Do space blankets block thermal imaging cameras?

anyone who has any actual experience let me know.

Not really, but it does change your surface emisivity and reflectivity. It also adds to the native environment an obviously forign object, so you are replacing one conspicuous object (you) with another.

Every time someone asks how to evade thermal imaging on this forum a bunch of people that have see something on TV or read something on the Internet pipes up so expect a bunch of myths to be posted here shortly.

If you like, PM me and I'll tell you of a couple of techniques that work very well.

reply to post by dainoyfb


I think you should just post them here, heh... What do you have to hide?

reply to post by theblackirish7


dainoyfb makes valid points. the most one could probably hope for is to distort an image. you're better off growing in several remote locations than trying to mask the crib.

In Hot Tips & Cold Shots.Fieldcraft.Thermal Detection, there are some
pretty gloomy postings about IR detection. As an
electrical utility thermographer, I might shed some light (pun intended) on
the subject. To qualify this, I am using the latest (I
think) commercially available FLIR product, and am a level II thermographer,
(total formal IR training: 2 weeks-experience
using IR equipment: about 5 years.) I believe I am at least familiar with
IR. Granted, my life is not depending on avoiding IR
detection, so I guess I can have my opinions pretty safely. These are my
observations about IR imagers using civilian
equipment and are.. "just my opinion". It's up to you and yours to check
them out in your world.

This is WAY brief, believe it or not. Anyone interested can email for
more. This is about THERMAL detection, not IR
illuminating sources for "starlight" scopes.

IR is not Xray, Hollywood bedamned-it cannot detect a differential heat
image through common solid materials, plastic
film (black or otherwise) being an exception. However, a good imager system
can see through holes in a masking material
("IR masking" camo net). And if you are inside a dumpster, bodyheating the
bad guy's side, he can "see" the hot spot on the
dumpster's outside. But if you are not leaning (heating) against that side,
he can't "see you". Your body heat will not be
detected behind most readily available unholed blinding materials if you are
not differentially warming/cooling those
materials or allowing your own IR to reflect off of something behind/over
you. BUT, if the shielding materials are alien to the
surroundings, the material itself will probably stand out. See below.

Glass will not allow your THERMAL image to transmit (pass) through; same
as the dumpster scenario. The lenses of IR
imagers are made of exotic nonglass materials because of this.

Every piece (cluster) of matter, including gasses, emits IR if it is
above Absolute Zero (minus 459.69 degrees F). The
warmer a body gets, the more IR it will emit. Eventually it will enter the
visible spectrum as it gets "red hot".

The surface of a piece of matter is where IR is emitted. Altering an
object's surface will alter the rate at which IR is
emitted. Stoveblack is a classic example.

Materials physically different from each other will likely emit IR at
different rates. BUT the differences may be very slight.

IR imaging (read DETECTION) depends upon two objects having one or more
differences in Temperature,
Emissivity/Reflectivity, and Absorption of the compared objects. For this
application, we can forget about Absorption, and
you should all understand Temperature. Now, E + R = 100%, thus the more
emissive a surface is, the less reflective. If two
dissimilar objects are at the same temperature, a high E will "look" hotter
to an IR imager than a low E, thus forming an
image. Objects with different Temperatures and the right E's could "look"
the same, thus forming NO image. Two objects
with similar temperatures and similar emissivities will present an unclear,
poorly defined image. Herein lies your IR strength.

Here are some Emissivity values for a few materials, all in percents,
all plus/minus a point or two. These are for short
wavelength commercial imagers and may vary slightly for long wavelength/long
range military/LE equipment. Military techies
should have similar emissivity tables for your equipment.


