It does not matter what the surface is day or night, all they see is intense concentrated black.

Although they can see my green lasers as Green Day or night!

Cows sheep and horses looks like they can see just above 650nm

Nietzvision

Dr. Nietz worked with us on many visual genetic diseases that cause blindness in animals and humans.

I'm not trying to be argumentative, I'm trying to understand a topic that's throwing my brain for a loop.

As I understand what you're saying is that canines can't see the wavelength of a red laser as red but as you're describing, they see it as a super bright concentrated black dot.  Wouldn't that be the same as humans not being able to see colors in the wavelength of the IR spectrum, so shouldn't then humans see an IR laser as the same super bright concentrated black dot?  Obviously we don't, so there leads to my confusion.  

I don't even pretend to fully understand the science but I'm trying to logic it out based on your description. The only way I can make sense of it is to think that the "red" laser isn't projecting a narrow wavelength of color but to us is so predominately "red" that we see it that way, but if it was put on a spectroscope (if that's even the right tool) would show it as projecting other colors that were in the canine's visual spectrum.  And if a filter or a cleaner laser was used that only put out wavelengths over the canines visual range would it not see it at all, just like us and an IR laser.

Can you guys help me understand where my assumptions are wrong?

You should have some more gun with your FLIR

I swear some people (not picking on anyone here) refuse to believe me when I tell them black is not a color.

First, I have trouble believing that intense red or IR light would cause a "light vacuum effect" and produce the visual perception of blackness - the absence of light. I've been cracking up this whole time because the first thing that came to my mind was the part in "The Grinch Grinches the Cat in the Hat":

"Max, do you know what a lighthouse is? A lighthouse makes light - so, just for a lark, I built me a darkhouse. A darkhouse makes dark."

Oftentimes the investigation in a thread leads us to discover that the OP asked the wrong question, but not this time:

"Can coyotes DETECT ir light? I've lit some up and watched them come to my calls like they didn't notice it, or it didn't bother them, but I've always wondered. "

Even though the Cat in the Hat cannot see his mitten right in front of his face when the darkhouse projects on him he can DETECT that something is afoot. "Detect" is the important part. If the Grinch shined the darkhouse on me, I may not "see" the beam (because it's projecting the absence of light, from my perspective, and light is what we "see") but I can still "detect" it because it's presence is anomalous. I see an analog to this in physics where we see effects happening that we cannot explain, leading us to believe that something we are not able to directly witness is afoot. Sometimes the questions that arise self-answer, even in the face of a lack of viewable evidence. We know this to be true because later technology allows us to repeatably and reliably witness the causation that we previously only "predicted" and did not actually "know".

I know Michael Shermer is usually pretty weak on logic, but when he leaves his lame political baggage behind him, he can often form a cogent point. In the Feb. 2017 Scientific American he writes, "Imagine nothing. Go ahead. What do you see?" It's a brilliant premise. It's almost impossible to imagine "nothing" because our whole existence is surrounded and imbued with something. Can nothingness be measured? Can it be "detected"?

Keep in mind that I already agreed 95% to 99% with SkyPup before he ever posted - that the projection of IR light sources at coyotes is probably irrelevant - I just have trouble letting go of the last bits of doubt, and his arguments (not the biological evidence which is compelling, but the logic regarding perception that presents a conundrum) actually sway me the other direction.

Lets get back to the nuts and bolts: I personally blip IR for the purpose of flashing eyes but I don't run it full-time to provide increased resolution for the final moment of a shot unless the shot cannot be made without it. "Can coyotes detect ir light?" Under most conditions, probably not - under some conditions, maybe. That's my own personal opinion, but people that I respect disagree with me so I try to err on the side of caution.

The question is not whether or not "black" is a color - the question is whether or not IR (which some people posit is perceived by canines as "black") can be DETECTED by canines. I may not be able to see black but I can detect it's presence. When the logic processes in my brain are presented with the absence of color, they choose to regard the absence as "black" because "the absolute absence of color" is too damned inconvenient.

I have noticed that it seems my dog prefers to chase the red laser, than the green laser.

but never thought of it as a "black dot" 

The IR light issue based on the data is it cannot be seen by any mammals, I have never seen them spook at the beam.  But the light emitted from the source is clearly see by humans, Larsen electronics has the info in the link I posted showing the difference in the visible wavelengths emitted from the leds source of the IR lights they make. Now finding the wavelength of the light will clearly show if it falls within the range of canids.  If it does then they clearly see it as well, probably several magnitudes better because of their night adapted eyes.



