Simultaneous Infra-red Roentgen Photography

Abstract

INFRA-RED photographs in so-called total darkness have been obtained with various filters, such as the Wratten No. 87 infra-red filter. Infra-red photographs in so-called total darkness, of various sources of heat have also been obtained. It has also been shown that by directing a source of heat toward an object, excellent infra-red photographs can be made. Whenever a source of heat is used in this way the exposure time is considerably prolonged. For example, in the latter instance, with the aid of two hot flatirons, the infra-red photograph was obtained after an exposure time of one hour. In the experiments under consideration, however, the exposure time for the infra-red photographs which are taken in total darkness range from 1 to 10 seconds. Material and Methods.—The apparatus employed in these experiments is shown in tight box with the emulsion side of the plate directed upward. A Cecropia moth is placed upon the photographic plate in contact with the emulsion. The sliding filter, opaque to the visible spectrum, is closed over the window in the box, thus placing the infra-red plate and the moth lying on the plate in total darkness. This so-called filter, which closes over the window in the box, was made from a plate holder slide marked with four dots, which is safe to use in the plate holder with the ordinary photographic emulsions, but which, when used with the infra-red plate and exposed to light, will cause fogging of the plate. Daylight or the light from an incandescent tungsten bulb is then directed through the filter in the window of the box for eight seconds. The loading of the box and development of the plate are done in total darkness. Infra-red materials and methods are discussed by the author in detail in three previous publications (Massopust 1, 2, and 3). Observations.—Upon development the resulting image shows all of the detail of that side of the moth which is in contact with the emulsion of the plate and directed away from the source of radiation passing through the filter (Fig. 2). It is to be noted that there is also evidence of some penetration as seen in the regions where the wings of the moth overlap. Figure 3 is a roentgenogram of the moth placed in the same position on the plate as that shown in Figure 2. Due to lack of density in the wings, no image of the wings is obtained with the ordinary roentgen apparatus. Thus, only the image of the body of the moth is recorded on the plate. Figure 4 is obtained by placing the moth in the same position on the plate as in Figures 2 and 3. Light from an incandescent tungsten bulb, and the roentgen ray is directed through the filter simultaneously. The result is a simultaneous infra-red roentgen photograph. Figures 2, 3, and 4 are contact prints made from the original plates. In Figure 5 the plate used in Figure 4 was rephotographed and then a print made.