Under the framework of intellectual property law, to legally sell adapted products without infringing copyright, it is necessary to strictly abide by legal principles, while combining specific judicial practices and case experience. The following are some key strategies and precautions, but it should be noted: **This article does not constitute legal advice**, you need to consult a professional lawyer for specific circumstances. --- ### **1. Understanding the core principles of law** Before adapting the work, the following legal foundations need to be clarified： -**Scope of copyright protection**: Copyright protects expressions (such as specific forms of text, images, and music), but does not protect ideas, facts, or functions (such as game rules, mathematical formulas). -**Adaptation Right**: Without the authorization of the copyright party, the original work may not be “substantially adapted” (such as translating or adapting a novel into a script). -**Fair Use (Fair Use/Fair Dealing)**: Some countries allow limited use of works for criticism, commentary, satire, education and other purposes, but strict conditions (such as the US “four-element test”) must be met. --- ### **2. Potential path of legal operation** ####**(1) Reasonable use (subject to strict evaluation)** -**Transformative Use**: The adapted work needs to give the original work new meaning, information, or aesthetic value (such as satirical imitation, academic analysis). For example, the U.S. Supreme Court in Campbell v. In the Acuff-Rose Music* case, it was determined that 2 Live Crew's parody of the song "Oh, Pretty Woman" was fair use. -**Restrictions on commercial use**: Commercial use may weaken the defense of fair use, but it may still be established when the degree of conversion is high. -**Use proportion**: Avoid copying the “core creative expression” of the original work, such as quoting only fragments instead of the complete structure. ####**(2)Public Domain (Public Domain)** -Use works whose copyright has expired (such as Shakespeare's plays and Beethoven's music) for adaptation without authorization. -**Note**: Some countries (such as the European Union) have special regulations for “re-recording after copyright expires”. ####**(3)Creative Sharing Agreement (Creative Commons)** -Use works under the CC agreement (such as CC BY, CC BY-SA) that are clearly marked “adaptation and commercial use are allowed”, and comply with the terms of the agreement (such as signing the original author). ####**(4) Independent creation and ”clean room" process** -**Independent creation**: Ensure that the adapted work is not materially similar to the original work (for example, different stories are created based on the same historical events). -**Clean Room**: Adapted by a team that has not been exposed to the original work, and is only based on public domain or authorized materials to avoid “subconscious plagiarism.” ####**(5)Copyright exceptions and compulsory licenses** -Some countries allow compulsory licenses for specific purposes (such as compulsory licenses for music covers in the United States), but legal fees are required. --- ### **3. High-risk behaviors need to be avoided** -**Non-transformative adaptation**: For example, the novel is directly rewritten into a comic, but the core plot and characters are retained. -**Confusing use**: The adapted work may cause consumers to mistakenly believe that it is related to the original author (it may also violate trademark laws). -**Copy unique elements**: Even if the details are modified, if the “unique expression” of the original work (such as character design and iconic lines) is retained, it may still infringe. --- ### **4. Practical advice** 1. **Legal review**: Entrust a lawyer to conduct an “infringement risk assessment” (such as a “substantial similarity” analysis) before development. 2. **Contract authorization**: If possible, contact the copyright party directly to obtain an adaptation authorization (such as purchasing an IP derivative product license). 3. **Keep evidence**: Record the creative process (drafts, timestamps) to prove independence and transformability. 4. **Insurance and risk isolation**: Purchase intellectual property infringement insurance, or isolate risks through shell companies. --- ### **5. Typical case reference** -**"Cariou v. Prince"**: Artist Richard Prince's collages of photographic works are recognized as fair use because they are highly transformative. -**"Andy Warhol Foundation v. Goldsmith"**: The U.S. Supreme Court ruled that Warhol's adaptation of the singer's photos did not constitute fair use because it did not fully transform the core purpose of the original work. --- ###**Conclusion** There is a high degree of uncertainty in the gray area of intellectual property law, and judicial decisions may vary from country to country, judge to judge, and case details. The core of legal operation lies in： 1. **Minimize substantial similarity to the original work**； 2. **Strengthen the transformative and original nature of the adaptation**； 3. **Priority is given to obtaining authorization or using risk-free materials**. Final recommendation: When commercial interests are involved, work with professional intellectual property lawyers to formulate strategies.