Diﬀ erence between conventional and modern methods for examination of ﬁ ngerprints

The impression of frictional ridges of the ﬁ nger is known as ﬁ ngerprints. Owing to this uniqueness, the ﬁ ngerprints have long been used to identify a person since Ancient times. In any crime scene the presence of ﬁ ngerprint makes the identiﬁ cation of the Culprit very easy. The ﬁ ngerprints can also easily be embedded on any item such as paper, Clothing and body of the victim. To utilize this uniqueness of ﬁ ngerprints forensic experts devised many techniques to obtain a clear ﬁ ngerprint. These come under two categories i.e. Conventional and modern methods. The conventional methods are although important but there are limitations of them. Just take the example of powder method. Powder method require diﬀ erent powders for diﬀ erent Surfaces and colors, but modern method like quantum dots method can easily detect Fingerprints on all surfaces regardless of their color giving great resolution in seconds. Other methods like physical developer method is very time consuming and expensive, carbon Black method creates mess and does not work on porous surface, iodine fuming and Naphthaloﬂ avin does have an advantage that it can bring up prints on skin also but it does not Work on metallic surfaces. VMD also fails on heavy plastic polymers and body oils. But some modern methods like nanotechnology can obtain high resolution prints old and dried prints also within 3 minutes. Laser technology is very fast, accurate and can be used for Fingerprints up toten years old also on any surface without any mess. Multimetal deposition Method can even be used to identify smokers and drug addicts and can be used Porous, non-porous and wet surfaces.


Introduction
Fingerprints are gods own seal that are given to us that we may recognize his best creation-man.

Pattern classifi cation
All inger prints can be divided into four basic types: ARCHES, LOOPS, WHORLS AND COMPOSITES. Again are further subdivided in to the following types:

Finger print developing kit
When visiting a scene of crime, inger print experts carry with them a latent print development kit consistence of variety of powders and brushes, lifting materials, magnifying glass, lash lights, two pairs of gloves, one pair of scissors, one pocket knife, one tape, ingerprinting kits and slips.

Technique preference
The technique to the used for the development of latent ingerprints depends on various factors:

Abstract
The impression of frictional ridges of the fi nger is known as fi ngerprints. Owing to this uniqueness, the fi ngerprints have long been used to identify a person since Ancient times. In any crime scene the presence of fi ngerprint makes the identifi cation of the Culprit very easy. The fi ngerprints can also easily be embedded on any item such as paper, Clothing and body of the victim. To utilize this uniqueness of fi ngerprints forensic experts devised many techniques to obtain a clear fi ngerprint. These come under two categories i.e. Conventional and modern methods.
The conventional methods are although important but there are limitations of them. Just take the example of powder method. Powder method require diff erent powders for diff erent Surfaces and colors, but modern method like quantum dots method can easily detect Fingerprints on all surfaces regardless of their color giving great resolution in seconds. Other methods like physical developer method is very time consuming and expensive, carbon Black method creates mess and does not work on porous surface, iodine fuming and Naphthalofl avin does have an advantage that it can bring up prints on skin also but it does not Work on metallic surfaces. VMD also fails on heavy plastic polymers and body oils. But some modern methods like nanotechnology can obtain high resolution prints old and dried prints also within 3 minutes. Laser technology is very fast, accurate and can be used for Fingerprints up toten years old also on any surface without any mess. Multimetal deposition Method can even be used to identify smokers and drug addicts and can be used Porous, non-porous and wet surfaces.

Basic Pattern
Sub Division Symbol

Developing a scene of crime fi ngerprints
Visual examination: crime scene is checked for latent ingerprints by using oblique light sources. Sometimes latent ingerprints are revealed if the surface is clean and smooth.
Fluorescence examination: High intensity light sources using different ilters are also useful to reveal ingerprints. On dark surfaces grey or white powder is used whereas on light surfaces black powder is used. Original single base powders like lampblack or inely ground charcoal was used on light surfaces and lead powder or cigar ash was found useful on dark surfaces. But this powder has come to be known in the recent past making use of more than one ingredient.
Black powder: Results are obtained with this powder when applied on paper and chinaware.
Grey or white powder: Excellent obtain from glassware, silver wares and pelted wares.
Red powder: Useful to develop ingerprints on paper where the prints are fresh.
Silver powder: It is used hard surfaces which are painted, polished or vanished and objects like cellophane.
Physical developer: Used for developing prints on wet surfaces because organic residues are insoluble in water so the physical developer can detect latent impression.

•
Produce dark grey or black impression. •

Used porous surfaces
• Used when nihydrin and iodine fails to work.

