Copyright protection requires that a work have at least a minimum amount of human creativity, but the laws are vague as to what this minimum is.
Legally, US copyright protection is provided for information (typically preserved in a non-transitory medium) that has at least a small element of a human author’s own creativity. Courts have held that mere facts and ideas alone can’t be copyrighted. The amount of creativity can be very small, but it isn’t zero. For example, using human judgment to select and compile facts according to personal criteria often qualifies, and an author’s annotations of facts may also qualify, but routine alphabetical sorting is not enough (Feist Publications v. Rural Telephone, 499 US 340, 1991) .
From an engineering or mathematical perspective, these rules may look vague. This is in part because these concepts date back hundreds of years, back to the early days of printing presses, and have evolved slowly over time through various laws and court decisions. However copyrights are big business, and copyright law enforcement tends to be efficient and harsh. So like them or not, the rules are important.
One area where the rules are fuzzy is short works, such as short sections of text or individual photographic images. What is the minimum work (creative information) that might get copyright protection? The rules are not uniform throughout the world, and here we are discussing US laws.
Short text: Very short text fragments are often considered too trivial (de minimis) for copyright protection, but the court will consider originality here, and more originality gets better protection. Although there is no minimum word-count cut off, text fragments of 11 words or less at the “news article” level of originality are often considered non-infringing.
Individual photographs: Again the law requires a small amount of human creativity for copyright protection. The US copyright office will not register works produced by non-humans, and lower court cases are consistent with this decision. Additionally, exact copies of public domain work (Bridgeman Art Library v. Corel Corp.) are also exempt from copyright. Otherwise, the courts often ignore the creativity requirement. This raises some interesting questions for future cases. However, unless the law changes, assume that copyright applies to nearly all human-produced photographs, no matter how repetitious, trivial or otherwise non-creative.
There are other copyright exceptions. Federal Government work is often not copyrightable. Further, under “fair use”, there can be additional exceptions where it is OK to reproduce another’s copyrighted work. Fair use rules are complex and will be the topic of another discussion.