Why IR or UV?


Why are we interested IR and UV? Perhaps it is just a slightly-away from normal means to monitor our surroundings. Perhaps it is simply a matter of easy access to the technology. Again, there is no scientific basis behind IR and UV having any relationship to the unusual events we seek to explain. Thermal imaging is within the realm of IR but will not be discussed here. The primary intent of this discussion is to illustrate the limitations of the technology we use. Research your equipment to understand exactly what it is and isn’t providing for you.

A “full spectrum” camera is not capturing a full spectrum image. With respect to the visual bandwidth, standard cameras are already “full spectrum”. The specifications of the sensor in the camera will indicate sensitivity to frequencies beyond that of human vision. Filters are added to the light path in the camera to block infrared and ultraviolet along with software interpretation of the data from the sensor to result in an image our eyes and brains recognize. What is marketed as “full spectrum” simply has the IR and UV filters removed. This allows a wider bandwidth of frequencies to reach the camera sensor. All we are actually achieving with a “full spectrum” camera is a level of enhancement to the tiny portions of the IR and UV bandwidths our eyes already perceive.

Potentially increasing the discrepancy, we tend to use LED illuminators. LEDs emit a very specific frequency. If whatever we are trying to enhance is at a different frequency, the LED illuminator may be washing out the image preventing capture of the desired image. Also, without understanding the specifications of the camera sensor, the illuminator we choose may not emit a frequency the camera can sense properly regardless of the intensity of the LEDs. Be sure to understand the light wavelength/frequency the given camera and illuminator are designed for. There are alternate non-LED illuminators but these come with heat/fire risks from IR lamps and potential eye and skin damage from UV lamps.

More effective IR and UV image systems are available but may come at significant cost. We see IR imaging every day associated with “FLIR night vision” systems and satellite/telescope imagery. UV imaging is not as prevalent in the media but we may hear mention of it related to forensics and utility troubleshooting as well as satellite /telescope imagery.

A few typical sensitivities/specifications to consider:

For perspective; 1 Hz is once per second, 1 THz is 1,000,000,000,000 times per second

Infrared bandwidth: 300 GHz to 430 THz

Ultraviolet bandwidth: 790 THz to 30,000 THz

Typical human vision sensitivity: 400 THz (red) to 790 THz (violet)

Typical unfiltered camera sensor sensitivity: 303 THz to 999 THz

-covers about 29.56% of the IR bandwidth

-covers about 0.5% of the UV bandwidth

Typical Infrared LED emission range: 316 THz to 353 THz

-about 8.6% of the IR bandwidth (best case using a wide variety of IR LEDs)

-a typical LED illuminator operates with numerous LEDs of a single type. Since each LED type emits a specific frequency, a typical IR illuminator is providing illumination equivalent to 0.0002% of the IR bandwidth or about 2% of the effective IR range of an unfiltered camera. These number are even less effective for the UV bandwidth.

Typical Ultraviolet LED emission range: 749 THz to 821 THz

-about 0.2% of the UV bandwidth (best case using a wide variety of UV LEDs)

Again, an excellent graphic showing the EM Spectrum (thanks to Sparc Para Analytics):


Professional camera conversion:


Rob Hillstrom

Rob Hillstrom

Director / Chair Science at TEPI
Paranormal: Somewhat cliché but, my experiences began at a young age though I don’t recall making the “paranormal” association until the age of 9 when my grandmother died and returned for a visit. Through the years, I have given many phenomena more attention; from subtle dream images to apparent physical contact from “unseen” sources. I have been involved in independent research/study and investigation for about 30 years and began using some equipment about 20 years ago. I have been working with the Colorado based TEPI team since 2010. As a science oriented investigator, I am a bit of a contradiction. I believe the experience more so than the evidence. Simply because there can be many plausible explanations for most evidence. The experience on the other hand, can sometimes be very complex and difficult to explain easily. Professional: I have a Master of Science degree that essentially qualifies me to manage a multi-discipline team in their efforts to accomplish technical activities. (If I say more the MIB might show up.) My engineering background is primarily electronics but includes mechanical, astrophysics, and some aspects of thermal, optical, and audio. Previous careers were medical including paramedics and medical device technology (design, manufacturing, and training medical staff). I also dabbled heavily in photography before the wide spread use of digital imaging. Ideological: I was raised Presbyterian but allowed to find my own path. I studied Zen for a short time and explored many other faiths. In my late teens I attended a seminar on the subject of Quantum Physics and how it relates to our mind and consciousness; this was the turning point in my belief system. I did not become a scientific skeptic, I simply began to view nearly everything differently. I removed definitions I had learned and replaced them with relationships to my personal experiences and observations. Things once clearly defined as paranormal now had a plausible spin to them. Personal: In my spare time I write dark music, dark poetry, and horror/science fiction stories.
Rob Hillstrom

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