Under Fair Use, permission to use a work is not required under certain conditions. This allows free use that contributes to the creation of new works and is not likely to affect sales of the material.
Examples include:
criticism and commentaries
news reporting
teaching
research
The Four Determining Factors
Purpose and character of the use
Is the use for commercial or nonprofit education purposes.
Has the material been transformed by adding new expression or meaning?
Was value added to the original by creating new information, ideas, or understanding?
Nature of the copyrighted work
Is the information factual?
Has the information been published?
Amount and substantial of the portion used
How much of the whole work is being used?
Is the part of the work being used especially important to the work?
