"The Medium and the Message" is a short Cthulhu Mythos story by author L. C. von Hessen. It was published in the Matthew Carpenter-edited thematic anthology Pickman's Gallery by Ulthar Press in 2018.
Synopsis[]
The story is told in the form of an arts Masters degree thesis by one H. Lee Upton, a distant descendant of Richard Upton Pickman. It charts the discovery and history of a previously-unknown Pickman work uncovered in a subterranean structure beneath the streets of Boston. Many of those who studied the painting, dubbed Untitled (Red Canvas), went insane, often fatally, and predictably this begins to happen to Upton. Later discovering a film reel created by Pickman, Upton projects the images onto Untitled (Red Canvas) and his sanity decreases further, even as the events depicted on the film begin to change.
Interspersed throughout the story is an expanded history of Pickman, including his relationship with one Helen Martense, a woman who seemingly acted as a muse for his more supernatural works.