^ abHarold M. Merklinger (1996). "Scheimpflug’s Patent"(PDF). Scheimpflug himself disclaimed inventing the rule that now bears his name. The Scheimpflug Principle (or rule or condition) provides guidance on how a camera lens and/or back should be tilted when focusing upon a plane that is not parallel to the film. This short article is intended to provide a little historical background and technical information about Scheimpflug and his patent. If Scheimpflug did not invent this rule, who did? Scheimpflug cites only one reference, and that is to the British Patent of Monsieur Jules Carpentier of Paris. In 1901 Carpentier had patented an enlarger for correcting converging verticals. Carpentier made this claim: "I have investigated the law which governs the correlation between the inclination of the plane of the negative and that of the sensitized surface to that of the optical axis of the lens...and I find that the relationship is this:—If the two planes are sufficiently prolonged they must intersect in the plane perpendicular to the said axis and passing through the optical center of the lens.