Originally, jeans were dyed with the color of the actual indigo plant.
Today, natural indigo jeans can’t be considered metaefficient because they are expensive and only available as a kind of designer jean. Notwithstanding this, people admire these jeans because of their distinctive, deeply hued appearance. The story behind them is interesting too.
Almost all blue jeans are chemically dyed these days. Unfortunately, chemical dyeing usually involves toxic fixing agents and heavy metals. Yet, even clothing produced with organically grown fibers using “low impact” dyes, requires the same toxic fixing agents. Here, “low impact” means the dye is absorbed better and chlorine is not used for bleaching (usually hydrogen peroxide is used).
So what did people do before these processes were even available?
They used plant-based dyes such as indigo and madder. Those natural dyes tended to fade after repeated washings, but that was considered appealing — each piece of clothing took on its own unique character by the variations in color.
Natural indigo is perhaps the oldest dye known — the oldest fragments of cloth are dyed with it. It is a dye known to all cultures of the world. Natural indigo is also one of the “fastest” dyes known. It was the original dye of the “Levi’s” blue jeans, a trademark color for durability.
So, indigo, it seems is quite an efficient natural dye. You can read more about the history of natural dyes here.
I’ll end with a quote from Howies’ web site describing their “Truthster Jeans”:
They don�t make them like they used to. Today there are few products in clothing as industrial as a pair of jeans. Man rarely gets to lend a hand.
But to make a plantation indigo jean, well, that takes time. It also takes lots of highly skilled hands taught over generations in the old ways. Mass production, it ain�t.
Firstly the yarns are �ring-spun�. The process is slower and more labour intensive than the method used today. It uses a longer fibre that results in a yarn that has a characteristic natural unevenness.
Then the yarns need to be dyed: today�s modern jean is dyed using a chemical indigo dye. On most industrial denim, the warp yarns (the threads that go down the length of the fabric) are firstly set out onto a large bobbin, and then put through a huge machine that dips them into 24 baths of dye. The first few baths are usually not indigo at all, but either a black or green reactive dye. The rest are filled with a chemical indigo. This gives the denim its �wash down tone� and accounts for its evenness of colour. However, our natural plant indigo jeans use 100% pure plant indigo: the real thing. The indigo plant is an annual crop cultivated in South East Asia as a family of Polygonum. The leaves used from this plant are harvested in the autumn, to make the indigo dye.
The ring spun yarns used for these jeans are �rope dyed�.
This means that the yarns are hand twisted into ropes (as in the picture) before being dipped into the barrels of indigo dye. They are then squeezed and oxidized by hand when they are still in ropes. After repeating this process over and over again, the ropes have a deep blue colour. The yarns are then separated from the ropes and set out along a warp bobbin so different yarns from different dye batches (and therefore with slight colour variations) are all mixed together. This explains the streaky aspect of the fabric, with streaks of colours ranging from deep indigo purple through indigo blue to indigo green. The depth in the colour of howies plantation indigo jeans cannot be achieved without the use of the pure indigo. The denim is then woven on vintage shuttle looms. These old rickety shuttle looms can only make cloth about 30 inches wide, whereas modern projectile looms can make fabric 70 inches or even wider. Wider is cheaper but not necessarily stronger or better.
Over the years these jeans will change colour and develop their own character, as the uneven ring spun yarns are brought to life, and the natural plant indigo slowly fades. As you�d expect all this makes for a true authentic jean but also a pretty expensive one. Indeed, they cost about 10 times as much to make.