Ultraviolet photography sensor will pick up reflected infrared radiation as well as ultraviolet, which may obscure the details that would be resolved by ultraviolet alone. Most types of glass will allow longwave UV to pass, but absorb all the other UV wavelengths, usually from about 350 nm and below. For UV photography it is necessary to use specially developed lenses having elements made from fused quartz or quartz and fluorite. Lenses based purely on quartz show a distinct focus shift between visible and UV light, whereas the fluorite/quartz lenses can be fully corrected between visible and ultraviolet light without focus shift. Examples
Ultraviolet light therapy that tanning beds that primarily emit UVA cannot be effective for the treatment of psoriasis. Other limitations to the use of tanning beds for the treatment of skin conditions include the imprecise output of the lamps and beds, imprecise spectral targeting of commercial tanning beds, the fact that the patient or non-medical staff run the machines, and other acute or long-term side effects. Ultraviolet light therapy Ultraviolet light therapy or ultraviolet phototherapy is a form of treatment for certain skin disorders including atopic skin disorder and vitiligo when used with psoralen to form the PUVA treatment. It consists of irradiation