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I looked in many books about Japanese textiles during this holiday. We will introduce some interesting information in the future news letter.
Today, we would like to write about natural ai.
We have written about natural ai more than several times, and most our customers have to know about Japanese natural ai.
In elder times, Japanese people cultivated ai, and dyed their clothes with it. However, dyeing with natural ai is a very elaborate work, and around Meiji period(1910-1920), synthetic indigo was imported, and natural ai was rapidly replaced by it.
Synthetic ai was way cheaper than natural ai, and easy to handle and dye. Its blue color was very similar to natural ai, and ordinary people couldn't tell the difference. It is natural because the molecular architecture of synthetic indigo and the chief component of natural ai are identical.
More about natural ai, please refer John san's page and the page below.
http://www.johnmarshall.to/9-conversations007a.htm
http://www.mukogawa-u.ac.jp/~ushida/e_ai_exp.htm
However, dyer and connoisseurs continue to say that the colors of natural ai and synthetic ai are completely different. Their main affirmations about the difference are
Natural ai is more
1)brightly-colored
2)unequal coloration
3)wash-fastness
4)less bleeding
It must be correct, but we don't have scientific evidence about it, and some people say it is a kind of religion. And we also thought it was difficult to say why they are different.
However, several days ago, I searched in the internet, and found the interesting academic papers! During these past years, I have been searching again and again, but there was no such page. There had to be persons who had similar question as we had, and wanted to evince the difference scientifically and they proved it!
http://www.jstage.jst.go.jp/article/fiber/63/2/P_48/_pdf/-char/ja/
Unfortunately the text is written only in Japanese. It is difficult to translate all text, but we would like to introduce the essentials with figure.
Natural indigo and synthetic indigo are identical, but their connection forms are different. The distance between the two molecules of synthetic indigo is narrower. So the amplitude of the natural indigo is bigger. All differences of natural and synthetic indigo come from this difference.
Both natural and synthetic ai(indigo) are too big to sink into the textile, so they can not dye as they are. To put them into the fabric, dyer removes the bonds of two molecules. Its process is 'reduction', and yellow molecules soluble in water and can sink into the textile(they are smaller than the holes of surface of textile).
After the single molecules sink into the textile, dyer rebuilds the bonds. This process is 'oxidization', and it is simply made by exposing to the air. Molecules become bigger again, and they are difficult to go out from the holes of the textiles('dyed'). Process of natural and synthetic are same, but difference occurs from the size. Synthetic indigo is smaller, so it is easier to get out from the textile(it explains the third aspect above, `wash-fastness'). And from their study, it is understood that molecules of natural ai pair up near the surface of the textile. They say it will explain the first aspect, `brightly-colored') of natural ai.
Because of the amplitude, molecules of natural ai are difficult to move in the textile, so it will be the reason of the fourth aspect above, `soaked less'). Dyers say, to dye the fine patterns with shibori technique, they must use natural ai, because synthetic ai bleeds easily to the not-intended part.
And of course, the second aspect, `the unequal coloration')happens from the same reason.
This paper clarifies long time our question about natural ai.
We hope you enjoy above clarification.
Here is the movie of my twitter friend's. She is the professional dyer, and the movie shows how the Ryukyu ai change by 'oxidization' from green to blue ai color rapidly in the air.
http://ow.ly/P7CD
Please add your comment here! †
- The comment about a mollusk source for indigo is interestingly addressed on the website http://www.tekhelet.com/brochure.htm which discusses the possibilyt that the biblical source of sacred blue (techelet) and purple (argaman) is the mollusc Murex trunculus. The murex may be used to produce both colors depending on the osidation process. Note also that "murex" is quite similar to "murasaki" (Japanese for purple) -- Adina?
- The comment about a mollusk source for indigo is interestingly addressed on the website http://www.tekhelet.com/brochure.htm which discusses the possibilyt that the biblical source of sacred blue (techelet) and purple (argaman) is the mollusc Murex trunculus. \the -- Adina?
- Wow! Thank you! Now I will read more about ai! -- grace?
