Out of curiosity, what can you do about paintings where the artist is dead or unable to be found?  Is there a point where the owner can sign a release?

If nothing is done legally, everything and anything becomes "public domain" at a certain point as copyrights by default have an expiration date if you take no action to extend them. I've always pointed to this built in expiration date as one reason why IP law is so ridiculous. If you truly owned the idea... there would be no shut off date on your ownership, the law itself admits you can't really own ideas even though the whole reasoning behind the law IS ownership of ideas. I could go on and on with the flaws surrounding the very idea of having IP law, but I suggest reading some books on the subject of abolishing IP laws to better understand why they are fundamentally flawed - and thus cause so much headache for the very people they are often designed to protect people like us. For the record, I actually don't buy into the idea that without IP laws, creativity would suddenly die and stock media wouldn't vanish either - for pure economic reasons, but thats a subject for another day!

The following is the text of Section 27 of the 1909 Copyright Act, which remained in force
until succeeded by the 1976 Act:

The copyright is distinct from the property in the material
object copyrighted, and the sale or conveyance, by gift or
otherwise, of the material object shall not in itself
constitute a transfer of the copyright, nor shall the
assignment of the copyright constitute a transfer of the
title to the material object.

Section 202 of the 1976 Copyright Act (effective January 1, 1978) is equally unequivocal on the subject:

Ownership of a copyright, or of any of the exclusive rights
under a copyright, is distinct from ownership of any
material object in which the work is embodied. Transfer of
ownership of any material object, including the copy or
phonorecord in which the work is first fixed, does not of
itself convey any right in the copyrighted work embodied
in the object; nor, in the absence of an agreement, does
transfer of ownership of a copyright or of any exclusive
rights under a copyright convey property rights in any
material object.

http://www.kauaikeepsakes.com/artists4peace/files/artistrights.pdf

In plain English the artist still owns the copyright. If deceased, the estate owns it. There's a whole bunch more about if it was before 1978 or after and was it ever registered. I know we are more concerned here than most people are about correctly using and adapting materials, but if it was an original work and you own the physical work, and there's no way to find the estate or heir, I doubt if someone would come after you for using it.

Should you be able to find a descendant or estate, you could get a release signed by them. Most people aren't interested in licensing rights and shouldn't be adverse to giving the actual owner of a work the rights to reproduce it. If you pay them one dollar for the rights, it serves as proof of remuneration for the transfer of rights.

I have always been under the impression that if I own an original work of art (not a reproduction or print), then I am the copyright holder and do not need any further permissions from the artist or estate.  It would be nice to find out how art collectors deal with copyright issues when considering reproduction.

I think that in this day and age that the copyright is not likely transfered to who ever owns the original piece. It's a weird situation but is likely this way.  I have purchased original pieces and been told the copyright was not part of the deal.

Peter