What is a Thermal Imager?

007-3483-01_LgOne thing we all hear about in relation to paranormal research is thermal imaging. If you watch the paranormal shows it is used by all the “famous” ghost hunters but what is it and how does it work?

Before I started researching this, I thought I understood what it was and how it worked. I thought of it in the simplest terms. A thermal imager detects heat and cold, puts it up on a screen for you to see and if you see heat or cold where there shouldn’t be any you might have captured a ghost. Right? Well, according to some of what I have found in my research, this is not necessarily correct.

Like I did, most people seem to view a thermal imager as a “heat viewer”. The research I have done indicates it is more complicated than that. It is more like a camera that instead of recording visible light records mid and far infrared.

Digital cameras pick up visible wave lengths, what we see with the human eye. Thermal imagers pick up longer wavelengths ( further from the visible spectrum ). Most objects just absorb or emit these wavelengths without reflecting them. We are used to seeing objects by reflected light but the thermal imager sees them by virtue of emitted mid and far IR. The wavelength of this emitted radiation is characteristic of the temperature of the object which is why it can be used to produce a ‘thermal image’. The wavelength of the radiation is measured in an array of tiny sensors which is used to calculate an equivalent temperature for each point. This is used to build up a ‘false colour’ contour image of the scene showing the temperature of the visible surfaces.

The world looks very different through the eyes of a thermal imager. Most objects will give a temperature reading to the thermal imager. This is because they emit mid and far IR rather than reflect it. Since the image shows the temperature instead of the light reflected off of it, there can be hot and cold spots that would not show up in a regular photograph that is only portraying reflected light.An object that has previously been in contact with another object that is hot/cold can still reflect that heat/cold since heat, unlike light, moves slowly through a solid object. An example of this is a chair may still show a warm image of a human for some time after they have gotten up out of the chair when viewed with the thermal imager.

Not all surfaces show their true temperature. Some surfaces like metal, glass, polished ceramic and stone actually reflect mid and far IR rather than emit it.Any temperatures or even images on these surfaces could quite possibly be a reflection from another source. These types of reflective surfaces can even reflect radiation onto surrounding surfaces, warming them up. Reflective objects can also reflect radiation directly into the thermal imager lens causing strange false images similar to lens flare in a regular camera.

Since mid – far IR acts like light, you can still get the same type of anomalies that appear in regular light digital photographs. Strange shapes ( faces, figures, etc) can show up appearing to be paranormal in nature. Since objects appear completely different in IR than they due is regular light this can lead to false perception of images. What appears to be a tall ghostly figure on the thermal imager may in fact really be a tall metal object.

As with ordinary cameras, images in the thermal imager can be out of focus.Also, since mid and far IR has a longer wavelength that light images will always appear fuzzier than in normal light photographs. Because of this, thermal images should not be expected to produce a lot of detail.
One way to combat this is to always use a regular light camera in conjuction with a thermal imager. In this way the identity of any strange shapes that appear in the thermal imager can be verified.

Am I saying that thermal imagers are useless in detecting possible paranormal anomalies or events? Absolutely not. What I am suggestig is that the more you know about how they work and what they are actually showing the less chance you will have of being fooled by a false image. Knowledge is power and the more we know and understand about the technology we are using the better chance we have of finding and understanding those things that truly are unexplained by science as we now know it.


Sara Fawley

Sara Fawley

Hello my name is Sara Fawley. I was born and raised in San Diego, Ca Oct 1965. I lived there until I was 19, then moved with my now ex-husband to Texas where I lived for the next 25 years. I have two grown sons who are married and have lives and families of their own. My current husband and I now live in a small town in Arkansas with our dachshund Shabar. I owned and antiques and collectibles shop but closed it down in September 2013 after having a heart attack. I still buy and sell antiques and collectibles and make handmade natural gemstone jewelry which we sell at shows and festivals. I don't recall ever not knowing that there was more than just us out there. My first experience happened when I was a young child and was visited by my godfather "Grandpa Clyde" at the time of his death and for three weeks after that. I have seen one other full bodied apparition in my life and had several other minor experiences that left me scratching my head.I am not an investigator but have a huge thirst for knowledge. I am always looking up this or that legend, myth or story I hear or sometimes I just have random thoughts and look them up to see if anyone else thinks the same way. I am very analytically minded and always like to get to the bottom of things.
Sara Fawley

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