Photobiology 102: UV Sources and Dosimetry – the Proper Use and Measurement of ‘‘Photons as a Reagent’'

The goal of these comments is 3-fold: (i) to prevent the propagation of serious experimental errors in photobiology; (ii) to improve the quality and relevance of photobiology experiments; and (iii) to save authors, reviewers and editors time. Recently several manuscripts have been received in which the title describes the use of ultraviolet radiation (UVR) to induce some effect. It is not uncommon for the description of the UVR to be limited to one or two sentences. Often the sources are described all together incorrectly. This is inexcusable for any submission, and it is an especially egregious flaw in a manuscript in which UVR is the principal reagent! The most common examples involve studies in which ''sunlamps'' are employed. These lamps are often described as a source of UVB. Some authors give a peak wavelength, e.g., 300 or 313 nm or some variation of these. Some provide the percent of UVB and UVA (almost always omitting any mention of UVC). This is at a minimum inaccurate and probably just plain wrong. The most common sunlamps are broad spectrum sources that emit radiation starting in the UVC near 270 nm and ending in the UVA near 360 nm (see Figure 1). The percentages of wavelengths in the UVA, UVB, and UVC regions are 43%, 54%, and 3%, respectively (Brown et al. submitted).