The 720nm standard wavelength of light (being on the edge of the colour spectrum of light visible to the human eye) captures some weak colour in the red and blue colour channels which you can use for faux colour infrared images. The standard practice for faux colour infrared photography has always been to swap the red and blue colours using the "channel mixer" to give your image a blue sky.
|Birkenhead Park Boathouse - 720nm infrared channel swapped|
The 590nm super colour wavelength of light is closer to the colour spectrum giving you a mix of the colour spectrum and infrared light. As an infrared photographer this gives you more creative options for coloured infrared as you now have some colour in the Red, Yellow, Blue and Cyan channels. You can swap colour channels as before and adjust the hue and saturation of each colour individually to produce a psychedelic world of faux colour.
|Bodnant Hall, Wales - 590nm infrared channel swapped|
|Bodnant Gardens Terrace - 590nm super colour infrared|
As you can see from the images above taken with a Sony A6000 720nm standard infrared camera and a Sony A6000 590nm super colour infrared, the latter captures more colour to play with in post production. Can you go further? Yes you can.
Last year I stumbled on a Youtube tutorial hosted by the Master of infrared photography Mark Hilliard in the United States on creating faux colour infrared images using Nik Viveza 2. The technique allows you to use the software's U-point technology to selectively colour foliage. Place a control point on the foliage of a tree and you can change the hue, saturation, warmth, brightness to colour the foliage in pastel shades. It works with all wavelengths of infrared except 830nm pure infrared which has no colour recorded in the image to be used by Viveza.
|Birkenhead Park Boathouse - 720nm infrared processed using Nik Vivessa2|
|Biddulph Grange - 590nm infrared processed using Nik Vivessa 2|