NIR, SWIR, FLIR. Those are acronyms for a few of the many different detection methods with which tactical operators must contend when they need to be concealed or simply to blend into their surrounding environment. NIR is one of the oldest of these detection methods. In this post, we explain what it means for an article of tactical clothing to be NIR-compliant, how it becomes NIR-compliant, and what relationship this compliance bears to the camouflage pattern printed onto that garment.
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Our bet is you’ve probably come across the topic of NIR compliance and faced some issues with it. On paper, this compliance is a must; ergo a lot of people ask us questions like, “Is MultiCam NIR?” Some of the questions make sense, but others don’t.
This is why it’s important to address this topic and debunk some common misconceptions about it. Let's start off easy.
Infrared vision has been around for million of years. Frogs, snakes, and fish are among the many animals that have IR vision. But not mammals. IR vision is absent from mammals (including humans) because mammalian eyes lack the proper receptors for it.
But humans can compensate for that shortcoming by improving our information processing. You see (no pun intended), the NIR spectrum offers us a lot of intel we would normally miss out on, especially as we are really dependent on light in the visible spectrum in order to be able to glimpse what’s going on around us at night.
This isn’t entirely bad because, even though it’s hard to see at night, the lack of visible light after sundown enables us to remain unseen while giving us the opportunity to tap into the NIR spectrum to observe and gather data.
And that’s why there are night-vision devices. The technology underlying them is mainly tied to warfare, as the ability to see in the dark was extremely useful for the military.
The first successful night-vision devices were developed in 1939 by Germany for use aboard Panther tanks. These initial devices are labeled Generation 0.
Image source Wikipedia.com
The next notable milestone in night-vision development was the war in Vietnam, which yielded Generation 1 technology. Both Generation 0 and Generation 1 night-vision devices worked by amplifying ambient visible light. Further research enabled the generations that followed to utilize not only ambient starlight and moonlight but also other spectrums including NIR.
You probably know this one, but let’s mention it anyway. NIR stands for near-infrared and it’s used for denoting light that’s just outside of the visible range—basically that measured in the wavelength band between 780 nm and 2,500 nm.
Image source: Wikipedia.com
In addition to the benefits it offers the military, the NIR spectral range is also useful in science. Researchers use NIR to gather insights concerning the chemical structure of materials. Specifically, it’s possible to test the various chemical bonds of different materials by looking at their NIR-spectrum absorbency.
As mentioned earlier, NIR cannot be detected by the naked human eye and that makes it useful in the tactical space. Something else NIR does: when used in light-form imaging, it preserves more detail at longer ranges. Moreover, it’s not disrupted as easily by fog and haze as are shorter IR waves. Further, it results in images that are (for humans) clearer and more easily understood.
The downside of imaging in NIR is a “lack of colour.” NIR is outside our visible colour range and this prevents us from seeing what we perceive as red, green, or blue.
Another downside is the requirement that NIR light originate from a source in order to be bounced off objects.
How NIR affects clothing
If you’re concealed and the opposing team knows you’re out there somewhere, they’re going to be trying very hard to spot you. That basic fact of tactical life gives rise to the need for you to be equipped with detection-avoidance capability.
The best technology in support of detection-avoidance capability is the clothing you wear, since it covers most of your body. In addition to providing basic protection against the environment (rain, sun, wind, and so forth), your clothes also provide a platform upon which a camouflage pattern can be overlaid. In other words, you are already wearing clothes; in order for them to conceal you, they just need to be adapted.
Image source: Hyperstealth.com
The goal of that adaptation is to configure it in such a way that it disrupts the outline of your body from the vantage point of someone looking in your general direction from a distance. That’s the goal, and it’s met with patterns like MultiCam and Flecktarn.
But, with NIR, there’s a twist. Think, if you will, of matching a uniform to a forest environment. In that environment are bark, leaves, and soil—all of them different in hue and shade. So the uniform’s camouflage pattern needs tans, browns, and greens. A hard job indeed. But what if the only colour present in the forest were green?
Imagine it. Green bark, green leaves, green soil. That would certainly make coming up with an effective camouflage pattern a lot easier.
Well, that’s actually the concept behind NIR masking. It focuses on one wavelength (in our example, the colour green) and tries to match the environment.
We choose green as the example because that’s what you see when you look through the eyepiece of a night-vision device. The images are green. Ever wonder why that is? It’s because green is the colour that human eyes tolerate best when having to look through a night-vision device for a lengthy period.
A good thing about NIR is that it does not translate “colour.” Instead, it presents light in varying degrees of intensity bouncing off objects such as trees, foliage, and soil. Matching this reflected NIR light with your environment is what we call NIR compliance.
A common misconception is that NIR compliance is something inherent to colours and camouflage patterns. The truth is that NIR compliance is a property of the fabric and of the dyes used on it.
Does this mean that within a single pattern—MultiCam, for instance—there can be multiple NIR properties? The answer is yes. It all depends on the type of dye or coating used.
Image source: Hyperstealth.com
The image above illustrates best what we are trying to convey. Here, you see a regular MARPAT pattern fabric, but half of it is coated with a highly NIR-absorbent coating. The difference is clear. When you look at it through an NVG camera, you see that one half reflects light while the other half absorbs it.
In a sense, then, NIR-compliance is simply an additional layer of camouflage atop your garment’s existing pattern.
How clothing is made NIR-compliant
Now having cleared up the falsehood of dismal NIR performance being the fault of the camouflage patterns, we can move on to tackle another important issue.
As with other questions, you have to start at the beginning. In our case, the starting point is the fabric. PolyCotton and NyCo are very comfortable and durable fabrics—that’s why we use them. And because they perform so well, it would be unreasonable to seek substitutes in the quest for improved NIR performance. Instead, the smarter way to go is to look at improving the good fabrics we’ve already got.
It so happens that there are multiple ways of extending a fibre’s performance in the NIR spectrum. Namely, they are:
Modification by additives
In the last segment, you can find a large list of additives, but amongst them most notably dyes. As briefly mentioned above in the section “NIR defined,” NIR spectroscopy can be used to analyze chemical bonds; here, too, chemical composition comes into play. Chemical bonds play a major role in fabric absorption regions and can be modified to make the fabric more useful. By adapting them we gain what’s needed to achieve what we believe is the perfect camouflage.
“So let me get this straight,” you say. “Are you telling me that Ranger Green can be NIR compliant?” Yes, that’s exactly what we’re telling you. In fact, the U.S. army sparked a big push in CORDURA® 6,6 nylon filament by requesting an NIR-compliant desert-suitable uniform.
TrueLockTM EP technology was invented and provided the compliance needed for that uniform. TrueLockTM changes the fibre’s IR signature in the manufacturing stage, making that signature inherent to the fabric.
Image Source: cordura.com
TrueLockTM is not the only way to achieve low reflectance. But all other approaches are tied to materials and not to the patterns themselves. Remember, NIR compliance stems from the fabric itself, not the visual camouflage you see with your eyes.
So the short answer to the question of how to make NIR-compliant clothing is use the correct fabric.
In modern tactical theatres, operators trying to stay concealed have bigger things to worry about than NIR compliance. For example, FLIR and other advanced detection technologies. Those work by exploiting another human flaw—body heat.
But that’s a whole other topic, and one we’ll tackle in the future. Meanwhile, we’ll continue to create camouflage garments in compliance with current military standards.