Abstract: A method for inspecting the material distribution of a sequence of stretch blow molded containers or other articles in a continuous production process, by providing injection molded parisons, each parison having at least one indicator, typically two or more indicators, for detecting material distribution at a predetermined position along the axial extent of the parison. Each of the parisons is subjected to a heating stage in the continuous production process, generally by exposure to infrared heating. Each heated parison is then subjected to a blow molding process, which can be a stretch blow molding process, so that each material distribution indicator is transformed to a corresponding position along the axial extent of the blow molded article. A detector is positioned to detect the location of each indicator on each blow molded article from a given mold in the production process.