title: Photographic subtraction. II. Technical aspects and method.
abstract: Technical aspects of photographic subtraction of original films in black and white and blue and white (Medichrome) under standard development conditions available in any roentgen unit are described. The adjustment necessary to control the gamma-value of the masking film takes advantage of the capacity of some graphic films to respond with different gamma-values on variation of the color of the exposure light.
mesh_terms: D004655:Emulsions; D008027:Light; D010781:Photography; D013382:Subtraction Technique / Q000379:methods*
chemical_list: D004655:Emulsions