Makeup of the Dead: The History of Corpse Paint
First things first, I think we can all acknowledge that "corpse paint" in the vein of black metal is properly understood to refer to a particular style of facial makeup, that being the type that is deliberately intended to resemble a decaying human body, although allowances are often made for other overtly "evil" intentions such as "war" paint or demonic representation.
"Shock rock" is typically agreed to have been ushered in by the success of Screamin' Jay Hawkins, best known for the immortal hit "I Put a Spell on You". His acolyte, Screaming Lord Sutch, was himself an irregular face paint wearer, but did similarly employ horrific imagery – albeit of a tongue-in-cheek variety – as on his 1963 single "Jack the Ripper".
Probably the most direct antecedent to what would later define the black metal look was England's Arthur Brown, who helped to bridge the gap between shock rock and acid rock in the mid-to-late 60's along with a flamboyant sense of theatricality that made frequent use of tribal masks and black-and-white face paint.
Alice Cooper actually started as a garage rock band before eventually segueing into a sort of proto-metal in the 70's – Cooper never really committed to a particular sound until his decidedly metal resurgence in the mid-80's – but the garish face paint, on stage beheadings and grand guignol vibe were part of his entertainment package from the earliest days.
Heavily influenced by the glam rock sense of showmanship, but eschewing its pop-leaning musical trappings for a beefier rock and roll sound, KISS brought a gringo-ized Japanese Kabuki look to the table, with bassist Gene Simmons' "demon" character exhibiting the most evil look face paint the genre had seen to that point.
The most influential presence in metal face paint history, King Diamond apparently began dabbling in it back in his early days with Black Rose in the late 1970's, although I can't seem to locate any photographic evidence to effect. Either way, though, I don't think anyone disputes his preeminence in setting the bar during his time with Mercyful Fate, who released their first EP in 1982, a year before the thrash explosion that later paved the way for the first wave of black metal bands.
Arguably the single most important figure in all of black metal history even though he was around to see very little of it, the legacy of Per "Dead" Olin looms like a god over the genre. Ostensibly the first man to deliberately utilize face paint to simulate a photo-realistic corpse look rather than an ornamental or cosmetic pattern, Dead furthered the conceit by burying his clothes for days on end in the musty earth to give them a disinterred corpse look.
Finally, bands like Immortal took the colorless, black-and-white look of corpse paint and, combining it with old school metal outfit staples like bullet belts and long spikes, developed a sort of "war metal" look distinct from the purely functional makeup used by other early black metal progenitors.
… and since those halcyon days of the early 90's the style has continued evolving, with some bands adhering closely to the original, realistic corpse look and others looking to put their own stamp on it, the latter of which often leads the wearer further and further down a path of differentiation that can sometimes be indistinguishable for actual cooptation, as in Rob Zombie's band.
However you like your Corpse Paint, you gotta admit, that shit is pretty cool, no matter where it started really.