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UV Light in Forensics & Crime Scene Investigation

Updated: Jun 28, 2023

UV Light in Forensics


Forensic Lighting helps the operator see what the naked eye wouldn't usually detect or evidence that could potentially be otherwise missed at a crime scene.


Forensic investigators, Police Forces, Forensic Laboratories & researchers utilise a wide range of Labino ALS light sources to aid them in examining & finding evidence, either at a crime scene or for further analysis at a laboratory.

We at Advanced NDT LTD have been selling Labino Forensic UV Lights & Crime Kits to returning customers for a number of years, view our full Forensic Product range here.


Many biological fluids are fluorescent in nature, including sweat, saliva, blood & semen. When such traces are illuminated with light of a certain wavelength they fluoresce & are detectable to the investigator. The degree to which various substances become visible when using different filters depends on the state of the substance and the surface on which the substance exists.

Deciding what light source to use to achieve the best result in finding traces at the crime scene comes with experience - It can take years of experience to learn what light & wavelength to use depending on the occasion - it’s not an exact science.

New users using ALS (Alternative Light Sources) can of course use combinations of light and goggles to determine the best option for the evidence & scene using trial and error.


We supply differing wavelength kits, from full kits covering the entire spectrum of forensic testing to individual torches at specific wavelengths & UV LED lights, small intense & large coverage beams for all purposes - whatever your requirement, we can have it covered.


No crime scene looks the same & no crime scene investigator uses the same method.

Crime Scene

 

Detecting Blood Stains

There are several common ways to detect blood at the crime scene, although people are often misled from films & TV.. blood doesn't fluoresce in the way you would imagine!

However, one very easy and quick way to detect blood is still to use a UV light source. If there is a presence of blood, the stain will appear black under UV light at 365nm.


When to use UV light to detect blood:

• Reduce the risk of collecting unnecessary stains

• Detect blood on dark, red or violet surfaces

• Find blood stains that are concealed by paint


Reduce the risk of collecting unnecessary stains


By using ultraviolet light it's possible to do a quick but effective check for possible bloodstains. A bloodstain exposed to UV light absorbs all light of that bandwidth and does not reflect back – that is to say, it does not fluoresce in any way. Thus the stain will appear black under UV.

Although not a conclusive test for blood, it is an effective presumptive test and can often eliminate the unnecessary collection of stains that appear to be blood but are actually from another source.


Dark surfaces


The UV light source is also effective for providing sufficient contrast of bloodstains that are found on red or violet-coloured objects. Such stains often fade into the background so well that it is impossible to photograph them.

Ultraviolet light often provides sufficient contrast between the background and stain to allow the stains to be visualised in a photograph.


Blood concealed by paint

It is not uncommon that a perpetrator of a crime to try & remove potentially incriminating evidence. This may include painting over areas that have been exposed to blood.

To the naked human eye, it is next to impossible to see that a blood stain has been painted over. By using ultraviolet light however, it is possible to detect blood stains that have been concealed by paint.


Labino Crime Kits & UV Lights


Labino UVG2, UVG3 & UVG5 Head Lights - https://www.advancedndt.co.uk/labino-uvg-series-uv-led


Labino Nova Torch ALS Crime Forensic Kit
Labino Nova Torch ALS Kit




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