Although Gertie is popularly thought to be the earliest animated film, McCay had earlier made Little Nemo (1911) and How a Mosquito Operates (1912). The American J. Stuart Blackton and the French Émile Cohl had experimented with animation even earlier; Gertie being a character with an appealing personality distinguished McCay's film from these earlier "trick films". Gertie was the first film to use animation techniques such as keyframes, registration marks, tracing paper, the Mutoscope action viewer, and animation loops.