When Levi’s declares their jeans “the original,” they’re telling the truth. The company invented the modern blue jean—in which rivets reinforce stress points—in 1873. “Levi’s is the father of all of us,” says Imogene + Willie cofounder Carrie Eddmenson. “We have major respect for them.”

Jeans were originally called “waist overalls.” The term “jeans” originated in the Italian town of Genoa, where soldiers wore clothing made from a tough, durable, blue-dyed fabric called fustagno genovese. By 1960, the name derived from this tongue-twisting Italian term was common enough for Levi’s to use it in an advertisement for its denim.

And while we’re on the topic of word origins, “denim” is a derivation of a French wool/silk blend called Serge de Nimes, which originated in the 17th Century.

In case you were wondering, acid wash jeans are created by washing normal denim in an industrial machine loaded with permanganate-soaked pumice. When Carrie was a teenager, part of her job at her family’s denim company was loading permanganate rocks into the washing machines. People who go by the DIY method use chlorine, which is how it was done in the early days of acid washing.

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Shrink-to-fit jeans typically lose one to two inches in the waist and three to four in the inseam the first time they are washed. (Don’t worry: if you’re caught in a rainstorm, you should be fine, although they may turn your Jack Purcells blue.) The shrinkage is a result of the untreated cotton fibers’ natural reaction to moisture and drying.

Sanforizing, a process first used widely by Wrangler, reduces shrinkage rates from 5-10 percent to less than 1 percent by slightly moistening, stretching, shrinking, and drying the denim prior to sewing it into the finished product.

Distressing is typically done via a combination of washing and manual treatments. General fading—think light blue jeans—is achieved through multiple washes. Localized fading—e.g., whiskers at the crotch, honeycombs at the knees, small holes—is usually done with sandpaper and oftentimes by hand. These laborious processes can raise the cost of a pair of jeans significantly, as a highly (and skillfully) distressed pair can go through hours and hours of treatments. “We take this to a whole other level: We mold, hand-sand, and pigment every pair in our Nashville store,” says cofounder Matt Eddmenson.

Befitting their workwear origins, jeans were originally made with a back cinch to adjust the waist. During WWII, the cinch was eliminated to save fabric and hardware. It never returned to its prior prominence after wartime restrictions ended, though it’s starting to see a comeback as part of the current renewed interest in heritage style. (If you’re interested in having a pair of buckle-backs to call your own, check Matt’s original pair.)

Those colorful edges, often red or orange, that appear when you turn up the cuff of your jeans? They’re a hallmark of selvage denim—derived from the phrase “self edge”—which is woven on a narrower shuttle loom with a continuous cross-thread. For denim geeks, selvage is the baseline of quality, same as extra virgin olive oil is for chefs. You start there and go upward.

Most of the shuttle looms that produced early American denim have resided in Japan since the 1980s, and many believe  that Japan, not America, now produces the best in the world. Matt and Carrie, however, choose to make their jeans with fabric made at Cone Denim in North Carolina. It was one of the first mills to produce fabric for Levi’s and is generally acknowledged as one of the best.

The rise on a pair of jeans refers to the measurement from the crotch (where the four corners of the seams meet) to the top of the waistband, and when you hear people talking about the rise, what they typically mean is the front rise. After several years of lower—sometimes disarmingly lower—rises, a more traditional mid-rise is starting to creep back into fashion.

Originally, boot cut jeans were called “cowboy cut,” and were slim though the seat and thigh with enough room—but only just—to accommodate, at the hem, the shaft of a cowboy boot. But enough of the history lesson. Unless your day job involves spurs and lassos a slim- or straight-leg fit is the best call. “Even in Nashville, we’re teaching these cowboys that straight is best,” says Carrie. “And you can get a boot under a straight-leg jean: All the original cowboys did.”

White denim is perfectly acceptable all year-round, especially if it’s the name of your band.

Denim can be woven multiple ways. The most common type is right-hand twill, in which the twill lines of the denim rise diagonally from one side to another. This is also considered the most rugged weave, as the direction of the weave reinforces the twist of the fibers being woven, thus “closing” them. Left-hand denim reverses the direction of the twill line and has a softer hand than right-hand twill because the weave opposes the twist of the threads, opening them up slightly. Broken twill, meanwhile, switches between these patterns throughout the process of weaving, creating denim without the defined diagonal twill lines common to the fabric.

Denim weight is determined by measuring the heft of a yard of fabric—this is, incidentally, true of all textiles—so those 14 oz. bad boys you’re wearing actually weigh significantly more than an extra-large burger. “We feel—and customers confirm—that 12 oz. can sometimes be a little flimsy,” says Carrie. “Anything over 14 oz. becomes a competition between aficionados, comparing whose jeans weigh the most. We think that settling in the 13 oz. range is the best bet for all-year-round wear.” Even when it’s sweltering? Luckily, many jeans companies now produce options in featherweight, 6 and 8 oz. denim (though 10 oz. options will do just fine in a pinch).

Lee introduced the first zip fly jeans, the 101Z, in 1926, nine years after the patent was issued on the modern zipper. Because Lee was the primary source of jeans on the East Coast, the buying public became accustomed to the style. On the other side of the States, Levi’s stuck with the standard button fly that had historically been the only option. That is, until 1954, when the label introduced the 501Z, a zip-fly version of their flagship jean, in a bid for a slice of the Eastern market.

During WWII, Levi’s was forced to remove their “arcuate” stitching from the back pockets of its jeans, as the thread was functionally unnecessary and needed elsewhere for the war effort. To keep this signature detail despite the declarations of the War Production Board, Levi’s sewing machine operators hand painted the design on the pockets of each pair of jeans until thread restrictions came to an end.

(Spotted at Park & Bond)