Nineteen-sixty something to nineteen-seventy and a bit
Even bell-bottoms, which were not exactly marketed to cowpokes wandering the lonesome prairie, came home from the store as hard as iron and a deep, evening-sky indigo. It took a good year of wear and washing in very hot water to get them moving toward the proper pale blue. During which time you looked silly. Wearing dark blue jeans looked silly in 1969. Really. Stay with me here.There were few shortcuts to a truly superlative fade. Legend held that cigarette ash helped — and, anyway, flicking a nugget of hot ash into your palm, rattling it like dice and slapping it onto the thigh of your jeans was a gesture of pure juvenile delinquent chic. And, yes, if you were the sort of person concerned about the fade of your bluejeans, you most certainly smoked.
If an out-at-the-knees (or an out-at-the-ass) look was desired, you could take yourself for a drag and a scrape along a roadway or sidewalk, face up or face down depending on the intended pattern of wear. Sandpapering, however, was cheating and strictly frowned upon.
Denim is what it is because the weft is dyed a deep blue, and the warp is a heavier thread that doesn't hold the dye as well. It ages differently from other fabrics. Not only do the dyes fade, but the weft abrades more readily, leaving a wear pattern that is mottled with flecks of white, but dark at the seams.
The most desirable jean of all was an all-over, even pale blue with no holes or patches. It took years of patient nurturing to reach maturity followed by, all too often, a swift decline.
On patches
Patches didn't completely ruin the coolth of jeans, provided a few simple fashion rules were observed. First, patches had to be sewn on (those utilitarian stiff iron-on things were way too 4-H Club). And made out of some kind of especially groovy natural fabric, like contrasting denim, red bandanna, gingham or drapery fabric. As for placement:
Knees, butt: Most common, perfectly acceptable.
Thighs, calf: less usual, less desirable.
Triangular inserts to make straight-legged jeans into bell-bottoms: judgement call. If done right, very cool. If done wrong, very lame.
Crotch: never! Blowout the crotch on a pair of jeans, and out they go. You don't want to be drawing stares to your parts, and you sure don't want anybody wondering what sort of toxic crotch fumes you're giving off that can eat right through Mister Levi's best workwear.
Overt holes in jeans didn't become popular until much later.
Later in the seventies...
I have this memory of my cousin getting ready for a date by sitting in a steaming hot bath wearing dark blue, brand new, straight-legged cotton Levi's. So they'd dry skin-tight, you see. Which must have been the style that led with horrible inevitability to...
Late seventies, early eighties
Jordache. Gloria Vanderbilt. Polyester. Stretchy. Fancy stitching on the pockets. Disco. Stayin' alive. Turn the page. TURN THE PAGE. For the love of god turn the page...
Well, finally
Through all those dark days, a few of us dedicated, lonely souls clung to our cotton jeans. All our cotton clothing, really. It seemed that everything everywhere was tainted with the shame of polyester. This is when I learned to shop at the Salvation Army -- the last shop in America to sell cotton shirts (not counting LL Bean, who also got a big boost about this time). Of course, it's because they were selling 20 year old clothing.



I don't know if this one's still in (I surely hope not), but the last
I checked jeans technology, they were doing a thing called a caramel
wash. It's a jean that's mostly dark blue, but with distinct patches of fade on the upper thighs, and the faded areas are overdyed a brownish yellow.