# Why are blue jeans blue? **URL:** \ **Category:** Factual Questions\ **Created:** [January 21, 2004, 3:48am UTC](https://boards.straightdope.com/t/why-are-blue-jeans-blue/225416 "2004-01-21T03:48:16Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![pezwookiee](https://avatars.discourse-cdn.com/v4/letter/p/9d8465/32.png) [@pezwookiee](https://boards.straightdope.com/u/pezwookiee)\ **Post date:** [January 21, 2004, 3:48am UTC](https://boards.straightdope.com/t/why-are-blue-jeans-blue/225416/1 "2004-01-21T03:48:16Z")
Who decided that wearing blue pants is normal? – But only if they’re made out of denim. (Navy blue dress pants don’t count.) ---
**Author:** ![stuyguy](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@stuyguy](https://boards.straightdope.com/u/stuyguy)\ **Post date:** [January 21, 2004, 4:12am UTC](https://boards.straightdope.com/t/why-are-blue-jeans-blue/225416/2 "2004-01-21T04:12:55Z")
Blue jeans go back to Levi Strauss who made his first pair out of tent canvas around the time of the California Gold Rush (c 1849). IIRC, his fabric was dyed with indigo, one of the few cheap, colorfast dies available in that day and age. Indigo, BTW, was a major crop in the southern US. That’s why they were blue. ---
**Author:** ![Larry\_Mudd](https://avatars.discourse-cdn.com/v4/letter/l/f14d63/32.png) [@Larry\_Mudd](https://boards.straightdope.com/u/Larry_Mudd)\ **Post date:** [January 21, 2004, 4:36am UTC](https://boards.straightdope.com/t/why-are-blue-jeans-blue/225416/3 "2004-01-21T04:36:34Z")
Additionally, market forces shaped the evolution of “blue jeans.” Levi Strauss & Company initially made their blue jeans (then called “Waist overalls”) available in two types of fabric-- Duck, dyed brown, and denim, dyed blue. The denim proved to be popular, but the duck didn’t sell well at all, and was soon discontinued as unprofitable. ---
**Author:** ![Ostrya](https://avatars.discourse-cdn.com/v4/letter/o/35a633/32.png) [@Ostrya](https://boards.straightdope.com/u/Ostrya)\ **Post date:** [January 21, 2004, 4:57am UTC](https://boards.straightdope.com/t/why-are-blue-jeans-blue/225416/4 "2004-01-21T04:57:10Z")
Not meaing to hijack, but the question I have seems fitting to pose here. What exactly is denim made of? Is it an exclusive blend of cotton? Also, I recently learned that U.S. paper currency contains mostly denim. Is this true? Can anyone comment or cite some info? ---
**Author:** ![racinchikki](https://avatars.discourse-cdn.com/v4/letter/r/eada6e/32.png) [@racinchikki](https://boards.straightdope.com/u/racinchikki)\ **Post date:** [January 21, 2004, 5:29am UTC](https://boards.straightdope.com/t/why-are-blue-jeans-blue/225416/5 "2004-01-21T05:29:51Z")
Denim is made of cotton. If you want to you can put something else in it and it’ll still be called denim, but properly denim is a twilled cotton fabric. (Twill is a type of weave which results in the appearance of diagonal lines across the fabric.) Specifically, denim is usually made with mostly colored threads, but some of them are white, which is what causes the distinctive color pattern which is emphasized with age. I have a pair of “stretch denim” jeans which are 99% cotton and 1% spandex, and they are not twilled, however. ---
**Author:** ![GuanoLad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guanolad/32/42_2.png) [@GuanoLad](https://boards.straightdope.com/u/GuanoLad)\ **Post date:** [January 21, 2004, 6:26am UTC](https://boards.straightdope.com/t/why-are-blue-jeans-blue/225416/6 "2004-01-21T06:26:09Z")
Didn’t Levi Strauss also write the song “Oh My Darling Clementine”? Or was that Huckleberry Hound…? ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [January 21, 2004, 7:08am UTC](https://boards.straightdope.com/t/why-are-blue-jeans-blue/225416/7 "2004-01-21T07:08:53Z")
Where I was raised, farmers all wore blue denim, bibbed overalls. Railroad locomotive crews wore blue and white stribed denim overalls. Sort of like uniforms. Auto mechanics mostly wore blue and white striped denim coveralls. Our two blacksmiths both wore blue bibless overalls (now called jeans), blue shirts and a leather apron to ward off sparks. ---
**Author:** ![bienville](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@bienville](https://boards.straightdope.com/u/bienville)\ **Post date:** [January 21, 2004, 7:23am UTC](https://boards.straightdope.com/t/why-are-blue-jeans-blue/225416/8 "2004-01-21T07:23:17Z")
What if Michael Penn were Romeo in black jeans? Or Heathcliff, for that matter? (Maybe she’s just looking for someone to dance with.) ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [January 21, 2004, 12:07pm UTC](https://boards.straightdope.com/t/why-are-blue-jeans-blue/225416/9 "2004-01-21T12:07:41Z")
> [@greenfingers](#): > > Also, I recently learned that U.S. paper currency contains mostly denim. Is this true? Last I heard, US paper currency contains _linen_, which is a cloth fiber drived from the flax plant and not cotton at all. But they might have changed that in recent years. ---
**Author:** ![SpoilerVirgin](https://avatars.discourse-cdn.com/v4/letter/s/4491bb/32.png) [@SpoilerVirgin](https://boards.straightdope.com/u/SpoilerVirgin)\ **Post date:** [January 21, 2004, 6:52pm UTC](https://boards.straightdope.com/t/why-are-blue-jeans-blue/225416/10 "2004-01-21T18:52:30Z")
According to the [U.S. Treasury](http://www.ustreas.gov/education/faq/currency/production.html#q2), our currency is 75% cotton and 25% linen. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [January 21, 2004, 6:58pm UTC](https://boards.straightdope.com/t/why-are-blue-jeans-blue/225416/11 "2004-01-21T18:58:02Z")
[Crane & Co.](http://www.crane.com/about/default.asp) uses millions of pounds of denim to make US currency paper. On [this page](http://www.crane.com/SpecialtyPapers/Currency/marathon.asp) they also say that they use flax and linen. AFAIK, US currency paper is 100% cloth-based with no wood pulp as used in regular paper.