There is quite an exhastive treatment of copyright issues on the net, as
there seems to be some interest
here is a brief escerpt of what I believe to be the pertinenet info:
"With these concerns in mind, here's a short analysis of copyright
duration.
Generally, for works created in 1978 or later, a copyright lasts for
fifty years beyond the life of the work's author, after which it lapses
into public domain. 17 U.S.C. 302(a). If the work is prepared by two or
more authors (a "joint work"), its copyright lasts for fifty years after
the last surviving author dies. 17 U.S.C. 302(b). For anonymous and
pseudonymous works, and for works made for hire, copyright exists for 100
years from the date of creation, or 75 years from the date of first
publication, whichever comes first. 17 U.S.C. 302(c). No renewal is
necessary or permitted. (The year 1978 in this paragraph is because
January 1, 1978 is the date on which the Copyright Act of 1976 took
effect.)
For works to which the attribution right and integrity right apply (see
section 2.1), these rights endure only for the lifetime of the author.
17 U.S.C. 106A(d).
For works published in the years 1964 through 1977, copyright lasts for
75 years from date of publication. 17 U.S.C. 304(a). In the past,
copyright lasted only for 28 years, unless a renewal was filed with the
Copyright Office. Such a renewal obtained an additional 47 years of
protection. Renewal was made optional in June 1992 by P.L. 102-307, 106
Stat. 264. (The year 1964 comes from the fact that renewal was made
optional in 1992, and 1992 minus 28 (the length of the first copyright
period) equals 1964.)
For works published in the years 1904 through 1963, the copyright lasted
for 28 years from date of publication; if the copyright was not renewed,
it lapsed, and the work went into the public domain. Another 28 years of
protection could be obtained by filing a renewal, for a total term of 56
years (1906 comes from the fact that the U.S. effectively switched to a
47-year second term in 1962, and 1962 minus 56 (the old maximum duration
of two 28-year terms) equals 1906). If the copyright was not renewed
after its initial 28-year term, the work lapsed into public domain.
Generally, all copyrights secured in 1917 or earlier lapsed at the latest
in 1992 and are now in public domain (1992 (last year) minus 75 equals
1917). Copyrights secured in the period 1918 through 1949 continue to
exist only if they were renewed, and expire in the period 1993 through
2024.
Finally, just to complicate things: if the work was created but not
published prior to 1978, its copyright duration is calculated as if it
had been created on January 1, 1978, and lasts as long as that
calculation specifies, or through 2002, whichever is later. If the work
is published in 2002 or earlier, then the copyright lasts as long as that
calculation specifies, or through 2027, whichever is later 17 U.S.C.
303.
Phew! And I thought that there wouldn't be much math in law."
For a lot more information, set browser to:
http://www.cis.ohio-state.edu/hypertext/faq/usenet/Copyright-FAQ/top.html
Rand
M Rand Carlton
mrand@snowcrest.net
Photography...
"The process is
the product"