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For porous surfaces, scientists sprinkle chemicals such as ninhydrin over the prints and then take photographs of the developing fingerprints. For non-porous smooth surfaces, experts use powder-and-brush techniques, followed by lifting tape. For rough surfaces, the same powdering process is used, but instead of using regular lifting tape for ...

DFO (1,2-diazafluoren-9-one) is another chemical used to locate latent fingerprints on porous surfaces; it causes fingerprints to fluoresce, or glow, when they are illuminated by blue-green light. Paper treated with ninhydrin reagent reveals latent prints after being processed with a household steam iron. (Courtesy of NFSTC)

factors are physical contact from another surface, water, humidity, and temperature. 7.1.3 Surface Types. Correctly identifying the type of surface expected to bear . a fingerprint is an important step toward successful devel-opment. Surfaces are generally separated into two classes: porous and nonporous. This separation is required to select

The type of surface being searched for fingerprints often determines the technique employed by investigators. Id. at 950. Nonporous Surfaces: ... Porous Surfaces: The powder technique is not as effective on porous surfaces such as fabric, unfinished wood, and paper. Instead, investigators often use chemical methods to locate the print such as ...

latent fingermarks on different surfaces. Areas to be covered in this talk will include: a general approach to fingerprint detection and enhancement; the importance of optical techniques and specialised light sources; the types of fingerprint evidence that may be encountered; the detection of fingerprints on porous surfaces;

glossy paper. The non-porous surfaces are immersed in water for a period of 96hrs and the other set of nonporous surfaces are kept in freezer at -50 degrees Celsius. The results conclude that SPR with Rhodamine B is a best technique of development of latent fingerprints on multicolored non-porous surfaces (Figure 12).

Porous Surfaces Crime Scene Investigators often use chemical methods to locate the print such as iodine fuming, silver nitrate, or ninhydrin. When one of these chemicals comes into contact with the chemicals present in the fingerprint residue (natural oils, fats), the print become visual .

Amido Black is a protein dye stain that can be used on nonporous and some porous surfaces to enhance bloodstained fingerprints and footwear impressions. Specifically, this stain is a disulfonic acid that reacts with the lysine, arginine, and histidine pendant groups of a hemoglobin molecule (Marchant & Tague, 2007).

Laboratory testing of fingerprints on porous surfaces: Porous items are chemically treated to develop the prints. Prints can then be run through databases for matches and/or compared to known prints. Source: Crime Scene and Evidence Collection Handbook. Bureau of Alcohol, Tobacco, Firearms and Explosives, 2005.

The Surface dictates the treatment; Non-Porous Surfaces allow treatment by contact with the fingerprint material itself, Porous Surfaces require the treatment penetrate the surface to go after the fingerprint material that has been absorbed by the surface. Examples of Non-Porous Surfaces are glass, plastics, metals, and finished woods. Surfaces ...

It can be porous and non porous. Porous surfaces are absorbent. Eg – paper, cardboard, wood, and other forms of cellulose. Whereas non porous surfaces do not absorb. Eg – glass, metal, plastics, lacquered or painted wood, and rubber. Fingerprints present on non porous are more susceptible to damage. Condition of the substrate.

Since it was first used for developing latent fingerprints in 1954, ninhydrin has become the most common method used to reveal prints on porous surfaces. Nearly all forensics labs use ninhydrin for this purpose, and some seldom use anything other than ninhydrin. Ninhydrin is cheap, sensitive, and commercially available in disposable spray cans. The developed prints are a high-contrast purple ...

ii. Chemical Developers: Porous surfaces such as paper are typically processed with chemicals, including ninhydrin and physical developer, to reveal latent fingerprints.These chemicals react with specific components of latent print residue, such as amino acids and inorganic salts. Ninhydrin causes prints to turn a purple colour, which makes them easily photographed.

For all non-porous surfaces, this is perhaps the most widely used technique for developing latent fingerprints in high quality. It is a well-established method that provides strong contrast and good stability, making it an ideal basis for further digital processing in FIVE. ... The first image shows the surface bearing the fingerprint. The ...

These surfaces can be wet or moist due to various reasons, such as; washroom surface, rain, canal, or sea water. Different chemicals can be used to detect and analyse latent, non-visible fingerprints. For instance, specific powders (such as, magnetic, or fluorescent powders) are put to the exhibit’s surface and adhere to the trace’s contents.

Porous Surfaces – These types of ... When fingerprints are left on surfaces covered with blood, they are usually visible before processing and need to be photographed with special lighting techniques before any further processing. Probability of getting usable prints: High. Latent Print Overview - 2011 ...

Latent prints can be found on a variety of surfaces; however, they are not readily visible and detection often requires the use of fingerprint powders, chemical reagents or alternate light sources. Generally speaking, the smoother and less porous a surface is, the greater the potential that any latent prints present can be found and developed.

The oldest method for the recovery of latent prints involves the use of fingerprint powder on non-porous surfaces. A fine powder is used to coat the surface of the print and the impression can be photographed or lifted with tape and preserved as evidence. Another common technique used on non-porous surfaces is cyanoacrylate (super-glue) fuming.

Non-Porous Surfaces – These types of surfaces do not absorb the sweat. The fingerprint deposits can remain on the surface for a very long time (until degradation). · Examples: Glass, certain type plastics, polythene bags, metal surfaces, glazed ceramics, glossy paints, etc. · Probability of getting usable prints: High.