Human skin
: 97
Black vinyl electrical tape
: 97
Surface sprayed with Dr. Scholl's aerosol foot powder
: 96
Water
: 95
Rubber, black, hard
: 94
Glass, smooth
: 94
Plywood, raw lumber
: 90-95
Most painted surfaces (NON aluminum paint)
: 90-95
Aluminum based paints, depending on formula
: 30-50
Oxidized (blued, parkerized) steel
: around 90
Snow
: 82-85
"Most" organics (vegetation)
: around 80
Cloth, untreated
: around 80 (Cotton
was a plant too)
BDU fabric, treated
: ????????? I
would like to know.
Sand
: 76
Clay
: 40
Gravel
: 38
Aluminum, bare and "shiny" (read "spaceblanket")
: under 10


Note the materials that cluster around 95, 80, 40, and 10

Now, to apply IR-101: In all of the scenarios below, remember that your
body (or ANYTHING above absolute zero) emits IR
in ALL directions. If there is a reflective object behind or beside you, it
will pick up your IR and reflect it like you were a light
bulb. Whichever situation and methods you use, if you have the opportunity,
have an ally check you out from a flank with
your best IR detection equipment. Or get the flyboys to check you out with
FLIR's namesake. Do this by day AND night, as
the sun will do weird (but predictable) things to the differential temps.

The BEST way to protect yourself from IR detection is get behind/under
what is already there, and DON'T change the
temperature of it. Since you obviously have to see and perhaps reach out,
do so through the smallest portal(s) you can
handle. Those "man-sized" targets detectable at 1100 yards are just that -
man-sized - not the size of your nose and right
eye. Remember that glass reflects some IR (100 - 94 = 6%), and the sky
(space) is cold (approaching Absolute Zero), so if
your scope is reflecting not sun, but sky, it will look COLD. If you have
on a scope sunshade that is hot, the internal IR of the
sunshade will reflect out as HOT.

I believe the GI Woodland BDU's are treated with an IR emittance
reducer. If so, the "cloth" E figure in the table will
change and you have to adjust for the following discussion. Or obtain
untreated camo fabric or defeat that treatment (starch,
I believe). The IR reducing treatment makes sense for a situation where the
woods is cooler than 98.6 F. I hope the Desert
Daylight BDU's are NOT treated, but the nighttime anti-starlight smocks
probably should be. If your BDU's image "cold"
against hot sand, you are just as "seen". I trust the techies were aware of
this, and have specified correctly. But you need to
confirm by looking through your equipment at your buddy against some typical
backgrounds.

It has been reported that "fresh" BDU's do indeed have an IR treatment
that fatigues (pun) with laundering in "brightener"
detergents. As a hunter, I am aware of the UV problem with animals with
good night vision (is it an overabundance of rods, or
cones, in the eye?) and there are detergents available via sporting goods
stores that do not contain brighteners. If you need
to maintain that BDU treatment, you might try that. But again, look at your
buddies with your equipment.

Now, in sand or vegetation (E = 76-80): If you HAVE to have artificial
cover for situations where your clothing will
approximate the temperature of the surroundings, you want to expose matching
temperature "stuff" with a similar E (around
80). Cover as much of your skin (97) as possible with cloth (80) (remember
that I don't know the E for treated BDU's). But
also remember that sweaty cloth in a hot, dry background might look cold due
to evaporative cooling. If you are in a hot dry
situation, a tented, solid (not net), dry camo fabric applied as a screen
might do the trick for IR. (Remember, same T, similar
E). Visual is another problem. Keep the outlines irregular for both IR and
visual. Square stuff in a curvy world stands out, no
matter the technology. Fresh local vegetation in front of the screen will
help both.

Camo face paint is PROBABLY a high emitter, similar to regular paints
(90-95), and sweat (water-95) is for sure. You really
have to keep that face behind something. I don't know what a synthetic ski
mask would have for an E, but I bet it is below
97. A plain old cotton tee shirt mask would work, but remember the
wet/dry/cooling problem.

Black ANYTHING is a good emitter. Blackened steel barrels, synthetic
stocks, and painted surfaces (all E's in the 90's)
should be cloth wrapped for IR and visual both. Black SWAT uniforms
probably have a higher E than camo. You need to test.

Dry rubber boot soles (94) are nearly as hot as your face - sock 'em (80).

Old cut local vegetation will be drier, thus HOTTER due to lack of
evaporation.

The name of this game is to keep both the Emissivity and the Temperature
of the screen and clothing the same as that of
the surroundings and keep those portals small.