Interesting explanation of vision CMvision

After all is said and done, no one and no one's night quarry is ever going to see IR and no ones dichromatic coyote, dog, or hog is ever going to see the color red.

No one is saying dichromatic canines species can see any IR, they cannot see any IR period.

The visual color RED is perceived by dichromatic canines as BLACK since there is no color perception of the visual color RED.

... and the source is an important point. This is not purely theoretical - the OP has a practical application and I doubt he cares regarding the difference between critters getting spooked by the beam and critters getting spooked by the source. In a practical application, there will always be a source present so that issue needs to be addressed to understand the full picture.

Let's not forget: we're primarily talking about coyotes here. They're a subtle blend of both genius and idiot - both a scientist and a savage at the same time. They do not operate strictly on instinct. They have many learned behaviors. Expecting two different coyotes to behave exactly the same way under two different circumstances (the reality of a field comparison) is unrealistic so, as simple as the OP's original question sounds, it is actually very difficult to prove the answer outside of the laboratory (where it counts).

Why do they see black, when humans don't see anything at all when viewing something that is in a wavelength above what we can see?  Why do they see something outside their wavelength view and we do not?

As an example, Humans and other animals have many genetic visual diseases that make them see different colors than what is real when their opsin protein genes have mutated such as red-green color blindness in humans that do not see real red or real green, instead they see grays or yellows.

Look at the sky at night, it is Black because you cannot see any visible light from it, there is all kinds of electromagnetic radiation that you cannot see there, but it is Black because there is no visible light you can detect.

The Sun has been the primary source of visible light for all life forms during the day for billions of years and rhodopsin opsin proteins evolved to transform that light into brain waves that allow you to see visible light.

No life forms living ever evolved the ability to see IR emissions from everything on the Earth since virtually everything here on Earth is radiating IR light all the time during the day and the night from the energy captured from the Sun during the day. The brain capacity to process IR light in addition to visible light would require a brain almost double in size for all the extra added visual information to be processed.

Ain't going to happen in another couple of hundred million years either.

That particular mutation would save a few of us some $$ spent on night time toys, but it sounds like a heck of a headache.....

Maybe a better way to ask my question is:
Why does a canine see anything at all if the laser wavelength is above its visible spectrum?  Whatever it is that causes that ability in canines to "see" that red as black dot, why don't humans have the same ability to "see" something they don't have the visible spectrum to see?  I follow your space is black description, but I'm unaware of any wavelength of laser that would appear as the same kind of black dot you're describing that the canines sees, as appearing that way to a human.

I'm baffled.  I see clear evidence the canine sees something, I have no problem accepting it as that it sees a black dot like your describe.  What I can't picture is how that works, and is there a human equivalent for it.......

OK got my 4 IR filters NEEWER brand, 720nm, 760nm, 850, 950nm.

All 4 stacked can't see anything outside in bright sunlight looking thru all 4 filters.
Looked at the sun using the roof edge to block it  then quick peek, I can see a very dark dot like looking at it thru welding glasses.
Not bright but I know the IR above 950 is getting thru all filters 720nm+760nm+850nm+950nm.
Nothing can be seen except the sun, which appears very dim dark dark red brown.

Now when I put all 4 filters on my t20 and go into a dark room I can see the led on low, med, and high, looking at the edge as I want to limit my exposure to the IR light, I do not believe that the t20 puts out more IR then the sun. But the led is brighter on low, not to mention med or high. How to filter out visible emissions if 4 filters including a 950nm does not eliminate it.

Any one explain this?
I tried to take a photo of the ir source with iphone it does not see it in well lighted room, I am going to try in dark room.





PIC of the sun with 4 filters using iphone 5 very faint as camera auto adjusts brightness look at surrounding black area to see the auto gain level is high. Camera is trying to make the sun look brighter because the filters have almost blocked it out completely.

1st       IR leds are bad emitting visible light but spectral curve from MFG does not show any?
2nd     Using filters that practically block out the sun looking directly at it. I see my t20 850nm light on low, med, high.
3rd      ? light is not IR it's magic light that goes thru 4 IR filters and is in the visible wavelength?
4th      Maybe my t20 light is so powerful it can power the planet, imagine all the solar panels I could light up, even melt the south pole.

I see what I see regardless of what I am hearing, but the it's a bad led theory emitting visible emissions will work for some.

