Trang chủ » blog » Fingerprint powder – Wikipedia

Fingerprint powder – Wikipedia

Fingerprint powders are ticket powders used, in conjunction with fingermark brushes, by crime view investigators and other law enforcement personnel to search for and enhance latent/invisible fingerprints that can be used to determine identification. [ 1 ] [ 2 ] This method acting of fingermark development normally referred to as dusting for fingerprints, involves the attachment of the powder particles to the moisture and perspiration secretions deposited on to surfaces by the raised ridges on fingers, palms, or soles of feet designed for fascinate, called friction ridges. [ 1 ] [ 2 ] [ 3 ] Physical development of fingerprints using powders is one of many methods that can be employed to enhance fingerprints ; it is typically used to search for fingerprints on big non-porous surfaces that can not be submitted for chemical development within a lab. [ 3 ] however, this particular method acting is best suited for the enhancement of newly deposited fingerprints because the attachment of the powder is diminished when the impression remainder has dried. [ 3 ] fingerprint powders are normally used because of the versatility associated with this proficiency ; there is a big choice of fingerprint powderize compositions that have evolved, over clock time, to enable the safe and effective use of fingerprint powders on a across-the-board range of backgrounds. [ 3 ] [ 4 ] [ 5 ] Fingerprint Developed Using Magnetic Powder with a Scale

writing [edit ]

In general, two components are present in dry non-magnetic fingerprint powders : a color, typically inorganic in nature, and a material for attachment within the powder such as stearic acid, cornstarch or Lycopodium powder, the spores of the Lycopodium and early associate plants. [ 3 ] [ 6 ] In addition, a filler material such as interlock pumice is frequently added to keep the color and attachment material together while preventing the formation of big clumps within the gunpowder that would result in ineffective application onto the surface. [ 3 ] however, modern fingerprint powders are ample and include both dry and aqueous options. [ 3 ] The dry fingerprint powders are frequently categorized into six basic types based on the general composition ; however, some powders may belong to more than a one group. [ 3 ] [ 4 ] These dry powders can be added to a dilute detergent solution that can be applied to surfaces to develop fingerprints. [ 3 ]

peel off powders [edit ]

bit powders are composed of metallic particles. [ 3 ] [ 4 ] The most coarse alloy corporeal used in this type of powder is aluminum ; however, bronze, gold, copper, iron, and zinc are much used vitamin a well. [ 3 ] [ 4 ] [ 6 ] Aluminum powderize shows up on a variety of surfaces and is a particularly popular gunpowder choice in the United Kingdom. [ 4 ]

farinaceous powders [edit ]

chondritic powders were invented in the 1920s as one of the first types of fingerprint powders available. [ 3 ] [ 4 ] The materials used to make these powders were chalk, lamp black, graphite and a variety of run and mercury components. [ 3 ] [ 4 ] [ 6 ] Modern chondritic powders do not use lead or mercury because they have been known to cause health complications with elongated use. [ 3 ] [ 4 ] Black farinaceous powders, normally used in the United States of America, are now composed of carbon-based particles. [ 3 ] [ 4 ] however, a broad range of colours are besides available to provide contrast with many backgrounds. [ 3 ]

charismatic powders [edit ]

The foundation of magnetic powders is chondritic or flake powder, of any color. [ 3 ] [ 6 ] The magnetic view is attributed to the addition of small cast-iron particles. [ 3 ] [ 6 ] Magnetic powders enhance fingerprint details more effectively than traditional chondritic and flake powders because the particles are finer and the method acting of application is less invasive. [ 3 ] [ 4 ]

fluorescent powders [edit ]

fluorescent powders are available in both farinaceous and magnetic compositions. [ 3 ] The fluorescent part is provided by adding a color dye to the powder to allow for better visual image of scatter fingerprints on motley surfaces with the use of ultra-violet ( UV ) light or an alternate light reservoir ( ALS ). [ 2 ] [ 3 ] [ 4 ] [ 7 ]

Nanopowders [edit ]

Nanopowders are a relatively new type of gunpowder composed of nanoparticles. [ 3 ] [ 4 ] [ 8 ] Similar the magnetic powders, these powders provide greater ridge detail in newly deposited and aged fingerprints due to the highly small atom size. [ 4 ] [ 8 ]

Infrared powders [edit ]

Infrared powders are used in conjunction with infrared light. The features of the fingermark are distinguished from the surrounding background because the infrared light is absorbed in the fingerprint preferably than reflected. [ 3 ] These powders are most beneficial for enhancing fingerprints found on money bills in countries that use polymer currency because the powder removes issues related to the visual image of fingerprints on items with colorful, brooding and fluorescent properties. [ 3 ]

factor influencing fingerprint powderize choice [edit ]

There are several factors influencing the potency of fingerprint powders. [ 4 ]

Particle size and human body [edit ]

The powders with finer particles show greater detail within the fingerprint than powders composed of larger coarse particles.[3][5] In addition, particles with shapes that provides a larger surface area promote greater adhesion to the fingerprints.[4]

adhesion [edit ]

