False Color Infrared Imaging
Digital Infrared photography can be used to produce monochrome or color images. Color images will always be false color. There is no such thing as "red IR" or "green IR" or "blue IR".
However there are ways of manipulating the limited color information in digital IR photos to produce beautiful surreal images. Typically, an image produced with an R72 filter, which allows a small amount of visible red light to pass through, will be manipulated by either shifting the white balance or swapping the red and blue channels.
I decided to try a very different approach to false color infrared photography. By taking three photographs of exactly the same scene: one with no filter; one with an R72 filter (720 nm cutoff); and one with an 87 filter (795 nm cutoff), and then combining just the red channels of these images, I can produce a composite false color image in which the spectrum is blue shifted. Red light becomes blue. Light on the red/IR boundary becomes green. And infrared becomes red.
Applying this Infrared - Blue Shift technique to another scene shot with my homemade 2 element f/ 2.8 lens resulted in this image.