THERE have been many attempts to photograph the fluoroscopic image using both cinema and still camera methods, some of which have been to some extent successful. Growing out of the desire to provide a simple, inexpensive, and yet reasonably accurate method for the surveying of large numbers of individuals for the presence of tuberculosis or other diseases of the lungs, there have been developed several schemes for photographing the fluoroscopic image of the chest. De Abreu (1, 2), of Rio de Janeiro, should be given credit for having, in 1936, first applied such a method to surveys of large numbers, employing a contax camera for photography of the fluoroscopic image on 35 mm. film, the actual space used being 24 mm. These very small films can be economically taken but must, of course, be enlarged before they can be interpreted. Using this method, de Abreu and his associates have examined several hundred thousand persons and believe it to be practical for mass examination. They report being able to examine 1,000 persons per day with one machine. Janker (3) and Ulrici (4), as well as others in Germany have used this technic quite extensively and have reported favorably upon it. Lindberg (5, 6), in this country, has adopted de Abreu's technic with some modifications of his own, and, while recognizing it as a cheap method for the examination of large numbers, in that it is more useful than the fluoroscope alone, believes that methods for the making of full size films should be improved upon rather than a definitely less accurate method. Potter (7), a collaborator in this paper in consultation with the General Electric X-ray Corporation Laboratories, after much study and experimentation arrived at the conclusion that the most desirable objective in photography of the fluoroscopic image should be the production of a small film—small enough to constitute real economy in its use, and yet large enough to be readily interpreted without enlargement, or at least no greater enlargement than that provided by a simple reading glass. Working on this basis it was found that a 4 × 5 inch film with an effective focal range slightly smaller than this would answer the requirements. Special equipment was, therefore, designed for producing such photo-roentgenographs, and it is an evaluation of this method with which this study deals. The technic of producing this film in our institution consists of the following factors: A modern x-ray installation with rotating anode tube capable of handling 400 ma. of current at from 60 to 80 kv., an impulse timer, and a tube-screen distance of 50 in. (or 125 cm.), thus producing as little distortion as possible. The time necessary for exposure depends on the thickness of the chest and varies from one-twentieth to four-twentieths of a second. The fluorescent screen used is nearly seven times as fast as the usual Patterson screen.