Disadvantages:
• Time consuming Expensive

Iodine fuming
Principle: Natural body fats and oils sebaceous material temporarily absorb the iodine vapor. This result in a change in color from clear to a dark brown until the effect fades with time IODINE FUMING is used to reveal prints on porous and semi porous surfaces such as paper, cardboard, and un inished wood but not on metallic surfaces

•
One of the earliest methods • Inexpensive

• Easy
Carbon black: • Consists of charcoal and binder.
• Applied on light color surfaces even show up on black glossy surfaces as light colored.
• Produce dark gray image

Cannot work on porous surface
Ninhydrin: • First used in 1959 • Ninhydrin used on porous surfaces like paper and wall • It reacts with free amines of lysine residue in protein sloughed off in ingerprints Produce deep purple color • Applied by spraying or dipped. Development is done in highly humid environment because water is necessary for reaction • Stored in dark place to avoid degradation Disadvantages: • Development need long time without humidity • Storage is dif icult because it is degraded after some time Specimens that have been successfully treated using VMD • The questioned surface is placed in a chamber from which the air is evacuated • The chamber also contains small pieces of gold and zinc that can be heated electrically to vaporize • Zinc cannot deposit on the oily residues present in the ingerprint but gold can deposit on the ingerprint but gold can deposit on the entire surface. Gold is absorbed into oil containing ridges of the ingerprint thus there will be no gold on the surface of the ridges https://doi.org/10.29328/journal.jfsr.1001025 Disadvantages: • Effectiveness can be reduced by the presence of body luids and drugs residues • Dif icult to develop prints on heavily plasticized polymer • Requires expensive equipment and material

Modern methods of fi ngerprint development
Quantum dots: In the last few years, another approach that has garnered a lot of attention is the use of quantum dots (QDs) for ingerprint detection. QDs are interesting because they luoresce strongly under UV light and have varying emission spectra based on their particle size. The type of QDs most studied in the context of ingerprint detection are ones that derive from cadmium, namely cadmium sulphide (CdS), cadmium selenide (CdSe), and cadmium telluride (CdTe). Focusing on CdTe, this type of QD can be made to be water-soluble, so it can be applied to the prints in an aqueous solution. It can also it can be made to luoresce at different colors based on the size of the particle. As a result, it can be an effective detecting agent on surfaces of all different colors. After be ingrained with the water-soluble CdTe for a number of minutes, the prints produced are of far higher resolution than anything that can be produced by conventional methods.
Similarly to the gold nanoparticles, these QDs can also be functionalized with a variety of chemicals. In a newer study, CdTe QDs were capped with mercaptosuccinic acid (MSA) and this resulted in a much shorter time for the image to develop. Formerly, using CdTe QDs would require approximately 15 minutes of bathing in solution to produce a visible product, but the MSA capped CdTe QDS was able to produce visible prints after a mere second with a greater resolution than the best chemical print developers currently used.

Nano technology method:
The technique makes use of the facts that antibody Nano particle conjugates can be synthesized to target amino acids which are present in ingerprints. Amino acids in sweat on non-porous surfaces are targeted by ANTI COTININE antibodies that bind to amino acids when the antibodies bound to the amino acids the Nanoparticles resolve the molecular compounds leading to a much clearer ingerprints picture. Antibodies are purpose built devises with distinct functional domains. Native antibodies are comprised of four polypeptide chains two heavy chains and two light chains joined by interchanging disulphide linkage.
Traditional gold solution is replaced with more stable equivalent wherein the gold Nanoparticles bristle with long hydrocarbon chains and are suspended in petrol ether.
They stick to the ingerprints residues through hydrophobic interactions and can be developed with silver producing high quality prints after just three minutes immersion time. but gold being unsuitable, it is stabilized by n alkanethiols. Enantio selective ANTI L AMIMO ACID antibodies conjugated to gold Nana particles are found to facilitate the detection of latent ingerprints by interacting with amino acids present in friction ridges secretions .this antibodies based and dried ingerprints on non-porous surfaces.
Iodine and a naphto lavon method for skin: Finger print on skin can be detected by the use of iodine and a naphthalene .iodine reacts with greases and oils left on surfaces from ingerprint .iodine fumes are generated using a standard iodine fuming pipe and directed on to skin through a funnel, approximately 30 seconds exposure provides suf icient iodine fuming to see the brownish outline of the ingerprint. The iodine also reacts with the background skin but allowing it to evaporate for several seconds improves the contrast. The naphtho lavone is dissolved in a chloroform cyclo hexane solution and is applied to the area in the foam of an aerosol spray application when the naphtho lavane reacts with the iodine a dark blue color chemical is produced which is easily seen against the skin.

