This study tracks changes in behavior and attitude among visual arts professionals after the development of a code of best practices in the copyright doctrine of fair use. A survey of 2,400 professionals fielded only months after its publication demonstrated broad awareness of the code, informing practice and inspiring efforts to spread awareness. The greatest degree of awareness and change was among editors, several of whose publications altered their copyright policies. Professional and social networks were critical to spreading awareness. Despite a continuing lack of confidence in interpreting the law among individual professionals, the existence of a code contributed to significant change in norms and practices via institutional adoption. This study demonstrates that codes of best practices can affect field behavior, but that change depends on publicity, formal education, continuing support for early adopters, and institutional policy changes.