- I found both your recent newsletters on Indian weaving and dyeing. The Ancient Egyptians were known for their superior cotton .Even today 800 to 1,000 thread count here is very soft and expensive. Ancient celtic people of Scotland and Ireland used woad to dye for blue color also using it to color their skin as war paint. The Romans noted this in Journals on Britannia as they called it. The British used to get indigo from India when it was part of "The Empire" . Native American Indians also had a form of indigo which they traded first with the Dutch then the English. It would be interesting to see DNA break down of woad indigo and ai and I would guess they are related. Keep the interesting articles on fabric and dye comming. Your friend whiterosr929 -- MARION NY?
- Thank you very much Helen san! Of course, we are very happy if you put link to your blog! -- Ichiro
- Thank you. Your explantaion is very clear and fascinating.. The person who tells you that indigo was amde froma mollusc in ht etime of Elizabeth the first is wrong. The source for Indigotin was from Isatis Tinctoria ( woad) . I will put a link to your site from blog I hope that is okay. Many thanks again. -- Helen Melvin?
- Cherie san, Anne san, thak you very much for your comment and interesting information! --
- Leena san, thank you very much for your comment and link from your blog! -- Ichiro
- PS. I posted a link to your site in my blog, http://www.riihivilla.blogspot.com
I hope that was ok. -- Leena Riihelä?
- Thank you very much for the information, and especially in English. I am very interested in natural dyeing in Japan, but unfortunately so little is available in the Internet and in English. Thank you again! -- Leena Riihelä?
- This same process was used in England many years ago, and they used the shell of a specific mollusk to make the indigo. In fact, regal decree made in the time of Elizabeth I the dyers and weavers had to remain outside the walls of the town, and well down-wind of the royal nose! Thank you Ichiro for the wonderful info! -- Anne?
- This same process was used in England many years ago, and they used the shell of a specific mollusk found inthe oceans and the rivers of -- AnneMae?
- Ah, very very sorry, I found an English version of the article and forgot to post that information. See http://www.mdpi.com/1996-1944/2/2/661/pdf . It isn't exactly the same article, but it is very close to the Japanese article. The point seems to be that the molecules of natural and synthetic indigo are the same, but something is causing the natural indigo molecules to "aggregate" but not the synthetic indigo molecules. -- Jeff Krauss?
- Dear Ichiro, Thank you for the explanation above. It is not an incorrect explanation, and gives a good overview of the differences. I really appreciate that you go to a lot of work to educate us. As you are not giving us a scientific education, giving just a clear piece of information like this is just great. Thank you for all the interesting information that you have shared with us during 2009. Happy New Yearn -- Cherie Hoyle?
- Oh! Yes, it must be the English version! I think my simplified explanation is not wrong, though ---- . I understand that 'aggregation' is occured by oxidization -- Ichiro
- Ah, very very sorry, I found an English version of the article and forgot to post that information. See http://www.mdpi.com/1996-1944/2/2/661/pdf . It isn't exactly the same article, but it is very close to the Japanese article. The point seems to be that the molecules of natural and synthetic indigo are the same, but something is causing the natural indigo molecules to "aggregate" but not the synthetic indigo molecules. -- Jeff Krauss?
- Thank you very much for comments! Mmmmmmm, my English seems not to be enough skilled to convey their study ------ -- Ichiro
- Further comment---the article uses the terms "dye aggregation" and "aggregated indigo clusters" without defining them or specifying what is the mechanism that would produce this aggregation in natural indigo. I assume it means that several indigo molecules are somehow physically connected, but I don't understand what physical mechanism might produce this. Anyway, the conclusion is that this "aggregation" causes natural indigo to have poorer penetration into the textile and more dye remains on the surface, compared with synthetic indigo. But the paper does not explain why this "aggregation" occurs. -- Jeff Krauss?
- Please check my blog. My Friend Teresa Kobayashi from Okayama, has permitted me to post pictures of making a natural indigo dyepot. http://indigodye.blogspot.com/2009/10/teresa-kobayashi-indigo-dye.html -- M. Joan Lintault?
- Sorry, but that information is wrong. Synthetic indigo molecule and natural indigo molecule are identical in size. The only difference is that natural indigo contains more colored impurities (indirubin and others) than the synthetic variety. -- Jeff Krauss?
- Sorry, but that information is wrong. Synthetic indigo molecule and natural indigo molecule are identical in size. The only difference is that natural indigo contains more colored impurities (indirubin and others) than the synthetic variety. -- Jeff Krauss?
Original text is written by Ichiro on 3rd Jan 2010.
You can read the original text in this frozen page Ai(Japanese natural indigo)(Original)
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