I will stick with the 2 photon theory humans can see IR light. Leds are pulse width modulated which is switched on/off very fast.
https://phys.org/news/2014-12-human-eye-invisible-infrared.html

I also will work on the red laser magic black dot theory next.
I think they see a yellow dot, I will try and paint some squares different shades of yellow and see if I can hide the red laser dot from the dogs by pointing it at different squares to see which they cannot see. I think it's impossible to hide a black void on a yellow square.
If it hides in the yellow square well then it's not a black void , my first guess would be it's a shade of yellow.

Agreeing to disagree is always an option

I have no doubt that an IR light beam is invisible to mammals, but the source is causing something to happen that can be seen by critters and humans and it IS an IR emission.

In the end, IR is unseen by all and dichromates do not see red.

I've done the same thing with IR filters and a T20 light, it didn't change the red glow at all. It was very obvious to me after that, the human eye can see a small amount of 850nm wavelengths if the intensity is high enough. And to convince myself even more I stacked three 850nm filters and the red glow was unaffected.
I'm not convinced that a coyote can see a tiny, 2mm square black dot (if red looks black to them) on a black night. Gray maybe?

Stacking the filters adds to the blocking effect of visible light because you can't see anything.
I took a quick look at the sun and it was a very very dark small circle, so I know the filter works on visible light.
Heck it blocked out the suns visible spectrum almost completely.
But it can't block out the faint glow from the t20 850nm light?
But the you can't see IR light does not explain why the visible light from the LED is not blocked?

I send an email out to try and get to the bottom of this, hope it gets resolved.

Imagine a filter that only blocks the visible emission that is seen, screw it on and full IR power and no glow?
Simple notch filter may be possible.
Imagine IR leds no glow , no need for 940nm wasting 1/2 the power because gen3 NV sensitivity to it is 1/2 vs 850nm.
That is what I am looking for

It is not within the visible band, that is what is not understood here.

The IR filters would have drastically cut it out, just like they did the sun.
You can't believe the sun can be blocked out by 4 filters but the little dim glow can't be.

Think about this, you cannot see thru 4 filters all visible light is blocked

Think about it again you cannot see thru 4 IR passing filters its like darker then a welding helmet lens.

But it cannot block the dim visible glow?

The IR LEDs all have a normal distribution of wavelengths around the published wavelength down into the visible spectrum, so no surprise you are seeing visible  red, blue, purple, etc. even with a cutoff filter since the cutoff filter is also not an absolute and also has a normal distribution spectrum around its published wavelength.

IR Lasers also have a normal distribution of wavelengths around the published wavelength that is tighter but some brands are loose and lousy, others are tight and more monochromatic.

As a warning, looking at IR LEDs or IR lasers will immediately induce irreversible damage to your eyes, the least of which is crosslinking of the crystalline proteins in the lenticular sac resulting in permanent cataracts. Also the corneal epithelium covering your aqueous humor is about twelve cells thick when you are born and maybe 7-8 cells thick by the time you reach 45 yrs of age, killing a couple of the ones you have left is always a bad idea and often leads to the "crushed grape" effect, and then having your cornea and lens focus the IR onto the most dense foveal photoreceptors of your retina is always a real bad idea.

I am sure. I have always remembered that when you pointed this out to me years ago. I try to limit exposure.
Only peeked at sun once and won't do it again even though it's visible wavelengths were almost totally blocked out.
Must be a powerful led side band emission  to compete with the visible portion of the sun.

Ok see if this makes better sense, I have a 3watt white led light wattage is wattage 3watts IR or 3watts visible will be comparable.
The 3watt white LED light is totally blocked by the filters 100% but a visible side emission from a 3watt IR led makes it thru.
The visible side emission cannot I repeat cannot have anywhere near the power of the 850nm main emission beam.
So why does the visible side emission of the IR led make it thru the visible blocking filters and the full power 3watt LED gets blocked 100%.

BTW, one of the first symptoms of laser or LED eye damage from IR is the inability to distinguish colors since the cones in the concentrated fovea have been fried....

I want to just stress what SkyPup says here. Be careful with these things - they aren't toys. I have some higher power stuff that sincerely scares me. The fact that the light is generally not visible makes a lot of people lazy about eye safety. All of this is readily measurable - reliably and repeatably. There is no real argument in this segment of the science. Seriously - be careful. Don't stare down beams to the source.

I will take a color test tomorrow as I was looking at the circle with colored dots at work and was one of the few that made out all the numbers to test for color blindness, and I am no spring chicken the big 5ohhh this yr.

