As discussed earlier, copyright gives its owner the exclusive right, for example, to reproduce protected subject matter (such things as ideas and facts being excluded). Sometimes a question arises as to whether a second, similar work was copied or independently created. If the person creating a second work had access to the original work and the works are virtually identical, copying is likely to be presumed even if the chance of access is remote.

When an artist sells copyright in a work, however, access is obviously not an issue if the same artist later executes a similar work. To avoid problems, it is important that the artist and purchaser of the copyright reach clear agreement about such matters. It is important that artists understand that a work does not have to be identical to infringe copyright in an earlier one. The legal test of infringement is “substantial similarity” — which translates (roughly) into whether an ordinary observer would recognize a work as copied in whole or in part from an earlier one.

In a similar vein, artists occasionally ask if it is OK to base a painting on, for example, a magazine photograph — even though most appreciate that turning a photograph (or some part of it) into postcards would infringe copyright. Such questions are not easy to answer. First, an artist is unlikely to be sued for using a relatively small element from another work — particularly if it used only for reference and is not copied in detail. (One who photographs a tropical scene does not get exclusive rights to all palm trees that might vaguely resemble those depicted there.)

Still, the safest course of action (particularly if you have any doubts) is: Do not copy unless you have permission or are sure it is in the public domain! Clip art is sold to be copied — use that, taking care to note any limitations that accompany it. (For example, I have a CD of clip art that can be used in printed works, but the license expressedly forbids digital distribution. Thus, I cannot use it to liven up my web pages!)