If you are on bare clay or gravel (38-40) and are worried about aerial
observation, dig in. Cover yourself with almost
anything sufficiently rigid and then cover it with at least a thin but full
layer of the local "dirt". This will match the E's. Once
the moisture of the new cover layer equals the moisture of the surface
around you (evaporative cooling), you will be in decent
shape IR wise. Remember that these low E materials have a high
Reflectivity, so block your own IR from getting out from
under the cover. If there is a chance your body heat will affect the top
surface of the dirt cover, use insulating material
between you and the bottom of the "roof" to keep it the same temp as the
ground around you. Foam board or sleeping bags
will do that. The most critical times of day for this hide would be as the
sun changes, because rapid heating/cooling of a thin
layer of dirt will show up compared to the slower heating/cooling of the
intact soil masses. If you can set up in a shaded spot
where this will not occur, you should be in decent shape. If there is no
shade, make the cover layer thick to create a heat
sink approaching that of the surroundings.

If there is no threat of aerial observation, and it is only a frontal
threat, a "wall" of local dirt with small portals would be the
best bet.

Any new foxhole will print either hot or cold depending on the season
and surface temperature, even if the surrounding soil
is bare. The deeper soil temp is probably closer to 55 F than the surface.

On snow (82-85), build a snow fort or tunnel in and make small portals.
Try to dust loose snow to duplicate surface
texture. Pray for new snow. If you wore an aluminized face shield behind
that snow fort, it would reflect the "cold" off of the
fort, and cover your hot face. This might be a shiny side application of
the space blanket, and could be worth testing. Water
(95) is your breath when it condenses. And it is warmer than the snow.
Only thing I can think of to do here is breath through
a ski mask and let it condense before it fogs up over your screen.

As to "space blanket" applications: there might be some, BUT. If you
are using the shiny side toward you to keep your IR
from getting out, remember that the backside of it is probably not a good E
match to the surroundings and it will heat/cool a
lot differently than most natural things around you. If you are trying to
put the shiny side out angled down to reflect the IR of
the terrain right in front of you, there would be a 10% reduction in the
reflection, more if it casts a shadow. If the shiny side
is out and up, it will reflect the cold of outer space (or the heat of the
sun) - and it is going to look REALLY weird to visual and
starlight in EITHER case! I cannot think of a space blanket application
that I would stake MY life on.

In an urban situation, you will have lots of "normal" IR blockers to get
under/behind. Just remember that you are an IR
light bulb on the cold surfaces behind you. You cannot casually set up back
in the room shadows of a windowless building
anymore. Remember, glass will NOT pass through (transmit) your IR image.
BUT, glass (94) has a high emissivity and will
show its surface temperature rather well. If you are near the window
warming it with your breath, you will reveal yourself. If
you had a small barrel portal through an otherwise intact glass window, you
would be IR blocked, but visually seen. A loose
pane of glass back in the room shadows might be a possibility, especially
for a spotter. If the room is painted (90-95) and
warm (approaching 98.6 F), you might blend in IR wise. But if there is one
warm window/room in an "empty" building,
something is amiss. The painted walls behind you might not reflect your IR
really well, but a metallic light fixture might blink
every time you turn your face toward it. The best I can imagine is forget
about the "room" and get behind/under something
that should be there - sofas, chairs, drapes, etc. and keep your portal
small.

None of the above CONCEALMENT strategies are easy; none are guaranteed
to make you disappear to an imager. But they
will all help make you a less vivid IR image, thus less detectable. IR
imagers may or may not have an adjustment to key in
the emissivity for scanning and reading temperatures. I doubt military/LE
targeting devices would have that - you don't care
what the actual temp is, you just want to see a picture. Military/LE
devices probably have a temperature range adjustment to
scale up/down according to environment. They probably have an adjustment to
set the sensitivity - the difference in
perceived T to go from black to white (dark green to light green; whatever).
If this is finely tuned, it is like upping the
contrast on your monitor.

There is one comforting thing to consider: unless you are in the desert,
there are a lot of different "things" around you,
each of them with a slightly different Temperature and Emittance
combination. If you can make yourself "nearly" match the
most common IR surroundings and the sensitivity is set very high in order to
pick up your small T/E difference, the other guy
is seeing a lot more clutter around you, so your image will be just one spot
on the Dalmatian.

For the Ghillie fans: A man sized wad of only burlap and jute rope at
98.6 F plus or minus a few degrees will have the same
E all over it. But if there was some leafage from an IR blocking camo net
on one shoulder and a splotch of shredded BDU's at
the waist and some foreign force camo material shredded in there somewhere
in a cluster, all well supplemented with local
veggies, from an IR standpoint it would look like a pile of dissimilar
"stuff".