Thanks!
I am careful it's the stupid I am worried about
I started with 200mw IR lasers and have not blinded my self yet, didn't know the color vision would be effected first.
As far as I know I have no color blindness. Better hearing then everyone I work with and seeing the colored numbers was no problem.
A couple guys could not see certain of the number patterns within the circles.

I need an optical spectrometer from 200nm -1800nm to find the notch filter needed to have no glow IR leds.
I bet the notch filter will not be within the visible spectrum and the glow will no longer exist.
But until its done it's all just typing on a keyboard.

I was going hunting but got bummed by the stacked filters not have any effect on the visible emissions of the light.
I want high power no glow  notice now wearing IR glasses

That's golden. So the likelihood that someone has suffered damage due to IR LEDs or LASERs is small if they are asymptomatic with regards to the inability to distinguish colors? I've been careful but I've made a couple of stupid IR mistakes. This eases my mind a bit, knowing that there is a sort of a benchmark that is readily witnessed.

+1 on that

The human eye is just an extension of the brain through the optic nerves and being neural tissue, none of it regenerates, once injured it stays that way.

The eye is also immunologically distinct from the immune system of the body and has some very weird not well understood immunological oddities. One of them is a relatively small benign injury to one eye can release S-antigen which then causes a disease termed  Uvetis and results in the same damage to the other uninjured eye. If you know someone that has Uvetis or has experienced it, you would understand how devastating it is.


https://nei.nih.gov/health/uveitis/uveitis

Moral of Story is do not fuck with your eyes.....

Have used 100 mw ir lasers and I am not blind yet. I do understand the restrictions though. I get it but wish we could have some training set up. Nothing better than a high powered laser ir illuminator. I am aware of the damage they could cause from nefarious individuals.

According to Osram it doesn't put out any visible light.

Attached File

That is a good normal curve but most likely it puts out some visible light at the bottom of the curve.

Remember, a healthy human that has not fried their eyes with IR can see a single candle flame from a distance of 1.6 miles under good conditions at night.

I once sat, watching a dim light jump erratically on a very dark night. It finally got my full curiosity piqued, so I walked to the source of the light to see what it was. It was someone smoking a cigarette just shy of 1/8 mile away. That was just the ember.

I'm not saying that the curves aren't generally accurate but I've spent time in front of a curve tracer doing failure analysis and those curves look pretty sterile. They look like "target condition" shots. Typically any semiconductor curve will have anomalies - and the anomalies may be the crux of this entire conversation. I can't remember ever seeing a curve from a manufacturer that looked the same as what I saw on the curve tracer. I don't blame them too much. The curve they publish is a sort of advertising. I don't really expect them to highlight their product's shortcomings. The first time I sat in front of an oscilloscope I had all sorts of stupid questions because I was expecting the waveforms to look like the ones in the textbooks. The reality is that there is almost always overshoot, noise, etc.

...so, yeah, I think SkyPup is saying that the product probably does not perfectly follow the published curve and my experience is that he's probably dead on right with that.

It only shows 700nm up, not full visible spectrum, but I think if it were visible light like my 3watt flashlight the IR filters would have blocked it just like it did the flashlight. After all I would not think the spike would exceed the target 850nm main beam or in this case the only beam. I have a 2x4 sheet of IR passing lexan you cannot see thru it, the 850nm glow appears transparent to the 850nm sheet with the 4 filters attached to the light. This is what does let the Kool-Aid  go down

The 950nm filter does seem to have a greater effect then the other 3 filters, I expected this as it is above the 850nm. I have not looked at it with gen 3 to see how much it reduces the light output beam. The issue is why would visible light be blocked by the IR filters, the white 3 watt flash light be blocked as well, and the sun, but the dim weak glow prevails? Is it possible the dim weak glow is 850nm or a 1/2 wavelength that is perceived by the cones within the eye? Because as of now the 950nm filter reduces the glow but reduces the 850nm beam. The 2 go hand in hand so far. Next move narrow 850nm band pass filter only the 820-910nm will pass thru it. If the glow prevails it points to the 850nm as this will pass thru. Then it's check mate nothing can be done but turn the light off

On a side note I just got in a 3watt 940nm light I can't even tell its on, no glow what so ever. Until your eyes adjust to the darkness then you can see a very very dim glow.  Now to test how it works with the gen3 NV. After running it a while I would say for under 25yds its ok. The 950nm filter on a t20 set to high was not as bright as a t20 on low with no filter. So the 950nm IR pass filter cuts the glow by 1/2 but reduces the power by 2/3. Not an option I would use, so 950nm filter is for testing only.

