This UV filter blocks the invisible UV component of light from the sky, which can cause blurriness and to which many color films react with a bluish tint. These filters should be referred to as UV-blocking filters, as there are also filters for technical applications that allow UV radiation to pass through while blocking all other wavelengths. Nevertheless, the term "UV filter" has become established among photographers. UV filters are ideal for photography at high altitudes (in the mountains), by the sea, and in regions with very clean air. The images gain brilliance, and distracting blue tones are avoided. Since the glass is colorless, color reproduction is not altered, aside from the elimination of the unwanted blue tint, and no increase in exposure is required. This makes a UV filter very suitable as protection for the front glass of the lens against dust, flying sand, sea spray, and similar elements, and it can remain on the lens at all times. It is recommended for both analog color and black-and-white photography, as well as for digital photography.