Part 1 covered blue, black, red, yellow, and green. Let's look at some others.
Gray was a humble color, and could be had by using leftover dye from making black. Cistercians and the Friars Minor of the Franciscans wore gray habits.
Pink was easy to make, since madder root used for red or brazilwood could be used in a lesser strength or by soaking the cloth for a shorter duration. Medieval illustrations often show ladies wearing pink dresses, which makes one wonder if pink was considered a feminine color centuries ago. Men also could be painted in pink, but their hosiery, not upper/outer wear. (By the way, the name brazilwood comes from a Portuguese word, pau-brasil, a flowering plant in the Old World. When Portuguese sailors found a related species growing all over the coast of South America, they named the place Terra do Brasil, "land of brazilwood." That's right: the country was named for the plant, not the other way around!)
If you wanted to suggest purity or innocence, you went for white. This was not always a bright white, but linen looked white enough prior to dyeing that it qualified as white. You could also soak linen in lye made from wood ashes, and throw in some lime. Since clothes could get dirty, wearing white was a sign that you afford to not get "down in the dirt" as a farmer. In the 14th century poem Piers Plowman—in which we happened to find the earliest reference to a "Robin Hood"—of all the characters introduced, there are few descriptions of their appearance, except when white clothing is mentioned; it always indicates a person of purity or innocence.*
Brown or russet/orange came in many shades and can be produced by anyone with access to boiling water and walnut shells or bark.
And so we come to purple, the color of royalty; so much so, that the phrase "born to the purple" indicated royalty, and porphyrogenitus was used in Byzantium as a title. Expensive purple candles were reserved for Advent, the "coming of Christ the King." Dressing a king's favorite in purple, as Edward II did for Piers Gaveston, was a clear indication to all the court of the king's favor. A species of sea snail (Murex) was an ancient source of the color, but it took thousands to make 1 gram of purple dye. Its expense made it rare, and its rarity gave it value, and its value made it reserved to the wealthy and ultimately limited to emperors and the highest classes.
There has been lots of research into the history of dyes. Although I do not quote from it, the Innsbruck Manuscript of 1330 (translated here) has instructions on dying. Vassar has a bibliography on works on dyeing. And there are many websites devoted to medieval times that instruct on dyeing the old-fashioned way. For instance, the illustration above is found on one such site.
In the paragraph on gray, I looked for a link to explain the Cistercians, and discovered that I have mentioned them many, many times, but there's no "introduction" to them. Let me correct that next time.
*A little trivia about me: "Clothing Imagery in Piers Plowman" was one of the first papers I ever wrote in grad school in the Medieval Studies program at UConn-Storrs.