What is Color Infrared (CIR)?
Color-infrared photography film has a yellow filter over the three emulsion layers to block ultraviolet (UV) and blue wavelengths. Processing color-infrared film after exposure produces yellow, magenta, and cyan dyes. The near-infrared wavelengths and the lack of UV and blue wavelengths result in a clear, crisp color-infrared image. Green vegetation appears red; red objects appear green; green objects appear blue; and blue objects appear black. Please visit USGS for more detailed information.