Fair dealing is a doctrine that allows for copying of a reasonable amount of a copyrighted material if it is for specifically allowed purposes. The main purposes for which material may be copied include using it for criticism, reporting the news, private study, or research and legal advice. The doctrine will likely not apply to cases where the copied material is the primary source of information for a publication, and that publication is sold commercially.
The biggest question often surrounding fair dealing is how much of a certain type of material may be used. The answer is not simple because it depends greatly upon the situation. For example, for criticism or review, fair dealing is often thought to be limited to 400 words in a single quote, and less than 800 words total. For other situations, copying material is limited to no more than 5% or 10% of the total work.
In addition to printed materials, fair dealing may also come into play with motion pictures. In such cases, the concept of copyright exceptions only applies in cases where a person is reviewing or providing criticism of a film. Typically, to avoid any possible problems, the clips used should not last any more than a few seconds.
Despite these guidelines, determining when copying material crosses the line from fair dealing to plagiarism is difficult. Rules are vague in order to provide the courts with enough leeway to make their own decisions. At the very least, the amount of original material should be greater than the amount of copied material.
When fair dealing is used to quote material, an acknowledgment of the original author must be provided in every single case. Without sourcing the material to its original creator, it may be considered a violation, even if fair dealing is used as a defense. Without proper citation, it may seem as though the individual quoting the material was the original creator. Even if the context made it clear that the author of the quoted material is different, proper citation is essential to assuring credibility.
Some non-original material may be quoted in its entirety or even sold commercially, and is not subject to fair dealing rules. This is material that is so old the copyright has expired. The exact number of years until a copyright expires depends on the country in question and what extensions, if any, have been filed. If the copyright expires, the material is said to be in the public domain, and then can be used without paying any royalties to the original owners. Crediting the original author is still standard practice, however.