Human perception is limited to the visible (VIS) spectral range that is defined by the luminous efficiency functions ranging between wavelengths of λ=380 nm and λ=780 nm. However, sensors in cameras have a sensitivity to about 1100 nm. In order to match the appearance of photographs to the human visual sensation, the near-infrared (NIR) part of the radiation incident on cameras is usually blocked by an IR cut-off filter. If this filter is removed, the incident radiation also contains the NIR, and the appearance of the resulting photographs changes. If an additional filter to block the VIS light is used (I use a 1000nm filter), the modified camera then only detects NIR radiation, which can lead to strange and beautiful effects in the appearance of photographs of well-known objects. For more information about photobiomodulation please go to nir1000.com