We have mainstream media and eager-to-please-greens politicians spouting the need to reduce carbon-this and carbon-that, never realizing that they are talking about the wrong thing. They mean CO2, but out of a plenitude of ignorance shorten "carbon dioxide" to "carbon." One is a molecule mostly found in the gaseous state, the other an element found most often in the solid state. I leave it as an exercise to the reader to determine which is which.
Perhaps the switch in scientific nomenclature is deliberate, because carbon is normally black and dirty, while CO2 is clear and clean. Better to appear to be seen calling for cleaning up that which is black and dirty, than that which is clear and clean.
We are reassured by those in the know that "carbon" is evil, evil, evil, and why hasn't lazy government spent enough on eradicating it yet. Never mind that CO2 is the chemical that allows vegans to remain vegan.
And so it is with that background that an auto blog that I follow made reference to carbon copy:
...focusing instead on building an updated model influenced by the utility vehicle, but not a carbon copy.
Surely some kind of genetic or chemical manipulation must be involved in making a carbon copy, no doubt. I suspect people even in their 40s might not know the meaning of the term.
In the days before computers made trivial the printing many copies of a document, we typed with typewriters. If we needed a copy of a document, such as for a committee meeting, we didn't want to type it over many times. Instead, we used carbon paper -- very thin paper coated with the graphite form of carbon on one side. We placed it between two sheets of paper, and then typed. Presto, two copies for the effort of typing one. Amazing productivity booster.
If we were desperate, we would use three or more sheets of paper, with two or more sheets of carbon paper. But the text would get increasingly fuzzy with each layer of paper, as they spread out the impact from the typewriter heads pounding away.
And so that is how the phrase "make a carbon copy" came to mean making a near-perfect reproduction. No CO2 needed.
PS: You can today still purchase carbon paper, but the embarrassing-to-some word 'carbon' has been removed, and so it is renamed "graphite transfer paper." Graphite is carbon, as is diamond. But you knew that.
PPS: Carbon paper would help detectives in 60s tv shows solve crimes, after the bad guy's secretary threw used carbon paper into the trash can, leaving a perfect copy of the incriminating letter for detectives to discover.
PPPS: If you were cheap like me, you would reuse carbon paper until it no longer could make reasonable facsimiles. From facsimiles we got the word 'fax,' which became the next generation of document copying. But then you knew that, too.
PPPPS: Because we couldn't edit letters when we wrote them (without rewriting them, and who wants to do that), the post script (PS) method was devised to add more material to letters to which we already had affixed our signatures.