Color infrared camera that nobody makes

[MFstooges]

I have been playing with a IR converted cameras for a while and got bored very quick. The fun stuff seems to be searching for Wood effect and even if I found that effect, more often there is not much tonality in there. Seems like the highlight is blown even that it is actually not.
Now since we know that color is only illusion, is it theoretically possible to apply an equivalent of "bayer filter" in front of the full spectrum digital sensor but instead of passing RGB ray it passes IR-A, B & C? And maybe we can use the same RGB algorithm to translate the invisible ray in the fake visible color.
If this can be done it must be very interesting to see.

 

[skylight1b]

Kolari Vision makes an "IR Chrome" filter that is used with full spectrum cameras to get that classic Aerochrome look straight out of camera. It's an expensive filter, but it seems to be the easiest solution out there. Worth a look!

 

[reddesert]

I wouldn't say that color is an illusion, rather that it is a perception. The light spectrum is a real thing, our visual system creates a perception of it using an imperfect system, film and digital cameras create a rendering of the spectrum also using an imperfect system.

Color infrared film like Aerochrome creates a false-color image where the layers are each sensitive to a light wavelength shifted redder from the dye color they create. In normal color film, the layers that are sensitive to blue/green/red light make blue/green/red dyes respectively. Normal digital cameras use the B/G/R Bayer filter to do roughly the same thing.

In color IR film, the layers sensitive to green/red/IR light make blue/green/red dyes, so you get a false color image. (Using a yellow filter to block blue light, because some of the layers are likely also sensitive to blue light.) In theory a manufacturer could 1. not use an IR-blocking filter, and 2. make a Bayer-like filter with green/red/near-IR cells, and post-process the images to make false-color IR. In practice, there's probably not a market for it and making a Bayer-like filter is probably beyond the reach of any hobbyist. I work with digital detectors for astronomy, and we use the red sensitivity of CCDs all the time, but we don't use Bayer filters, we use single-color filters, like making color separations. Amateur astrophotographers also do that.

But also in practice, you could take a full spectrum IR-converted camera (step 1 above, remove IR blocking), where now your pixels are roughly sensitive to (blue+IR, green+IR, red+IR), and try to make a filter or post-processing algorithm that would modify the in-camera color conversion to make it look sort of like false-color IR.

Kolari sells the IRchrome filter mentioned above, which is actually blue in appearance. I don't know how it works, although it seems that one main effect is to make green foliage red, and I might guess that perhaps the blue filter decreases the brightness of the green+IR channel so the red+IR channel is enhanced. Another thing that people do is swap the channel values in post-processing: https://kolarivision.com/post-infrared-photo-editing/processing-550nm-ir-filter/