Here are the next 2 factors on fair use:
3. Amount and Substantiality of the Portion Used
Unfortunately, there is no single guide that definitively states how much of a copyrighted work could be used without copyright liability. Instead, courts look to how such excerpts were used and what their relation was to the whole work. If the excerpt in question diminishes the value of the original or embodies a substantial part of the efforts of the author, even an excerpt may constitute an infringing use. If you limit your use of copyrighted text, video, or other materials to only the portion that is necessary to accomplish your purpose or convey your message, it will increase the likelihood that a court will find your use is fair use.
4. The Effect of Your Use Upon the Potential Market for the Copyrighted Work
In examining the fourth factor, which courts tend to view as the most important factor, a court will look to see how much the market value of the copyrighted work is affected by the user in question. This factor will weigh in favor of the copyright holder if “unrestricted and widespread” use similar to the one in question would have a “substantially adverse impact” on the potential market for the work.
The analysis under this factor will also depend on the nature of the original work; the author of a popular blog or website may argue that there was an established market since some such authors have been given contracts to turn their works into books. Therefore, a finding of fair use may hinge on the nature of the circulated work; simple e-mails such as those in the Diebold case (discussed in detail below) are unlikely to have a market, while blog posts and other creative content have potential to be turned into published books or otherwise sold. In addition, the author of work not available online, or available only through a paid subscription, may argue that the use in question will hurt the potential market value of that work on the Internet.
Assessing the impact on a copyrighted work’s market value often overlaps with the third factor because the amount and importance of the portion used will often determine how much value the original loses. For instance, the publication of five lines from a 100-page epic poem will not hurt the market for the original in the same way as the publication of the entirety of a five-line poem.
This fourth factor is concerned only with economic harm caused by substitution for the original, not by criticism. That your use harms the copyright holder through negative publicity or by convincing people of your critical point of view is not part of the analysis. As the Supreme Court has stated:
[W]hen a lethal parody, like a scathing theater review, kills demand for the original, it does not produce a harm cognizable under the Copyright Act. Because “parody may quite legitimately aim at garroting the original, destroying it commercially as well as artistically,” the role of the courts is to distinguish between biting criticism [that merely] suppresses demand [and] copyright infringement, which usurps it.’”
The fact that your use creates or improves the market for the original work will favor a finding for fair use on this factor. See Nunez, 235 F.3d at 25 (finding fair use when the publication of nude photos actually stirred the controversy that created their market value and there was no evidence that the market existed beforehand).
In summary, although courts will balance all four factors when assessing fair use, the fair use defense is most likely to apply when the infringing use involves criticism, comment, news reporting, teaching, scholarship, or research.
In addition, some general rules of thumb can be helpful in analyzing fair use:
–> A use that transforms the original work in some way is more likely to be fair use;
–> A non-profit use is more likely to be considered fair use than a for-profit use;
–> A shorter excerpt is more likely to be fair use than a long one; and
–> A use that cannot act as a replacement for the original work is more likely to be fair use than one that can serve as a replacement.