The papillary ridges on the tips of the fingers and thumbs leave a fingerprint impression. Because the ridge arrangement on each human finger is unique and does not change with growth or age, fingerprints provide an ironclad form of personal identification. Fingerprints can indicate a person’s genuine identity despite personal denial, assumed identities or changes in personal appearance caused by age, disease, plastic surgery, or accident. The use of fingerprints as a technique of identification, known as dactyloscopy, is a vital tool for modern law enforcement.
A double row of peg-like protuberances, or papillae, anchors each ridge of the epidermis (outer skin) to the dermis (inner skin). Injury to the ridge structure or the dermal papillae, such as superficial burns, abrasions, or cuts, has no effect on the ridge structure or the dermal papillae, and any new skin that grows duplicates the original pattern.
Identification can be made with any ridged part of the hand or foot. Finger impressions, on the other hand, are favored over those obtained from other areas of the body because they can be taken quickly and easily, and the ridges in such impressions generate patterns that can be easily sorted into groups for filing.
Where Fingerprints are found
Fingerprints can be discovered on almost any solid surface, even the human body. Analysts divide fingerprints into three groups based on the type of surface on which they are discovered and whether or not they are visible: Fingerprints on soft surfaces (such as soap, wax, wet paint, fresh caulk, and so on) are most likely three-dimensional plastic prints, whereas those on hard surfaces are either patent (visible) or latent (invisible). When blood, dirt, ink, or paint is transferred from a finger or thumb to a surface, visible prints are generated.
When the body’s natural oils and sweat are transferred onto another surface, latent prints are generated. Latent prints can be discovered on a variety of surfaces, but they aren’t always visible, necessitating the use of fingerprint powders, chemical reagents, or other light sources to detect them.
Collection of Fingerprints
Patent prints
The usual method of photography is used to collect patent prints. Using a forensic measurement scale, the prints are captured in high quality. Low light or different light sources, chemicals, dyes, and other techniques can all help to improve image quality.
Latent prints
By dusting a flat surface with fingerprint powder (such as black granular, aluminium flake, or black magnetic), latent prints can be collected. If prints appear after dusting the powder, they are photographed with a camera and then peeled off the surface with adhesive tape. To preserve the tape, it might be kept on a latent lift card. However, applying fingerprint powder can sometimes contaminate the fingerprint, making further examination impossible. Before applying the fingerprint powder, employ an alternate light source or super glue as an alternative to latent prints.
Alternate light sources
For investigating surfaces such as doors, doorknobs, and windows, investigators are beginning to employ a different light source. Typically, a laser or LED light emitting light at a specific wavelength is utilized. For shooting or additional processing, these devices may also contain multiple filters that offer distinct spectra.
Cyanoacrylate
Before applying powders or colour stains, cyanoacrylate or super glue is frequently utilised on the surface. The object is exposed to cyanoacrylate vapours while this process is performed on a non-porous surface. These vapours adhere to any prints that are present, making them visible.
Chemical Developers
Chemicals like ninhydrin and physical development can be used to probe porous surfaces and expose latent fingerprints. The chemical reacts with the elements of fingerprint remnants, turning them purple and making them visible.
The Fingerprint Analysis Process
ANALYSIS: – Analyzing a print to see if it may be utilised for a comparison is what analysis is all about. The inspection stops and the print is reported as not suitable if the print is not acceptable for comparison due to insufficient quality or amount of characteristics. Physical features such as recurves, deltas, wrinkles, and scars may also be discovered during the analysis, indicating where to begin the comparison.
COMPARISONS: – An analyst performs the comparisons by comparing the known and questionable prints side by side. To see if the minutiae qualities and places match, the analyst compares them. Known prints are frequently obtained from persons of interest, victims, witnesses, or by searching one or more fingerprint databases, such as the FBI’s Integrated Automated Fingerprint Identification System (IAFIS).
EVALUATION: – The examiner’s final decision on whether the prints are from the same source (identification or individualization), separate sources (exclusion), or inconclusive is called evaluation. Poor quality samples, a lack of comparable areas, or an inadequate number of corresponding or contrasting traits may all contribute to inconclusive results.
Verification: – It occurs when a second examiner examines, compares, and evaluates the prints independently to confirm or dispute the initial examiner’s conclusions. The examiner may also check the accuracy of the conclusions reached during the analysis phase.
Fingerprints can be utilised in a variety of applications, including
1.Providing biometric security is important (for example, to control access to secure areas or systems)
2.Amnesia victims and the unidentified dead are being identified (such as victims of major disasters, if their fingerprints are on file)
3.Background investigations are being carried out (including applications for government employment, defence security clearance, concealed weapon permits, etc.).
CONCLUSION
Human fingerprints are precise, nearly unique, difficult to modify, and long-lasting, making them ideal for use as long-term markers of human identification. They may be used by law enforcement or other authorities to track down people who want to keep their identities hidden or who are incapacitated and hence unable to identify themselves.
Academics, judges, and the media have questioned their use as evidence. Academics have stated that the mistake rate in matching fingerprints has not been sufficiently investigated and that fingerprint evidence lacks a reliable statistical foundation because there are no standardized criteria for point-counting methodologies. Experts were tested to see if they could objectively focus on feature information in fingerprints without being misled by irrelevant data.