What defined many scientific photographs as a genre was not merely their subject matter (e.g., lightning, clouds, microscopic objects, planets) or even their production at the threshold of human vision. Instead, what made them scientific photographs in the eyes of officials was often based on such considerations as how they were made and by whom and where they were exhibited, as is still the case today.

Jennifer Tucker, Nature Exposed, Johns Hopkins University Press, 2006, p. 7