[Light test on human skin].

Photo-patch and other photo-skin-tests are essential for many scientific and clinical studies. There are relatively simple techniques of handling that can be carried out even in practice, but also rather complicate procedures. Testing must be strictly adjusted to the specific problem in order to avoid false results. For clinical concerns, photo-skin-testing has to be done with UVA light, because most of the pathological light reactions are induced by UVA. As the role of visible light has not been investigated yet, we are doing some experiments employing a special unit emitting the action spectrum of visible radiation only.