Fingerprint Development by Bla...

Fingerprints are the most commonly used forensic evidence all over the world and can be recovered in multiple ways according to the surface they are present on.

Some of the approaches are more traditional and some are more advanced and technology-based.

If someone left prints behind, there is probably a way to find these fingerprints.

Every day we touch things such as a coffee cup, a door or computer keyboards, and mobile devices. Each time we do, it’s like we leave behind our fingerprints which are like our unique signature.

No two people have the exact same fingerprints. Even identical twins with indistinguishable DNA have different fingerprints.

This uniqueness allows fingerprints to be used in all sorts of ways including background checks, biometrics, mass disaster identification, and in criminal situations.

Fingerprint analysis has been used to identify suspects and solve crimes for more than 100 years and it remains an extremely valuable tool for law enforcement. 

One of the most important uses of fingerprints is to help investigators to link one crime scene to another involving the same person. 

 There are various methods of fingerprint collection such as physical and chemical methods. Today in this article, we will see one of the most frequently used physical methods of fingerprint development, the Black Powder Method.  

History of Fingerprint Powders

Fingerprint powders have been used since the last decade of the nineteenth century.

The inventor of the finger-print classification formula, Sir Edward Richard Henry (1850-1931), advised the use of mercury-based and graphite-based powders.

The previous formulation, known as Hydrargyrum Cum Creta, had one part mercury and two parts chalk by weight. The powder was good for developing latent prints on non-absorbent surfaces like glass and dark-painted or lacquered tools.

However, the formulation was removed in 1967 due to the possibility that the mercury content posed a health risk.

Furthermore, because mercury interacted with gold and damaged its surface, it was inefficient for producing prints on gold jewelry.

For producing impressions on silver-painted items, the graphite-based power was extremely useful. However, even this powder was withdrawn since it was messy to use, especially if the examination was to be done in the open with a strong wind.

Well, this was significant from history that till now that black powders are the most significant and frequently used method for fingerprint development during the crime scene processing.

The reason is its cost-effectiveness, wide availability, and suitability in all kinds of surfaces such as porous, semi-porous, and nonporous surfaces.

Composition of Black Fingerprint Powder

Due to its color, the black fingerprint powder can be used in all light colored surfaces to provide greater contrast and visibility of fingerprint ridges on the surface after development.

Graphite, charcoal, lampblack, photocopier toners, and anthracene are all common constituents used in black powder.

These black powders can also contain a variety of different chemicals. And as per their composition, there are a variety of black powders which are being used for fingerprint development. 

• Dactyl Black: Graphite, lampblack, and gum acacia are used to create Dactyl black.
• Haddonite Black:  Haddonite black is similar to dactyl black, except that instead of gum acacia, powdered acacia is used in the formulation of Haddonite Black Powder. 
• Dragon's Blood: Dragon's blood is a black powder made from the powdered resin of the Daemonorops Draco plant.

Developing Latent Fingerprints With Black Powder

Wear the gloves in hand and locate the fingerprint on the surface by using different light sources.

All the powders described above can be applied to the surface suspected of bearing the prints as per the nature and color of the background surface.

It is done by simply loading the brush with a specific powder. Camel hairbrush is the best choice of all fingerprint experts for development by black powder.

Fiberglass brushes are also being suitably used to get the purpose achieved.

Now dusting of fingerprint powder is to be done to the area suspected for fingerprint by simple and gentle tapping or by simply twirling the brush by rotating back and forth (in a clockwise and counterclockwise manner).

This causes the bristles of the brush to flare out by following the ridge outlines which makes the powder to get deposited there and makes the latent impression visible.

Once dusting of powder is done it should be gently blown off to remove the excess powder from the surface so that a clean and clear print can be observed.

Lifting of Fingerprints

The next step is to lift the fingerprint from the surface for which you can use a clean and clear piece of transparent tape.

Put the sticky side of the tape on the surface where the fingerprint got developed by leaving at least 1 cm distance from the fingerprint area and then stick the whole piece of tape on the developed fingerprint.

The size of the tape must be larger as compared with the size of the fingerprint.

After that, the tape should be lifted from the surface and now what you have to do is to paste this tape which has fingerprint ridges on its sticky side on another clean piece of paper or fingerprint card.

Now, this is ready for level 1 and lever 2 analysis of fingerprint patterns.

Fingerprint Powder Safety Precautions

• The person who is developing the fingerprint must always put on gloves on his/her hand to avoid contamination with their own fingerprint.
  
• The area where fingerprints are present must be handled with care so that the prints do not get smudged or damaged due to mishandling.
• The powder should be applied in an appropriate quantity as the excess powder can turn out into the messy and unidentifiable print.
• The brush shouldn’t be impacted hardly on the surface as its edges can destroy the print or can add some additional lines made by the bristle of the fingerprint brush which may simulate as a ridge in the fingerprint and can misinterpret the finding.
• Photography should be accompanied at each step for records and also for the analysis as well.

Summary

Black Powder is the most basic and widely used method for developing latent fingerprints.

It's also the most time-tested method employed by fingerprint experts. It does not necessitate any specialized equipment.

Brushing and tapping can help even a novice person to generate the prints. 

Above all, powder compositions can be tweaked to fit the needs of the situation. As a result, powders with a wide range of particulate sizes, colors, and compositions can be made that are cost-effective, non-toxic, or luminous.