Not Your Grandfather’s Blue Jeans.

Courtesy Lauren A. Badams.

Courtesy Lauren A. Badams.

A team of scientists from the U.S., Belgium, Portugal, and the U.K. have pushed back the first use of Indigofera tinctoria as blue fabric dye in the world to South America 6,200 years ago. The previous oldest physical specimen was from Egypt 4,400 years ago, although there were written references to blue dye going back 5,000 years. The blue dyed cotton fabric was discovered in an archaeological site that has been studied for many years, Huaco Prieta, located in the northern coastal region of modern Peru.

Publication of the study by Jeffrey C. Splitstoser and his colleagues in Science Advances this month has set off wisecracks in popular science publications about Andean Indians inventing blue jeans, but it is a much bigger deal than that. Besides, what was new about blue jeans was the rivets, not the color.


Indigo blue was highly prized long before the Americas were “discovered.” The ancient Greeks understood India to be the source of the dye and indigo—along with spices and silk—made up the trade goods the Europeans were seeking when they got sidetracked by Aztec and Incan gold.

Why is it a big deal that indigo appears in South America long before Asia or Africa? If the dye required nothing but mashing up something blue, then it might be found everywhere the plant grew, but it’s a bit more complicated than that.

Most ancient dyes were fairly simple. Flower petals were boiled to make them yield up their color. Ochre yielded reds and yellows, depending on the exact iron content. A bright white dye can be extracted from milkweed.

The first difference indigo presents is that the dye is not in the flowers. It’s in the leaves. To make the leaves yield the color, they first have to be fermented. The fermented solids are then dried. The fermented and dried indigo is light and easy to ship.

The indigo solids must then be treated with an alkaline substance, commonly urine, to produce a dye that is apparently white. Yarn treated with the reconstituted indigo comes out white but then turns to yellow, to green, and finally to the deep blue that makes the dye so valuable.

In an interview with Live Science, Splitstoser speculated, “This was probably a technology that was invented by women.” He noted that women were typically in charge of weaving and dying in Andean cultures.

The discovery at Huaco Prieta adds another example of cultural knowledge either purposely destroyed or ignored out of arrogance by conquistadors who believed they were doing God’s work in destroying non-Christian cultures. That destruction fed the myth that Europe represented science when the Americas represented superstition.

These people who were burning Mayan writings and destroying works of astronomy and mathematics and chemistry were burning human beings for heresy at the same time. Indians had science and Europeans had superstition. It ought to be possible to compare cultures in a more objective manner than the settlers have chosen when they wrote all the histories.

Full article here.


  1. kestrel says

    Ha! That’s pretty fascinating. I think there are plants here in the Southwest that will yield blue dye the same way but these days are rare and probably endangered.

    How you could look at the weavings these people did and conclude they were “primitive” is beyond me. Their weaving techniques and braiding techniques are really amazing. Interesting article concerning weaving, probably not the most accurate site but the article is good and so are the pics:

    Their braiding techniques were pretty awesome too. They are similar to the Japanese kumihimo techniques, but with no tools! The Japanese use a sort of stool and weights; the people in the Andes just used their hands. Amazing.

  2. says


    How you could look at the weavings these people did and conclude they were “primitive” is beyond me.

    It wasn’t a true declaration, or belief. Colonial forces always managed to collect a great amount of such goods before they got on with wiping people out. Such items were cherished and highly valued. Of course, the value increased greatly once you killed off 98% of the people who produced said items.

  3. kestrel says

    That is a good point.

    Here is the weird thing (to me). I have a book on sling braiding techniques and here is a sentence from a section titled “The Braiding Mystery”: “How the ancient Peruvians actually managed to produce the complex, richly varied braids found in their slings has long been an elusive secret.” And yet, these slings are produced every day by the Peruvians… and no one thought to ask them?!!! WTF?! It’s definitely not an “elusive secret” to them!

    I’ve also heard such things referred to as a “lost art”. Um, NO. Again -- why not ask?

    Now I have to go punch a pillow or something. That aggravates the shit out of me.

  4. Pierce R. Butler says

    Consider also the literal tons of fine metalwork melted down by the Conquistadors for convenience of shipping as bullion.

  5. rq says

    I love the colour blue. Can we make it a girl colour now, too?* :D After all,

    Splitstoser speculated, “This was probably a technology that was invented by women.”

    So there!
    -- Not Your Berry Picker

    Thanks for sharing this, Caine! Love learning something new.

    * Actually, abolish all genderization of colour.

  6. says

    The indigo solids must then be treated with an alkaline substance, commonly urine, to produce a dye that is apparently white.

    German has the expression “blau machen”, “make blue”: skip work or especially school. It stems from the times when the workers who dyed the fabrics would drink lots of beer some days to produce enough pee. Of course they didn’t do much else those days…

  7. stellatree says

    What kestrel said about “primitive”. That’s a word we could throw out.
    It’s amazing how well preserved that fabric is, and that you can still see the blue! I don’t think indigo is a very stable dye. It must have been so vivid 6200 (!) years ago. I get such sense of awe seeing ancient crafts like these, it is impossible not to imagine the person who made them.

  8. Crimson Clupeidae says

    Giliell, is the origin of the German phrase to be drunk (Ich bin blau) also related to that? I always wondered.

    I love the German language. I suck at actually speaking it, but I learned so much when I lived there that wasn’t taught to me in school….

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