A reader sent me this example of the incorrect use of dying for dyeing:
This term [technicolor] was coined by the company of the same name, and the trademarked term described the company’s process of dying film to create a color print from black-and-white originals, replacing the time-consuming hand-coloring method.
Mixing up the verbs dye and die and their participles dyeing and dying in modern English is comical, but before the nineteenth century, the spelling distinctions were not always observed. For example, in his dictionary (1755), Dr. Johnson (1709-1784) spelled the words for both meanings as die. Joseph Addison (1672-1719), on the other hand, rendered both words as dye.
Nowadays, however, the spellings die and dying are reserved for the sense of “cease/ceasing to live,” while dye and dyeing have to do with coloring or staining something.
The words are often the source of punning. For example, the headline, “Dyeing to Succeed” refers to dyeing one’s hair in the attempt to overcome age discrimination in the workplace.
A common expression with the word dye is “dyed-in-the-wool,” meaning “unchangeable in one’s feelings or beliefs,” for example,
Never ever get involved with a dyed-in-the-wool feminist.
Fran Klein, a dyed-in-the-wool Democrat, voted for Barack Obama in 2008.
Frederick Douglass [said] “I am a Republican, a black, dyed-in-the-wool Republican…”
I am a dyed-in-the-wool, diehard, 1000-percent Trekkie, and I say Trekkie, not Trekker, and I don’t care what the nomenclature has become. –Akiva Goldsman
The expression comes from the fact that when dye is applied to a substance in its raw state, such as wool before it is spun, the resulting color is deeper and more lasting.
The dyeing process produced another expression, more commonly heard in earlier times, but not entirely defunct: “scoundrel of the deepest dye,” meaning, “an out-and-out rogue.”
You have proved yourself a scoundrel of the deepest dye, by maliciously interfering in matters which do not in the least concern you, to the detriment of some of our citizens.” –from a letter addressed to Hamilton Wilcox Pierson (1817-1888)
The man with the good personality may be a scoundrel of deepest dye, and the one with no personality may have the strongest character of the lot. –from a handbook for Christian missionaries (1954)
At other times, when he [Rudolph Valentino] portrayed a scoundrel of the deepest dye, he was made up to look quite repellent –from a 2003 feature in The Guardian
The distinction between die/dying and dye/dyeing is firmly established in modern usage, so you will want to avoid such gaffes as, “When did Eminem die his hair black?”