Despite countless articles and FAQs about Fair Use, the actual application of the law is based on the individual circumstances. In other words, Fair Use is truly a judgment call.
I think the law was designed to be flexible and that is a good thing. It has been around as a doctrine for a long time until it was finally set as law in the 1976 US Copyright Act.
The four Fair Use factors used to measure the law are very broad. Take "purpose and character of use" for example. Say you transform an image by a recognizable photographer and add something new to it so that your rendition gives it a very different purpose. Is that considered permissible under Fair Use?
Possibly. What about a photo published in Time magazine in an editorial usage that another person transforms by adding or removing elements, perhaps turning it into an animated gif, and then posts it on their social media page as a political meme. Can the copyright holder win an infringement suit in such an instance?
To figure that out, all of the Fair Use factors come into play. How much of the original image has been used relative to the transformed image? There is no measuring stick in the law, but if you only retain a small bit of the original in your new work, then it's more likely to be considered Fair Use compliant.
Does the use of your new work compete with the value of the original? Most parody artists understand this and select highly recognizable content so they can claim their work is only being seen by a small audience and is not in competition with the original. But what if the new work "goes viral" and surpasses all their expectations?
Even in that instance, the copyright holder would need to prove that the rendition art actually diminished their potential market. Not so easy.
Say you use an image you found online that has a Creative Commons license to illustrate an article on your own website. You think as long as you provide attribution as the copyright holder requested, you are in the clear. But courts have ruled that this is not Fair Use if the photograph was used to generate advertising revenue based on page views. In other words, the use is commercial and not transformative. Even trying to argue that there was no potential market for the Creative Commons image because it was available for free and the copyright holder didn't make any money licensing or selling prints of the image, the weight of that single factor towards a Fair Use claim may not be enough to outweigh the others.
Copyright infringements happen every second and some enterprising companies are cashing in by providing reverse image matching tools that help identify potential violations. So if you are using images found online and repurposing them without permission, it's a good idea to know if Fair Use really applies. As these tools become more sophisticated, it might not be worth the hassle and expense to take a chance.
The US Copyright Office has a searchable Fair Use Index that tracks court decisions in Fair Use cases.
A note to creators: Copyright registration is not required in order to protect your work because copyright protection is automatically granted the moment you create works that qualify. But before you can sue someone in US federal court for infringing your copyright, you must file an application for registration. And there are time limits surrounding this.
Do you think Fair Use law should be expanded, removed altogether, or should it remain as unclear as it is now? Do you have any examples of Fair Use that you aren't entirely sure about or any case outcomes you disagree with?
This is not legal advice but a discussion of Fair Use law. (@orangejulius: Brian, are you still available to weigh in?)