ACEO if sold. ATC if traded. But I do use both at times. My collection includes both, bought work, and traded work. If I go to buy supplies at a rubber stamp shop or want to read up on some techniques in magazines, I have to look for ATC, as ACEO is not being used in general, although I have heard it used at times.
There was a tv show showing someone who 'sold ATCs' on ebay. Never once was it mentioned as ACEO.
It gets confusing.
Sorry I'm not of much help.
~Jillian
~Jillian
artist, Jillian Crider
... google me!