Fingerprint powder is a fine powder used to clean fingerprints by crime scene investigators and others in law enforcement. The dusting process for fingerprints involves various methods intended to get the powder particles to adhere to the residue left by the ruptured friction skin on the fingers, palms, or legs.
The physical development of fingerprints using a powder is just one of the choices of methods used to develop fingerprints. Fingerprints often leave the oil residue in the form of a frictionless ridge, but the friction ridge skin itself does not remove oil, so some fingerprints will leave only amino acid residues and other compounds whose powder is not well attached. For this reason, 'dust' is used as part of various techniques to develop fingerprints, but is often used on a wider area of ​​the scene that can not be moved for analysis, or can not be a more rigorous subject of analysis for other reasons.
Fingerprint powders have various formulations, and suitable powders should be used on suitable surfaces. For example, dark-colored powder will show much better fingerprints on light surfaces.
Video Fingerprint powder
Apps
The powder can be applied with a fingerprint brush, a brush with very fine fibers designed to hold the powder, and store it gently on the fingerprint to open, without rubbing the fingerprint residue itself. They can also be applied by blowing powder on the fingerprint, or by pouring the powder into print, and then blowing the excess.
Magnetic powder is also used, where the fine magnetic powder is held by a magnetic applicator, which can then be gently moved across the fingerprint. Since there are no feathers touching the surface, this often damages the mold less than other methods to develop the mold.
Maps Fingerprint powder
Composition
Modern fingerprint powder has a variety of compositions, and is often a matter of personal choice by the expert using it or into standard department or agency procedures. Many agencies use exclusive powders produced by independent companies, and the exact formulation of these powders is not disclosed.
Some surfaces, such as organic ones, are not needed for fingerprints at all and the use of alternative methods is required. Other media, such as certain types of glue, can be "smoked" on this surface with just results.
Historically, Lycopodium powder, Lycopodium spores and related plants, are used as fingerprint powders.
Factors that affect the quality of the fingerprint powder
There are several factors that affect the effectiveness of fingerprints.
- Subtlety
- The powder should be good enough to show fingerprint details. The finer powder is theoretically capable of displaying greater detail than coarse powder.
- Adhesion
- The powder should display the right adhesion level, so it will attach to the rest of the fingerprint (often oil) and not stick to the entire surface where it will obscure the print view. When the powder coats the surface, this is known as 'painting'.
- Sensitivity
- Sensitivity is related to adhesion, and how well the powder is attached to the surface. For example, aluminum flakes are more sensitive than aluminum powder, but greater sensitivity is not always desirable.
- Color
- The fingerprint powder should be a suitable color for the intended surface.
- Stream
- For the lower levels, it is important that the powder can flow, and not the 'cake' into a solid block, which will make it useless.
Because these qualities are not usually all in one material, the composition of the various materials is commonly used. For example, soot is very black in color, absorbs about 98% of visible light incident, but other materials may have greater adhesion, or flow more effectively, produce better overall powder than just themselves.
Sample material
- Metal powder
Of this amount, one of the more commonly used powders today is the aluminum powder, as it will appear on various surfaces.
See also
- Fingerprint
- Mold gloves
External links
Source of the article : Wikipedia
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