for 12 weeks from any exposure to light ukon was one of the colorants which faded anyway. This is true of yellow pigments in general when put in contact with contemporary urban ozone conditions, with ozone known as “…one of the most powerful oxidants found in nature.” In June 1988 the Getty along with Cal Tech produced a similar paper, Protection of Works of Art from Photochemical Smog, noted that ukon was among a short list of the most commonly used organic colorants in 18th and 19th century ukiyo prints. They also pointed out that as early as 1888 studies were underway to see if air pollution had an effect on artist’s pigments: “…concern over pollution in the London atmosphere led to a systematic investigation of whether or not direct exposure to the combustion exhaust from a burning gas jet would cause artists’ pigments to fade.”

Ukon which contains curcumin faded more under the test conditions mentioned above than any other colorant.

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