Multi metal deposition
Currently, there are a multitude of techniques which police utilize in detecting latent ingerprints, including optical methods, physical methods (such as dusting), and Chemical methods: While these methods are effective, there is still much room for improvement. The irst technique that uses nanoparticles for ingerprint detection is called multi-metal deposition (MMD) and involves a two-step chemical process. First, an object would be placed in an acid bath containing gold nanoparticles, in which the gold attaches itself to the ridges of the inger print left on the object. Next, the object is soaked in a bath of silver nanoparticles, where the gold layer acts as a nucleation site for the silver to build onto, thus forming a visible print. This technique can be augmented by the addition of functional groups onto the gold particles. One interesting example was created in which a speci ic antibody that is related to nicotine is attached onto the gold nanoparticles. During experimentation, the solution could not only effectively reveal ingerprints, but the ingerprints themselves would also luoresce under UV light if the donator of the prints was a smoker. While this study focused speci ically on smoking, there is no reason to think that this technique could not be adapted to incorporate other indicators for a variety of drugs or other sweat-secreted chemicals.
MMD is a highly versatile technique because it has been shown to be effective on both porous and non-porous surfaces as well as surfaces that are wet. However, it is limited by the fact that it requires the object with the ingerprints on it to be bathed in an aqueous solution of the gold nanoparticles. It is thus not useful for inding prints on surfaces such as walls or loors at the scene of the crime or for any object too large to be soaked in a desk top bath. Another technique that scientists are testing involves improving the conventional method of applying a ine dust to the site and then brushing away excess, leaving only the particles that adhere to the ridges of the print.
Scientists are now experimenting with dust that has nano-scale particles rather than the classical micron-range sized particles. These studies have shown that when gold is used as the metal for the nanoparticles, nano-dusting has been able to produce higher resolution prints on a variety of surfaces. Having high resolution prints is important because the detail of a print is very ine, and slight imperfections can dramatically affect the ability of the police to use them in an investigation. This is especially true in the case of partial prints, when only a portion of the ingerprint is found. Tests with other types of nanoparticles such as zinc oxide and iron oxide have also been successful at producing high resolution prints through dusting. The zinc oxide was shown to be able to effectively lift prints on non-porous surfaces even when the prints have been aged for longer than a month. Tests have also been conducted on titanium dioxide particles and have revealed that it generally has the same effectiveness as conventional dusting methods. Interestingly, this method is very good for lifting prints off of the sticky side of tape when dissolved in a solution of methanol.

Laser method of fi ngerprint development
Laser an acronym for light ampli ied stimulated emission of radiation has become in valuable tool in the hands of forensic scientist. They are extensively used in forensic examination of ibers, paint, documents, fractured glass etc. Laser is now used for developing of latent ingerprints too. Some of state inger print bureaus like Haryana, Tamil Nadu and New Delhi using laser equipment.
If inherent luminance fails to detect latent ingerprints through laser then the same can be treated with luorescent material like COUMARIN -6 to give induced luminescence to latent ingerprints very old prints even as old as 10 years can be developed using laser method on surfaces like plastic, rubber, painted walls wood, lather.
The main advantage of laser beam over the conventional ingerprints development methods is its capability to develop latent prints that cannot be developed by any other method. Id it is highly sensitive method and does not suffer from any time limitation. The developed ingerprints show off markedly under laser source. This method is highly evolved and can become the method of choice to be followed by other conventional methods. Through the equipment is expensive it is best nondestructive method.

Conclusion
Difference between conventional methods and modern methods for developing ingerprints In conventional methods there is some draw backs suppose if we talk about powder methods there is problem how to select different color powders according to surface, if we take modern methods like quantum dots method we can use any surfaces to develop ingerprints there is no selection of powders according to surface. in physical developer it take more time to develop if we take Nano technology method clear print can develop by three minutes, conventional method like carbon black method it will create mess on developed ingerprint it is dif icult to see developed latent ingerprints.
Nano technology methods Highly used for porous, nonporous and wet surfaces by using Nano technology method we can examine latent ingerprints on different surfaces if we take modern method like multi metal deposition method the advantage of multi metal deposition method is it can analyses the ingerprint donor is smoker or not, and multi metal deposition method have capable to analyze the ingerprint donor is drug addict or not, suppose if we take conventional method VMD it cannot analyses latent inger prints on plastic polymer if we take modern method.
LASER it can analyze 10 years old prints also and can examine ingerprints on plastic, rubber, pain walls leather etc. The main advantage of LASER method is it will develop latent ingerprints very accurate manner no conventional method cannot develop latent ingerprints like LASER method .Day by day technology was increasing and changing, and crimes also increasing, for examination of latent ingerprints modern methods are best to get latent ingerprints very accurate manner with in less time .But new methods also having drawbacks, but compare to conventional method modern methods is best in all the ways.