If you have gotten this far, perhaps a little DECEPTION is in order to
up your advantage.

Remember that "Sarge WILL find something during an inspection, so ya
might as well give him something so he will stop
looking." If you want to determine if indeed IR detectors are out there,
you might want to give them a cowboy hat to shoot
at. I don't know what the E of a bare GI plastic canteen is, but if you
either wrapped it with Scotch 33 electrical tape (97)
from a demo/como kit or sprayed it with foot powder (96) from your ruck, and
had 98 degree water (coffee? Body heat?) in it,
it would make a darned good human face (97) to a distant IR imager. Topped
with a BDU hat and moved about on a stick
behind some intentionally inadequate screening after dark (by somebody else
behind that cowboy's large rock), I suspect you
would soon know the targeting capabilities of the opposition - and also
acquire a muzzle flash. A piece of most anything
warmer than the terrain drug remotely through the grass at night should get
IR attention. Just don't pull it all the way to your
position. But you get the idea.

If you want to just give him/them something to worry about, scatter some
old tire shreds (94) around at points distant from
your position. They will look hotter than most surroundings when they are
actually the same temperature. Plus, they will
heat up more during sunlight, and hold their temperature for quite a while
into dusk. If you can make them move a bit, so
much the better. If they are behind intentionally poor screens, thus not
visually or starlight identifiable, so much the better.
This would be a great application for decoys specially made for the
purpose - a visually camo'd, high E lollipop on a spindly,
flexible stick.

One of the new IR illumination chemlights would do something, but I have
no experience with them. I suspect one of them
tripped off in front of or to the side of your position, yourself in a
shadow from it, would blind any thermal imagers looking at
you - like a trip flare would blind a starlight. Obviously this would be a
defensive action.

There have been some pretty impressive demonstrations of the
capabilities of IR equipment. And it is indeed impressive
stuff, but it ain't magic. It can image warm footprints on a cold roof, or
a "ghost" where you leaned against a cold wall and
walked away. But those images fade pretty quickly - faster than the grass
will spring back up on your trail to a nest.

I believe that if one person takes the time to study and understand the
theory of IR systems and applies it to likely
circumstances in his world and does it better than the other guy does, the
first guy has an EXCELLENT chance of being the
winner. That is true for sniping or bidding on a roof inspection. Even an
unfavorable tilt in sophistication of equipment may
be overcome with intelligent application of ingenuity. And it won't take a
lot of formal training. After that, it is experience
behind an imager. In your case, looking at your buddies in drill hides, and
correcting each other's errors. I grant you that my
"thermacam" is not a military targeting device, but if your life is
professionally depending on IR avoidance, I hope you have
access to IR theory training and support along with the opportunity to drill
with your own imagers.

A rambling closure:

Overheard among the French crossbowmen at Crecy, 1346AD: "If we go
against the Smoking Demons, we will die."

Letter from a Confederate camp, 1864: "The Yanks have put spectacles on
rifles. There ain't no way to avoid a bullet from
a mile away."

NOT to be uttered by my youngest son, USMC Security, Kings Bay NB, 2000:
"If they've got IR, we are &^%#(+'d!"

If you may be exposed to a "new" technology, you just have to learn it
and apply it. Like you did for visual and starlight. In
fact, most of those old rules apply to IR: Irregular outlines.fresh
vegetation.local materials.etc. The only real new rule is
"Similar E - Similar T". Now, get with some equipment and TRAIN, DRILL,
EXAMINE, Train, Drill, Examine, train, drill, examine.....

Oh, is this about growing. I thought you wanted to know about military techniques.

When I'm looking for grow ops the first thing I look for is a hot transformer on the poles in a neiborhood. This is because the draw from a grow op at night is unusually high causing the transformer to heat up and stand out from the rest of them. This way I don't have to check every house in every neiborhood.

Then I look for a house on that street that either stands out because of an overall high temp, part of it stands out, or the electrical conduit feeding into the house is particularly warm or there is a surface near a vent that is being heated by exhaust air.

