Purchase of the original work does not include Copyright Assignment. The artist retains complete ownership of all copyright on any and all reproductions of his work. He is the licensor who can instruct a company/studio to reproduce his work in a specific way and if needed, for a limited period of time. Any digital/electronic copies of his work are also within the copyright held by him. The buyer can of course request to purchase the copyright to the finished work for a separate fee, which would also include rights to reproduce the work for sales of prints or merchandise.

The 70 Year Rule for Original Work.
The Artist will remain copyright holder and first owner for the life of the artist plus an additional 70 years. However, copyright is a form of intellectual property – which, just like physical property it can be brought, sold, inherited or passed on to another person or organisation. The Artist may can sell the copyright of an original work to another person for a separate agreed fee, this will be documented in a signed contract which states that the transfer of copyright has taken place - this transfer is called an 'assignment'.