These filters offer both amateur and professional photographers HOYAs famous quality at reasonable prices. They have coatings applied to both surfaces to suppress reflection and increase light transmission. Used for photography with infrared films. 0nm. Oft en used in crime detection, medical photography, detection of distribution of vegetation, etc. In ordinary photography with infrared film or infrared color film, the Yellow (K2), Orange (G), Red (25A) and other filters can also be used to change the contrast or color effect.