Are they actually acetates or are they vinyl test pressings?
I thought that an actual acetate (a metal disc, usually aluminium, forming the base and that base covered with a thin black lacquer, usually nitrocellulose) was most commonly either 10" in diameter (for a single) or 14" in diameter (for an LP). I'm no expert on this and there may well be exceptions, but I thought those were the common sizes. The lacquer was often so thin that the needle could wear through the grooves quite quickly, sometimes making the disc all but unplayable.
Anyone know or sure?
Also, in Dylan World, it has not been uncommon for people to "manufacture" a rare acetate, sometimes with seemingly authentic documentation or similar to back upo the claim of rarity, to fool people into buying what purports to be a genuine "rare" acetate that isn't.
I am NOT suggesting that here - not at all. Indeed, the fact that there are discs by a range of artists, some of whom would not be described as collectable, suggest otherwise.