My practice is not exclusively, or even primarily, focused on copyright, but interesting developments and issues seem to pop up in this area more than they do in the more quotidian areas of my work. Nevertheless, they have implications for smaller businesses that bear pondering (and getting advice).
Here's one that can help illustrate both the pitfalls and the opportunities presented by the niceties of copyright law. As this article reports, Harold Lloyd Entertainment (HLE) has made a tidy sum over the years licensing other to the iconic image of Lloyd dangling from the face of a clock in his classic 1923 silent comedy Safety Last. Because the film was released in 1923 and not 1922, it remains in copyright under the numerous extensions to copyright term since enactment of the 1976 Copyright Act* HLE has licensed the rights to make "derivative" works of this image to the producers of Back to the Future and Hugo, among others, pursuant to which those films contained scenes of people dangling from clocks.**
This right to make derivatives is a curious aspect of copyright law introduced by the 1976 Act (there were more limited provisions in earlier enactments). A "derivative" of a copyrighted work is something that transforms it from one medium to another, or otherwise "translates" it, either literally or figuratively. The right to create (and therefore to license others to create) derivatives sits in uneasy company with the fundamental principle of copyright law that copyright protects expression rather than ideas. To preserve this distinction, courts have for the most part interpreted the derivatives right fairly strictly so that a challenged work has to hew fairly closely to the manner in which the original idea was expressed before a court will say it infringes. So, a sculpture that "translates" a two-dimensional image to three dimensions, or vice versa, or the novelization of a film (or creating a film from a novel) would be a derivative and, if unlicensed, would infringe the copyright in the original if the two works were otherwise substantially similar.
This point appears to be what is at issue in HLE's claim against the maker of the clock mentioned in the linked article, which has a figure looking very much like Harold Lloyd hanging from one of the clock's hands. Although the clock is three-dimensional and the image from the movie is two-dimensional, that won't save it from an infringement charge if it otherwise plainly looks like the original (which, judging from the picture in the article, it seems to do).
What bothers me is the felt need on the part of the movie producers to take out licenses from HLE for other depictions of people hanging from clocks that, while in context plainly tip a hat to the Lloyd image, are not nearly close enough to the original to be an infringement.*** While the idea behind the image may have been original to Harold Lloyd--and if so it was a brilliant idea--the idea alone won't support a copyright. I can only imagine that when HLE came to the producers with its hand out, the producers figured it would be cheaper to get the license than to litigate to preserve their rights to do it for free. Considering the deep pockets of big-time movie producers, this probably made sense.
For artists, designers, shallow-pocketed filmmakers, and other businesses for whom this kind of licensing is not a daily routine, the issue is much more problematic. While the appropriateness of pure "appropriation art"--where an original work by one person is reproduced either with or without alteration by someone else as a comment on the original--has been hotly debated, it remains an esoteric rarity in everyday life. Not so with references, homages, pastiches, and other non-literal uses of pre-existing work. Many times this use has formed the basis for fair use analysis, which is a topic and a half in its own right. If a copyright owner could perform an end-run around fair use by claiming infringement of the derivative right (it's actually more complicated than that, since fair use in effect supersedes any of the owner's exclusive rights, but if broadly defined, the derivative right can throw dust in a judge's eyes when thinking about fair use), copyright law would be severely unbalanced in favor of copyright owners and against the users of information, including businesses trying to come up with clever advertising and artists making affectionate (and not so affectionate) reference to familiar cultural artifacts.
The bottom line of all this complexity is that any business that can't afford to be held up by infringement claims should lawyer up for a preliminary review before putting something out where rent-seekers can see it.
* As a point of history, under the 1909 Copyright Act, copyright term was 28 years from date of publication, which could be renewed for another 28. The 1976 Act, effective in 1978, made copyright term the life of the author plus 50 years, and subsequent extensions brought that to life plus 70 years for any new work, but with complicated transitional rules for works created before 1978. In the event, this film's copyright runs 95 years, or through 2018.
** In Back to the Future, the character dangling from the clock was played by actor Christopher Lloyd, no relation to Harold but an amusing coincidence.
*** Of course, the Ninth Circuit Court of Appeals, in California, has issued some flaky opinions stretching the definition of "derivative," but then that's what they do out there on the Left Coast.