Infra-red light is a frequency of light that is not visible to our eyes yet exists all around us. We can only see the colors of the spectrum red through violet but digital cameras are sensitive to infra-red light as well. Since it cannot be seen by human eyes a filter is put on all digital sensors to block it. This filter can be removed in a permanent alteration to the camera. When this is done the camera takes photographs in a much different way. Skies become darker blue, the chlorophyl in leaves becomes white and other unexpected results appear.