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I've been interested in infrared and near-infrared camouflage (called multispectral camouflage) for a couple of days now, and I've found a video or two of certain companies that have created fabrics that both reject outside thermal and near-infrared radiation, and allow for scattering of infrared and near-infrared radiation originating from the body as body heat.

It's been three days and I've been searching for the materials science behind the camouflages, but I can't find anything relevant.

So, what materials/substances do you think they are using for this type of camouflage and why?

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  • $\begingroup$ What do you mean by "reject" and "scattering"? Is the aim for a body to appear black when illuminated by an IR lamp? And you can only scatter outside light. Thermal emission always occurs in all directions anyway. $\endgroup$
    – Karl
    Apr 7, 2020 at 14:11
  • $\begingroup$ The aim is both to take incoming thermal (IR) radiation, and thermal energy from body heat, and when the material radiates the IR energy it sends it off into arbitrary directions, not just toward the observer, lowering absorbed heat by the observer. In this sense the external heat (for instance from an IR lamp) is not very reflected by the material; it should appear like normal background when illuminated, but also take internal body heat and "diffuse" it in all different directions, again, giving out a heat signature that is similar or equal to the background. $\endgroup$
    – August H
    Apr 7, 2020 at 15:13
  • $\begingroup$ You seem to be missing the point. Except polished metal, hardly any material reflects (like a mirror) IR. And any warm body, including a piece of camouflage, radiates thermal IR into all directions. You can add an insulation layer on the inside to keep your body heat, but I think that´s not the idea here. $\endgroup$
    – Karl
    Apr 7, 2020 at 15:57
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    $\begingroup$ The wiki article suggests that Peltier devices are used to spatially modulate the thermal output across an object to break up an infrared image. Is that kind of what you mean? $\endgroup$
    – Jon Custer
    Apr 7, 2020 at 16:00
  • $\begingroup$ What would make sense is a material that absorbs NIR (making it look black in an IR searchlight), and does not absorb FIR, because a low absorbance generally means a low emittance at the same wavelenght. Could that be it? $\endgroup$
    – Karl
    Apr 7, 2020 at 16:02

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