These are easy things to hide and if this is what you are asking I'll happily share here.

reply to post by AtlantisX99


Where did you copy that from? I don't see proper credit as per the T&C?
What I do see is a lot of... well, impractal BS. Maybe you should stick to what your experience tells you, not what google does.

Originally posted by dainoyfb
reply to post by AtlantisX99

 

Where did you copy that from? I don't see proper credit as per the T&C?
What I do see is a lot of... well, impractal BS. Maybe you should stick to what your experience tells you, not what google does.

I would say well done for noticing a copy and paste, but thats pretty obvious. As for calling it BS? you don't really know what your talking about and if you can find this using google, post the link, because that would impress me.

reply to post by AtlantisX99


I use thermal imaging in the field for military applicationans. People that have seen my posts here have come to realize this over time. This is because I design the technology. Do you have military field experience with thermal imaging technology? This is not a good topic for you to have a show down with me.

Again, you are breaking the T&C without posting credit, unless of course those are all your assumptions?

reply to post by dainoyfb


You are assuming that I do not have the relevant knowledge and experience and if you disagree with my personal findings, that is fine, just don't assume that I am stealing.

Originally posted by AtlantisX99
reply to post by dainoyfb

 

You are assuming that I do not have the relevant knowledge and experience

It's not an assumption. I can tell by what you are posting.

Here, I threw a video together for you. Sorry about the poor audio, etc. I was in a hurry. Anyway, don't worry about what face paint you are wearing, it won't make enough of a difference.

The Iraqies have been evading high-end thermal for nearly two decades now with no more than heavy, ragged cut blankets. We can one-up them here with synthetic or down fill sleeping bags.

Also, of the best materials for hiding a thermal footprint (so long as your not touching it) is tent nylon. this is because it is thermally opaque, has a low thermal mass, and is reflectivly neutral. So a low, well concealed tent is an excellent thermal shelter too.

Also, use your environment when possible. Pine and spruce are difficult to thermal image past. early evening after a sunny day is also difficult. As temperatures in a scene equalize throughout the night or after a cloudy day imaging becomes much more effective.
Enjoy.

Direct YouTube Link


I guess the lesson here is: put away the thermal imager and get yourself a cat.

Remember that tent I mentioned? Here is a thermal image I took of a tent with two people sleeping in it (creepy, I know). Notice how the outside surface is the same temperature as the ground and the trees behind it. This forces the operator to recognize targets by shape instead of by an unusual heat source so if the tent is well covered by foliage it's practically an impossible find. By the way, that hot spot at the lower right is a mouse trying to get in.
[atsimg]http://files.abovetopsecret.com/images/member/b4073f032924.jpg[/atsimg]

Originally posted by AtlantisX99
if you can find this using google, post the link, because that would impress me.

Ok, here it is.
www.onlinepot.org...
Do I win a prize? I would rather just see the mods remove your illegal and obviously full of garbage post. You are a fake. Please go away.

wow thanks for the info this gives me a much better understanding of the basic operation of thermal imaging

Another thing to be aware of is how thermal imagers see gasses such as your breath or exhaust from a grow op.

The atmoshere is for the most part completely transparent in the spectrum that thermal imagers use. It has to be in order to see anything at a distance. In fact, I can see the moon radiating or reflecting heat with my thermal imager (except when there is a lot of moisture in the upper atmosphere such as clouds). What this means to you is that thermal imagers cannot see hot air as opposed to cold air. The videos on YouTube of a thermal imager catching a person farting are faked. Occasionally you will see circumstances where the thermal imager will apear to see hot air but it is steam or particulate matter carried up by flames.

So there is no need to hide your breath or hot exhaust vented by a grow op. What you do need to hide is the vent or other surfaces which are being heated by that air.

Here is another thing to be aware of, especially if you are operating in an area that gets snowfall.

Footprints in snow remain very conspicuous, day or night, even for weeks, particularly in the the first months of winter. This is because when snow is stepped on it remains compressed which turns it into a thermal conductor rather than an insulator. This causes it to draw up the heat from the warmer earth below the snow, thus causing the footprint to glow. The same applies to snowmobile and vehicle tracks, even after another light snowfall has covered the tracks visibly.
[atsimg]http://files.abovetopsecret.com/images/member/cef112739441.jpg[/atsimg]