Wool was the most used material in the middle ages.
It could be produced in great quantity, it was warm, it could be made into thin or thick fabric and took dye more easily than other fabrics.
Linen, obtained from the flax plant, was used for shirts and underwear and cotton, introduced by the Moors in the 9th century, was an important export of Spain.
From the East, they obtained silk in brocades, gauzes and damasks, which became very popular for the very wealthy after the Crusades.
They also used animal hides and furs.
Usually, fibres were spun to make yarn.
This yarn was later knitted or braided into a piece of cloth but, by far, the most usual technique was weaving on a loom.
The vertical loom was in use from ancient times and it hasn’t changed in many countries of the world since.
By the 11th century, the device developed into a machine with pulleys.
This made the process much faster.
Weaving, however, was still a domestic thing.
Additionally, wool could also be compressed into felt:
John Hooker, writing about the city of Exeter, in Devon, in 1575, noted that it had once been full of “clothiers and producers of broad cloths, destined primarily for Spain and southern Europe.” In those days, he said, English broadcloth—a densely woven, felted wool cloth—was of such good quality that it was known all over Europe by the name of the town where it was made. By the time Hooker was writing, however, business had taken the place of craftsmanship: Exeter was now full of merchants and shopkeepers, “of whom the merchants are the most prominent and wealthiest.”
The Medieval World, Kathy Elgin
Fixing the colors was difficult and expensive so bright colors were usually reserved for the wealthy, but all the population liked them.
Most processes involved heating and wetting the fabric and mixing with the fermented dye and elements like natural glue, wine, vinegar, salts, bark.
Dyes were obtained from plants (lichen, woad, common madder, saffron…), insects (cochineal, the same we use for crimson now) and minerals.
Make something to make thread of. The most common material is wool and flaxen. Flaxen is grown on the ground, wool is grown on sheep.
Make thread. This depends on the material: if wool, you want it washed, carded (to get the hair roughly in the same direction), drawn and spun to threads. You use ash and fat to make soap to wash the wool, cards to card the wool and a spindle to spin thread.
Start weaving: When you have lots of thread, you make a warp. That’s the thing to the right. It’s lots of threads or yarns mounted on a roll and rolled up, then mounted on a loom.
The pedals are used to raise alternating yarns of the warp to make a gap that you can send the weft through.
The weft is the thing that the weaver holds in his right hand.
After the weft gets through, he raises the other yarns with the pedals and beat down the weft thread to get it tight.
Repeat until you have a long roll of cloth. This is weaving.
There’s one more step: fulling, which is to cleanse the wool (again) and make it thicker.
Basically, you put the cloth in a vat of stale urine and had someone trample around in it.
If you know anyone with the surname “Fuller”, you now know what his ancestor did: his great-great-great-great-great-great-great-great-great-grandfather (or something) Eric the Fuller used to walk on cloth in stale urine.
To get it in color, you dye either the cloth when weaving is done, or if you want a colored pattern, you dye the yarns before it’s mounted on the warp.
You need a dye, a big vat, and kettles to boil water.
Some of the dyes were harder to make than others: purple was incredibly hard and smelly to make that is why it was mostly worn by royalty members .