Let's look at these factors a bit more, one by one:

Purpose and Character of the Use

In considering this factor, judges (courts) typically look to the purpose for which the user intends to use the work.  If the purpose is for educational purposes or research purposes, that would weigh in favor of fair use.  If the purpose, on the other hand, is to make a profit or for commercial gain, that would weigh against fair use.

Importantly, courts also consider whether the use is a transformative one.  A transformative use is one that alters the original work "with new expression, meaning or message . . .."  Campbell v. Acuff-Rose Music, 510 U.S. 569, 579 (1994).  Interestingly, since this interpretation of factor one was first introduced by the Supreme Court in 1994, courts have expanded its application to all of the other factors.  In other words, the more transformative a work is, the less the "negative" weight of the other factors would impact the analysis. 

For instance, in the Google Books decision (see Author's Guild v. Google, Inc., 804 F.3d 202 (2015)), even though Google Books is a commercial enterprise (negative weight under factor 1), and was copying entire books (negative weight under factor 3), the fact that the "snippet" view used by Google Books was transformative made the use a fair one in the opinion of the Second Circuit Court of Appeals (note that this case was never decided at the Supreme Court level).

Nature of the Copyrighted Work

The nature of the work refers to whether the work was published (more likely to be considered a fair use) or unpublished (less likely to be considered a fair use) as well as whether the work is factual/historical in nature (more likely to be a fair use) or highly creative (less likely to be a fair use).

Amount and Substantiality of the Portion Used

This factor considers how much of the protected work was taken.  Did you make a copy of just a paragraph?  Or did you copy an entire book?  It is also important to consider the quality of the work taken, not just the quantity.  For instance, courts take into account whether the "heart" of the work was taken, not just whether a substantial portion was reproduced.

Effect of the Use Upon the Potential Market for or Value of the Copyrighted Work

In this factor courts generally consider whether the use of the copyright protected work would replace the market for the original work.  For instance, if I copied and pasted an entire book of the Harry Potter series online then individuals wishing to read the book would no longer have to purchase the book and the author of the book would be harmed.  Thus, that would not be considered a fair use.  However, if I wrote an essay, a piece of fan fiction using the names and likeness of the characters from Harry Potter but with a new plot, perhaps it would not easily replace the original and would not supplant the marketplace of the Harry Potter book sales (however, remember that derivative works are also under the control of the author, so if the new piece of fan fiction were not transformative enough, it likely would not be considered a fair use overall--remember that all factors, not just one, need to be weighed when considering fair use).

Documenting Your Good Faith Attempt to Determine Fair Use

There are many useful online tools to utilize in order to determine whether a particular use is a fair use.  However, remember, no-one can determine fair use in a specific case except for a judge!  So, there is always some amount of risk involved when claiming that something is a fair use.

Regardless, it is a good idea to document, for your own records, your good faith attempt in determining whether a particular use of copyrighted material is/is not a fair use.

Frequently, researchers wish to utilize charts or graphs of factual data created by another author in their own research or publication. As noted on the Copyright Basics page, copyright protection does not extend to protect facts. The question, then, is whether copyright protection extends to the "arrangement" of facts as presented in charts and graphs. Generally speaking, if there is only one real way to present the data, whether it be a pie chart or a graph, the factual representation is not protected by copyright.

Whereas, if there is some amount of creative expression involved in the arrangement of the factual information (for instance a painting depicting factual data gathered from daily temperature readings), then the arrangement of the data would be protected as a creative expression.

For more information about one interpretation of whether the display of factual data is protected by copyright, see Copyrightability of Tables, Charts, and Graphs [pdf] by Bobby Glushko.

Innesw, Chart SVG Example 5 -Simple Pie Chart.svg, commons.wikimedia.org, CC-BY-SA 3.0.

Regardless, it is a good idea to document, for your own records, your good faith attempt in determining whether a particular use of copyrighted material is/is not a fair use.

Here are a few websites that can guide you through that process and provide you with documentation of your good faith efforts:​

Additionally, and as always, you may contact the Copyright Librarian, Sara Benson at srbenson@illinois.edu for additional assistance.