Black light

The Wood lamp is a special lamp, the long-wave primarily ultraviolet radiation ( black light / UV -A) and emits visible light in the blue spectrum, only a small extent. The Wood's lamp was named after the American physicist Robert Williams Wood, who developed it in 1903. It is used in the medical field of dermatology early diagnosis of various skin diseases. In legal medicine may be used for example for the detection of blood and semen.

Use in dermatology

With the use of Wood's lamp in the dermatology fluorescent foci and pigment changes can be appraised on the skin. Certain dermatophytes it is in a darkened room to a yellow-green fluorescence caused by tryptophan metabolites of these fungi. This analysis method was introduced in 1925 by Margarot and Deveze in the mycological diagnostics. Also, bacterial pathogens such as Pseudomonas and Propionibacterium acnes lead to fluorescence.

Use in forensic medicine

In the forensics such traces can be visualized under the light of Wood's lamp by the fluorescence of blood and semen. However, this detection method has only limited reliability due to some significant limitations and shortcomings.