non-visual spectrum

[lutindiable]

is there a way of making an entire material out of some form of non-visual spectrum ink or dye?

 

i found this,

 

 

"To provide camouflage in non-visual range of spectrum, i.e., against NIR detection devices working in the range of 700–1500 nm, it becomes essential that camouflaging equipment should be painted/dyed with the pigments/dyes having NIR reflectance values similar to that of backgrounds in respective shades. Generally, the shades of vegetation and desert regions are confined to olive green, brown, deep brunswick green, light stone and dark stone colour, so it is required that IR reflectance values of pigment formulation must match with the IR reflectance values of these shades of the background vegetation or desert terrains.

 

An elaborate study has been carried out on these pigment formulations coated on cotton and nylon substrate materials. The study has brought out the reflectance trend of the formulations, role of each constituent pigment on the reflectance values and effect of dilution or concentration of pigment formulation on the reflectance properties. These studies would pave the way for preparation and optimization of various formulations with respect to IR reflectance values and their use for camouflage purpose in non-visual range of electromagnetic wave length."

 

 

but unfortunately thats where i couldnt go no further i couldnt find anything else on the matter, does anyone else know anything on the matter or know any more links on the matter?

[swansont]

What do you mean by "non-visual spectrum ink or dye"? Absorption properties? Reflection properties?

 

Your quoted material says that the camouflage has a similar reflectance as background in the non-visible part of the spectrum. Presumably, it also has similar reflectance in the visible, too. That doesn't mean it's inherently invisible, it means it's hard to distinguish from background.

[lutindiable]

basically colours that are out of our visual range, like uv or infrared, or something to that effect

[John Cuthber]

What do you mean by " way of making an entire material "?

 

All that article says is that, in the same way that things are camouflaged by making them roughly the same colour as the background, they can be camouflaged from the point of view of an IR camera by making sure they have the same IR reflectance spectrum as the background.

A fairly obvious wayto do this it to cover them with the same material as the background. For example, if you want to hide your tank in the desert, make sure it's covered with sand. If you want to hide it in the forrest, cover it with leaves.

None of this will help if the enemy has thermal imaging gear.

[swansont]

basically colours that are out of our visual range, like uv or infrared, or something to that effect

 

Yes, you can make things that look different in IR or UV than they do in the visible.

[swansont]

What do you mean by " way of making an entire material "?

 

All that article says is that, in the same way that things are camouflaged by making them roughly the same colour as the background, they can be camouflaged from the point of view of an IR camera by making sure they have the same IR reflectance spectrum as the background.

A fairly obvious wayto do this it to cover them with the same material as the background. For example, if you want to hide your tank in the desert, make sure it's covered with sand. If you want to hide it in the forrest, cover it with leaves.

None of this will help if the enemy has thermal imaging gear.

 

If it's equipment that's turned off, or doesn't generate it's own thermal output, though, then you need to make sure that the IR/UV properties of whatever is exposed are the same as the background, as well as the visible properties. Which is what the quote was saying.

[John Cuthber]

"Yes, you can make things that look different in IR or UV than they do in the visible."

I know how things look in visible light; how do things look in UV and how, unless your eyes are UV sensitive, do you know?

Seriously, what does that sentence mean?

[YT2095]

perhaps (and I`m guessing), he means something like if you dotted IR leds all over something, in the Visible it would quite ordinary like a Tank or something, but when looking it the IR only it may say "Eat at Joes".

 

I wonder if that would class as Subluminal advertising? (sorry, someone had to say it)

[Klaynos]

"Yes, you can make things that look different in IR or UV than they do in the visible."

I know how things look in visible light; how do things look in UV and how, unless your eyes are UV sensitive, do you know?

Seriously, what does that sentence mean?

 

He means if you used say an IR camera and then looked at it with a normal camera you could make the two look completely different. In the say way as if you limit your visual range to only blue and look at something then limit it to only red and look at the same think it can be very very different...

[swansont]

"Yes, you can make things that look different in IR or UV than they do in the visible."

I know how things look in visible light; how do things look in UV and how, unless your eyes are UV sensitive, do you know?

Seriously, what does that sentence mean?

 

In a similar way to how you see in IR; you use a detector sensitive in that region. Flowers, for example, often look very different in the UV than in the visible.

 

http://www.srs.fs.fed.us/4505/hanula/pollinator_studies/uv_photography.htm

 

So you may blend in in the visible, but if you don't reflect well in the UV, and your background does, you'll stand out in a UV picture.

[John Cuthber]

"In a similar way to how you see in IR"

I don't see in the IR; that's pretty much the definition of IR.

There is a difference between saying these things look the same (ie have the same visible reflectance) but don't have the same IR reflectance (which is common enough) and "these things look different in the IR" which only makes sense if you can look in the IR which you can't.

I know things can reflect IR or UV differently, even if they look the same. In fact, everything does. If you look at a large enough range of the spectrum then no 2 things will reflect identically unless they are the same material.

That's why I sugested using, for example, sand to look like sand.

 

I'm still trying to work out what the OP's question meant.

[swansont]

"In a similar way to how you see in IR"

I don't see in the IR; that's pretty much the definition of IR.

There is a difference between saying these things look the same (ie have the same visible reflectance) but don't have the same IR reflectance (which is common enough) and "these things look different in the IR" which only makes sense if you can look in the IR which you can't.

I know things can reflect IR or UV differently, even if they look the same. In fact, everything does. If you look at a large enough range of the spectrum then no 2 things will reflect identically unless they are the same material.

That's why I sugested using, for example, sand to look like sand.

 

You can, though, with the proper equipment. I have an IR viewer in my lab, that lets me see 780 nm and 852 nm light reflecting off of things (and would probably work out to about a micron). Thermal imaging takes you out to 10 microns or so. You can image UV, too, though the optics get tougher to do.

 

I'm still trying to work out what the OP's question meant.

 

As am I.

[lutindiable]

what i meant was, as we cant see either uv or ir cant a material be made that are somewhat out of our range of vision, so at a quick glance ya cant see it without special equiptment

[Klaynos]

what i meant was, as we cant see either uv or ir cant a material be made that are somewhat out of our range of vision, so at a quick glance ya cant see it without special equiptment

 

You mean like glass?

[BhavinB]

I think the OP is slightly confused in asking if we can make something invisible in such a way. The answer is no.