Effective enhancement of fingerprints relies on the adhesion of the powder to residue composing the fingerprint impression without adherence to the rest of the surface, otherwise the view of the fingerprint will be obscured.[4][5] Adhesion of the powder particles to the fingerprint residue is partially attributable to the electrostatic attraction between the two; however, the adhesion is mainly guided by the increased contact between the moisture in fingerprints and the powder, and the surface tension.[4][5]

color [edit ]

The fingerprint powder must be a suitable colour for the surface in question by providing contrast.[3][5][7] The details of fingerprints deposited on light surfaces are best visualized by applying dark or black coloured powders.[3][5][7] Conversely, white or grey powders are recommended for enhancing fingerprints found on dark surfaces.[3][5][7] However, there are also powders available that contain elements that provide contrast on all types of surfaces; these powders are advantageous at crime scenes where both light and dark surfaces require fingerprint development because the powder type/colour does not need to be changed between uses.[3] Although, multi-coloured surfaces are more complex and, therefore, fluorescent powders and additional light sources are required to provide the best contrast in these situations.[2][3][4][7]

consistency [edit ]

The powder should not clump together because the important identifying details within the fingerprint can become destroyed during the application of the powder.[3]

Powder excerpt and lotion [edit ]

In the past, powders were selected based on personal option or outlined standard procedures of the consociate department or agency. [ 4 ] however, despite this freedom in the powder survival procedure, crime scene investigators should ultimately choose powders that provide the best contrast against the surface the fingerprints are deposited on, with consideration for the characteristics of the surface itself. [ 7 ] Most fingerprint powders are applied with a fingerprint brush composed of highly ticket fibers designed to pick up powder and gently down payment it through a whirl motion onto the fingerprint to reveal it without removing the delicate remainder composing the fingerprint itself. [ 3 ] [ 7 ] There are many different types of brushes that can be used for applying fingerprint powderize ; the choice largely depends on the stage of fingerprint development. [ 7 ] For model, feather fingerprint brushes enhance contingent within fingerprints located during an initial search with fingerprint brushes composed of fiberglass fibers. [ 7 ] Fingerprint powder may be applied using aerosol methods that do not involve direct contact with the airfoil. [ 5 ] [ 7 ] charismatic powders differ slenderly from traditional powders in the manner that they are applied to fingerprints. specifically, a magnetic applicator is used in place of a fingerprint brush composed of fibers. [ 3 ] The attraction within the applicator attracts the charismatic powder forming a bunch of powder that can be gently moved across the fingermark ; once complete the attraction within the applicator is retracted and the charismatic gunpowder falls off. [ 3 ] The benefit to this lotion method acting is that no bristles touch the surface and, therefore, there is less potential to damage the print compared to other methods of developing fingerprints. [ 4 ] [ 7 ] regardless of the method acting chosen to apply fingerprint gunpowder, there must be careful consideration not to apply excessively much powder that could ruin the fine details within the fingerprint needed to make an identification. [ 7 ] In addition, fingerprints contain DNA that can be used in subsequent forensic deoxyribonucleic acid analysis and, consequently, it is important to mitigate the risks of DNA contamination when applying fingermark powderize. [ 7 ]

farther Applications/Uses [edit ]

Fingerprint powder is useful for the detection and collection of latent fingerprints, but that is not all the analysis that can be done. Kaplan-Sandquist, LeBeau, and Miller conducted a study where they tested fingerprint development methods with the MALDI/TOF MS. The fingerprint powder was found to be utilitarian as a MALDI matrix. [ 9 ] This instrument can identify many compounds. In the report, fingerprints tested contained known solvent residues. The fingerprint powderize along with the MALDI matrix had the highest average signal detection rates of ( 88 % ). [ 9 ] Since this study was controlled, it is known that the function of this far application with the MALDI/TOF MS would be effective. [ 9 ]

Associated heath concerns [edit ]

fingermark powders used in the past contained materials that were considered carcinogenic and toxic. In particular, lead and mercury components were removed from fingerprint powders due to consociate cases of mercury and lead poison. [ 3 ] [ 4 ] [ 5 ] advanced fingerprint powders pose significantly fewer health risks because they are composed chiefly of organic components ; however, there is concern that the belittled particles within the fingerprint powders may be inhaled and after prolong exposure can result in the development of lung diseases. [ 3 ] Powders with smaller particle sizes such as fluorescent powders, or the newer nanopowders are particularly concerning because they are small enough to reach and settle deep within the lungs. [ 3 ] It is, therefore, recommended that individuals frequently using these powders take the necessary precautions to mitigate the risk of respiratory illness, whether that be working within a reek hood or wearing a mask. [ 5 ]

See besides [edit ]

References [edit ]

source : https://leowiki.com
Category : Economy

Post navigation

Leave a Comment

Trả lời

Email của bạn sẽ không được hiển thị công khai.