title: Photographic subtraction. I. Theory of the subtraction image.
abstract: The purpose of subtraction of angiographic images is to demonstrate the vessels free of superimposed, disturbing image noise. With the aid of physical film parameters the theoretic basis for an optimum subtraction technique is presented.
mesh_terms: D000792:Angiography; D003116:Color; D005373:Film Dosimetry; D006801:Humans; D010781:Photography; D013382:Subtraction Technique / Q000379:methods