The spectral erythemic reaction of the untanned human skin to ultra-violet radiation

Abstract

The spectral erythemic reaction of three persons exposed to equal amounts of homogeneous ultraviolet radiation, of various wave lengths, is described. The source of radiation was a standard vertical quartz mercury vapor lamp which has a series of intense conveniently spaced emission lines, extending from 248 to 365 m/i. These emission lines were separated by passage through the spectrometer exit slit, the jaws of which were dusted with anthracene, .which, by fluorescence, indicated the accuracy of the isolation of the line under investigation. The erythemal reaction and the radiometric measurements were made on the spectral line directly back of the exit slit. In the region of 250 mn the spectral erythemic reaction was supplemented by exposures to the heterogeneous radiation from a mercury vapor lamp having a high selective emission in the resonance line at 253.7 m/i. Data are given on the reciprocity of intensity and time of exposure, and also on the relative spectral erythemic reaction in the range of wave lengths extending from 245 to 315 mju.

Tests of a balanced thermocouple and filter radiometer as a standard ultra-violet dosage intensity meter

“…As mentioned in a previous paper (5) the erythema produced by radiation of wave lengths less than about 270 m/z is superficial and becomes visible within about an hour after exposure. If the exposure is mild, the erythema begins to disappear in the course of 5 hours.…”

“…The various details in determining the spectral erythemic response of the untanned human skin are described in a preceding paper (5).…”

“…To derive the erythemogenic efficiency of a heterogeneous source of ultra-violet radiation the ordinates of the observed spectral energy curve are multiplied by the respective ordinates of the spectral erythemic response curve (5) . The resulting rubescence curve (see p. 735 and 747 of reference (3)) is analogous, in principle, to the luminosity curve of a source of light (10).…”

Ultraviolet transmission changes in glass as a function of the wave length of the radiation stimulus

“…For investigating the photochemical action of homogeneous radiation, the above-mentioned vertical quartz mercury arc lamp was operated at a constant potential (70 volts). The single wave lengths were isolated by means of a high-powered quartz spectropyrheliometer, as used in previous investigations (14). The intensities of the lines at the exit slit were evaluated in absolute units.…”

“…The completion of an investigation of the physiological (erythemal) action of homogeneous ultraviolet radiation (14) released apparatus for a similar study of the photochemical action of these wave lengths upon the ultraviolet transmission of glass. The results of this study, using the experimental procedure described under caption II, are…”