TEST of Blood Tracking Flashlights!

Following. I’m new, but I bought a pretty large range of lights to try to blackpowder next week.

Nothing conclusive, with all due respect is because, it seems, a lot of people posting have no experience and are just repeating something they saw on TV or some place on line.

First of all UV only works with luminol or on TV shows. Without luminol or the like blood looks black under UV.

Secound blue LEDs don’t work without running a red LED at the same time….if you have a blue LED or a blue filter for a white LED light, you can confirm this yourself.

Blue lens do work with incandescent light - this is easy to test for yourself if you have a reasonably powerful incan light and something to use as a blue filter - just don’t expect the blood to jump out like a flashing neon sign, you need to look close and bright red (and orange) will stand out as while other colors will look blue or black. BTW there is nothing magic about blood other than the bright red color of fresh blood standing out - anything of similar color works the same way. Dry blood once it darkens will not stand out.

xxo

I think you nailed it.

Like anything it takes work/practice. Add to that our eyes are all a little different. Things like color blindness, ambient light, and perspective/angles can make a big difference.

Thanks. Good information for me. I am trying to run down information on what different UV wavelengths are good for, although 415nm is not really UV. Your information is consistent with xxo. Strong absorption at 415 will make the blood look black. Good for a carpet or floor but probably not too useful in the brush.

Precisely. I’m colorblind, and as such, have really struggled with tracking in the few times that I have needed to do it because the red just doesn’t stand out at all to me.

Another problem is that I’d love to build and test a couple different lights… red+blue, different wavelengths, etc, but I don’t have blood just hanging around that I can test with. I suppose I could go play with my chainsaw for a while and hope for the worst :disappointed:

It really is trial and error… the amount of leaves on the ground, the amount of moisture on them and the time of day makes a huge difference. I have had to track a small number of shot deer over the last 35 years. With the advent of good leds, I have started carrying several to each hunt to test on the splats and puddles after a kill. For me, with my crappy eyes and well focused 7 bin XM-L2 has worked well and as thing progressed I built and tried others. The 3500k Nichia seems to also work very well, I used the sw35 R9080. I think the R9080 is what made the difference, reds really pop. I really have not tried cooler bins, I tend not to like them, they give me a headache. Also the cooler bins are hard to find with higher cri and red, that is R9? rating. Once it is dried… good luck.

good info
my best LED to make Red Pop is a 3500k E21a, its even better than my 3500k 219b 9080, and my 4500k 219b 9080 sw45 and sw45k

focus on the color of the two vertical sets of Red Beads in the middle

disclaimer, in real life the advantage of the E21a is more obvious than in those pics
also the E21a is in a reflector, that has a hotspot, which confuses the camera more than the triples

The E21a is difficult to get a good beam from a reflector, but can be fantastic with a pebbled TiR… Clemence has a board on his site…

Maybe a tracking light benefits from a diffused beam with no hotspot, for close range inspections …

Dr Jones had a novel idea in his rgbw FW, green & blue leds on and blink the red led at the same power level. I never tried blood tracking but it did work for anything red, made it flash at you.

Do the goggles need to be yellow or is orange going to work? If they do need to be yellow would a set of just yellow colored galsses like this protect my eyes from the 415nm wavelength? Or do they have to be special a type?
https://www.amazon.com/Protective-Glasses,-Protection-Equipment-Technicians/dp/B07SZ7WQ2Y/ref=sr_1_38?keywords=yellow+laser+saftey+glasses&qid=1572042992&sr=8-38

Matt (and others) check this out…

This is essentially what we used at the PD.

Any polycarb naturally blocks the harmful UV spectrum. Tinted glasses are to increase the contrast of fluorescing objects vs the visible UV from the light.

Polycarb on its own seems to block lower wavelengths like 365nm quite well, but I have noticed with 395nm when I cover the sensor on my light meter with clear glasses about 30% or so still passes through. Using my orange glasses it drops to almost flat zero. I’ve seen many colors of glasses so I was not sure if they were wavelength specific. I will go ahead and order the yellow just in case there is a difference in the contrast.

Hemoglobin has a high absorption rate around 415 nm. That is why UV light is used in forensic science to check if a stain is blood (very dark) or not (somehow reflecting).

But this is totally useless for hunting. You cannot chase something that is not reflecting. Most of the plants and most grounds do not reflect UV so you will see nothing.

I have watched several videos about blood tracer flashlights but I am still not sure how good they work. Most video material is just too bad.
Looking at the reflectance (what you see) of blood (example figure) there are not a lot of wavelengths that blood is reflecting: Red, deep red and infrared.

Any light with a warm spectrum would be much better that a cold LED light. The warmer the better. Maybe assisted with some extra red and IR LEDs.
Using orange or red filters may be even better. They cut out all colors below 600 nm. Seeing less green should help in the forest.

This is about that moment I usually get that, “But I once saw in a movie…” response. Haha.

Honestly, I have found that following blood trails is a skill like any other when it comes to hunting…you just have to develop it over time and with practice. You start out slowly, checking every step carefully, but after awhile you know what to look for and it comes more easily. You also start to understand the way animals move when mortally wounded and can anticipate where to look.

But yeah, it would be cool to have a light that made it glow like Predator blood.

LED blood tracker lights work fine - reds/oranges really pop out, but since these use both red and blue LEDs running together, blues also pop out (not normally a problem when hunting as blue is rarely encountered).

An incandescent light with a blue filter doesn’t pop red/orange colors as much but it does not pop blues and better isolates red/orange from other colors. Red and orange filters do not work at all.

So we know a lot that is not working. But how do these lights work? Just red and blue LEDs?

I don’t know the physics behind all of this, I have just done some very quick and simple tests to see what works and what doesn’t.

I would guess that the reason blue filters work on incandescent lights and not LEDs might have something to do with infrared. Incandescents put out a good amount of IR and LEDs hardly any.

Why a combination of blue (or green) and red LEDs are needed to work I do not know. But I do notice with LEDs red actually looks more orange than red. Apparently single LEDs can be used if they put out the right mix of blue and red light – the Bushnell tracker light that I have has 3 tracking LEDs that all appear to be the same magenta color, most others seem to use a combination of red and blue LEDs.

I added a video test to the OP.

Nice video. How do you come up with these ideas and the time. Anyways it appears the blue/green was the best. But I probably won’t have one of those with me if ever in that situation but I will have a WW high CRI. Thanks for putting that together.

Nice test Vestureofblood! This is unique test to bust all kind of flashlight blood tracking sellers that are selling real “myth” for costumers believing that red, blue, green light does make difference while their only function is to blind you while tracing for blood trail.

If someone finds/invents flashlight that really works with blood trail it will be big hit in hunting world cause every hunter wants one in a backpack.

Until that light appears I will just stick to cool white zoomie which works the best of everything I seen or tried till now.

P.S. It gotta be zoomie? Why?
Zoomie light without any spill unlike the reflector light has very sharp borders, so there is better contrast between illuminated area and dark area. The enhanced contrast lets you perceive blood trail better and you have preserved night vision.