The B+W 093 Infrared Filter blocks the entire visible spectrum and so to our eyes looks completely opaque. Unlike the 092 filter, it makes pure infrared photography possible by eliminating the visible spectrum. Its transmission only begins to exceed 1% at 800 nm, rising to 88% at 900 nm, and remains that high far beyond the upper limit of sensitization covered by infrared films. This filter results in dramatic loss of effective ISO, but in the scientific field, materials research, and forensics, the limitation to a strictly infrared range is often important. Effectiveness and filter factor are largely film and light dependent. For digital use, built in UV/IR filtration varies from camera to camera. Individual testing is recommended for both formats.