|American slide for Lady with a Past (1932) and Australian slide for Man in the Trunk (1942)|
|Double pane construction on left: The Sheik (1921). Single pane construction example on right: On Guard (1927). Both slides produced by Excelsior Illustrating Co.|
Despite the presumed advantages of the cardboard frame design, double-pane construction was not abandoned and continued to be used into the 1980s. Therefore, while you can be certain that a slide framed with cardboard was manufactured after the April 1923 patent application, the inverse does not necessarily hold true.