Seemingly a newly-erected category, its borders are not sharply defined. The only definitive statement that can be made is its between the Bronze-Age and the Modern age of comics. At least one site implicates "Batman:The Dark Knight Returns" and "Watchmen" as being the beginning of the Copper-Age. The 1984 date can be justified due to "Crisis on Infinite Earths". However, I have yet to see two dating schemes agree. The following estimates of its duration have been found:
- 1982-199? Implication of Overstreet PG 2006's cover gallery. Note that a 1982 cover is associated with Copper, while a 1983 cover is associated with Bronze. OPG doesn't explicitly define the age.
- 1984-1992 http://www.boneville.com/2006/09/09/comics-pop-culture-museum-opens-in-baltimore-md/
- 1986-? implication of http://en.wikipedia.org/wiki/American_comic_book from Modern Age description
What's not subject to dispute is that this era is distinct from the speculator's market of the early 90s. It is marked by a proliferation of Indie publishers, especially in black and white formats.
The formation of Image could be said to end the Copper Age.