This seems to explain it.
What is Copyright?
Much of the information you will find in our “Copyright Basics” sections has been adapted from information found on the official website of the U.S. Copyright Office; see “Links” to go directly to the Copyright Office’s site for additional, more detailed information.
Copyright is a form of protection provided by the laws of the United States (Title 17, U.S. Code) to the creators of “original works of authorship,” including literary, dramatic, musical, artistic, and certain other intellectual works. This protection is available for both published and unpublished works. Section 106 of the 1976 Copyright Act generally gives the owner of copyright the exclusive right to do and to authorize others to do the following:
To reproduce the work in copies or phono records;
To prepare derivative works based upon the work;
To distribute copies of the work to the public by sale or other transfer of ownership, or by rental, lease, or lending;
To perform the work publicly, in the case of literary, musical, dramatic, and choreographic works, pantomimes, and motion pictures and other audiovisual works;
To display the copyrighted work publicly, in the case of literary, musical, dramatic, and choreographic works, pantomimes, and pictorial, graphic, or sculptural works, including the individual images of a motion picture or other audiovisual work; and
In the case of sound recordings, to perform the work publicly by means of a digital audio transmission.
In addition to copyright, certain authors of works of visual art also have the rights of attribution and integrity as described in section 106A of the 1976 Copyright Act.
It is illegal for anyone to violate any of the rights provided by the copyright law to the copyright holder.
Who Owns Copyrights?
Copyright protection subsists from the time the work is created in fixed, tangible form. The copyright in the work of authorship immediately becomes the property of the author who created the work. Only the author or those deriving their rights through the author can rightfully claim copyright.
In the case of works “made for hire”, where an artist has created the work while in his/her capacity of employee, the employer and not the employee is considered to be the author and copyright holder. Where a work was created jointly by more than one artist, the authors of a joint work are all co-owners of the copyright in the work, unless there is an agreement to the contrary. Copyright in each separate contribution to a periodical or other collective work is distinct from copyright in the collective work as a whole and vests initially with the author of each contribution.
The mere ownership of a book, manuscript, painting, or any other work does not give the possessor of that work its copyright. The law provides that transfer of ownership of any material object that embodies a protected work does not of itself convey the copyright or any interest in the copyright. This remains in the possession of the creator and is often referred to as the underlying artist’s copyright, distinct from the physical object with embodies it.
Any or all of the copyright owner's exclusive rights or any subdivision of those rights may be transferred to another party, but the transfer of exclusive rights is not valid unless that transfer is in writing and signed by the owner of the copyright or such owner's duly authorized agent. Such transfers are comparatively rare in the U.S. and are almost never knowingly engaged in by European artists. For more on this subject, go to “Related Topics” and see the pages titled “Do U.S. Owners of Works of Art Also Control the Copyrights?”
How Long Is a Work Copyright-Protected in the United States?
Works created on or after January 1, 1978: A work that is created (fixed in tangible form for the first time) on or after January 1, 1978, is automatically protected from the moment of its creation and is given a term of copyright protection enduring for the lifetime of the artist plus an additional 70 years after the artist's death. In the case of "a joint work prepared by two or more artists who did not work for hire," the term lasts for 70 years after the last surviving artist's death. For works made for hire, and for anonymous and pseudonymous works (unless the artist's identity is revealed in Copyright Office records), the duration of copyright will be 95 years from first publication or 120 years from creation, whichever is shorter.