When looking at the pattern of the IR led array when at full focus you can see the array pattern of the led.
Rows and rows of 850nm light producing mini leds, well if the light output is emitting the light from hundreds of these mini leds at the same time. The odds of 2 photons hitting the photoreceptor  increases.  Is this what is causing the photo receptor to perceive it as visible light from the source? The dual photon strike like the experiment with the IR lasers? Because a visible light blocking filter does NOT effect the very dim glow, but blocks the sun and a 3 watt white led focused flashlight.

I assume you are not adequately controlling background illumination and your eyes are self-adjusting. Human physiology makes objectivity difficult. The primary concerns are usable output and visible signature WHEN USED IN THE APPLICATION ENVIRONMENT. Do not spin your wheels worrying about how something seems to work (or not work) outside of the application environment.

If neither we nor the critters can see IR, but we are seeing SOMETHING, then we may not be seeing IR - but the something we ARE seeing is potentially also being seen by the critters. That is in the spirit of the original question by the OP. There IS a visible signature at hand (whether or not it is IR - I really don't care). Hardware modifications may or may not be a solution - technique of use of currently available IR sources may provide some or all of the necessary improvement... but definitely stay the course - reducing the inherent signature of the device is always a laudable goal.

I hope, at this point, that it has become clear that I do not have a gripe against Science generally. I have a gripe with people using data to attempt to prove true what is patently untrue and that I am able to plainly witness. There is no such thing as "Settled Science". Science is an infinite frontier. "Settled Science" is just another name for bigotry. True Science has persevered through the centuries, blasted previous data, and crumbled many long held beliefs - but it never tries to tell you that what is plainly happening in front of you is an illusion.

Maybe the OP's question should be reworded:

"Is the visible signature that is produced by IR illumination tools as readily detected by coyotes as it is by humans?"

That might get us better on track. Some of us are splitting hairs about what is visible and not visible, while some of us are concerned about the obvious visible signature - yet we are treating it as if it were the same conversation.

Yes, the fact the IR led source is visible by humans is fact.

The wavelength of the emission is not known by me, other then the published data for the IR led.

Which does not show any visible light !

IR pass filters that block the sun almost 100% and 100% of the light emitted from a 3watt white led flashlight (which is similar power output of the IR led used) does not  block the dim glow from the IR led.

IR 850nm passing lexan does not lower the glow from the IR led, all visible light is blocked as I cannot see thru the sheet.
But the dim glow of the IR led looks the same, just like you put a red led behind a clear piece of glass.

If the 850nm wavelength is the glow humans see, the process which makes it happen means nothing to me only the fact that it is happening. Then IR lights will not be 100% stealth, I only have need for a 0 visible emissions IR source for 50yds and under when moving thru wooded, brush terrain as thermal is ok but I prefer I^2.

Others think the thread is a dead horse but I cannot escape the sneaking feeling that I am about to learn something. Hard_ware is on to something whether or not any of us want to accept it.

I sent out a few emails to sources that have the equipment to validate the emissions of the t20.

This should put the visible glow question to rest, it is visible and it's from the IR light.
Just a matter to show that no visible emissions are emitted then it only leaves the smoking gun
Only way to stop it is to turn the light off.

Looks like the Q14b or the IR patrol w300 is in my near future

Agreed, something is happening here that we can't seem to explain.

The question becomes, what experiment can be done to explain it?

With same explanation , the emission is a visible side band with no proof, MFG spectral chart only shows 850nm curve.
You can't see IR light but IR lights all glow everyone knows this.

Why several stacked IR pass filters block all visible light but the IR led continues to glow.

All still unanswered

Human infrared vision

Clearly explains the occurrence to me

I was hoping to find a filter to block the specific wavelength causing the signature, but since blocking all visible wavelengths didn't work it only points to the IR spectrum and blocking that defeats the purpose of having a infrared light.

If mfg would re-engineer the led array to sequence the emissions and not have simultaneous photon emissions IF  the 2po process is what is responsible for the visible glow a IR led source would be 100% invisible.
Things happen way faster then we can handle having photons sequenced would not change the amount of light that would be emitted, just lessen the possibility of dual photons see from the emission point.

The 940nm IR leds still glow, much much dimmer but they still glow.
I was using one last night, 3watt 940nm led.

The glow from led we all see, but the puzzling thing is it's not from visible emissions wavelengths , but we still see it .
Then how do we get rid of it.

I am sure you would like the torch to be 850nm 0 visible emissions with full power. Imagine the market.