Sarah Louise Lordan 

A study building out from Postmodern theorist, Douglas Crimp's presumption that Appropriation artworks fall under one of two headings: "Stylistic" or "Materialistic" Appropriation (this theory is specific to the physical act of appropriating).
Photography Imitating Art takes another step back in the production process, looking at categorising Appropriation artworks based on how they came into existence: via "Concept" or "Research" (this theory is specific to the metaphysical thought-process that an artist goes through when creating Appropriative art). Concept-Based Appropriation suggests that the act of appropriating originated from an idea that the artist had in a moment of divine inspiration. Research-Based Appropriation suggests that the act of appropriating originated from the somewhat intentional gathering of information, which informed the artist's understanding of a given subject. By appropriating the information, the artist's intentions are reinforced or countered by pre-existing connotations to the subject matter.
Research and Concept can be considered primary characteristics of an Appropriation artwork, outlining an artist’s forethought and rationale; as without either of these aspects, an artwork could not be conceived. Consequently, Stylistic and Materialistic Appropriation can be considered secondary characteristics that determine the process of expression, describing the techniques by which the artist has appropriated a previous work.