ORS 359.360: Ownership of physical work of art remains with artist unless expressly transferred.

Whenever an exclusive or nonexclusive conveyance of any right to reproduce, prepare derivative works based on, distribute copies of or publicly display a work of fine art is made by or on behalf of the artist who created it or the owner at the time of the conveyance, ownership of the physical work of fine art shall remain with and be reserved to the artist or owner, as the case may be, unless such right of ownership is expressly transferred by an instrument, note, memorandum or other writing, signed by the artist, the owner or the duly authorized agent thereof. [1981 c.824 §3]