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| fingerprint on hard surface |
- Techniques and Chemicals used to develop prints on nonabsorbent, porous, hard, and smooth surfaces
Dusting for fingerprints can reveal the hidden information about the identity of a suspect ,victim , and witness. In addition, dusting for fingerprints on nonabsorbent, porous, hard, and smooth surfaces can be used to verify records and create a link between the suspect and the victim of a crime. There is a specific procedure of how to collect prints off nonabsorbent, porous, hard, and smooth surfaces. The first step is examining where you want your fingerprint to be on the surface area. The second step is creating a fingerprint impression on the surface by taking oil from your nose and inserting it on the surface. When the fingerprint touches a smooth surface, it creates friction as it releases the oil between the ridges and the print that is on the on the surface. The third step is taking a small amount of powder and pour it on a piece of paper. Remember forensic scientist students that you need to take a powder that does not have the same color has the surface to dust your fingerprints. The fourth step is to shake the brush and dip it into the particular powder but tap the brush gently so there will not be a lot of excess powder. The fifth step is brushing the powdered surface of the fingerprint impression in slow strokes. The sixth step is taking cellophane tape and placing on the sample of the fingerprint. This is excellent procedure to go by as forensic scientist students when dusting fingerprints on nonabsorbent, porous, hard, and smooth surfaces.
In latent print processing, certain powders are used on are used such as black powders, silver powders, and magnetic powders. Black powders are used on light colored surfaces in order to see where to collect the fingerprint. Silver powders are used on metal surfaces, dark surfaces, and glass objects to dust. The magnetic powder is used for dusting fingerprints on wood, zip lock bags, aluminum, and metal cans. Now on soft and porous surfaces there chemical that is used called Iodine fuming. Iodine Fuming is iodine crystals are placed in a cabinet then is heated and iodine vapors are released. The iodine vapors combine with oil prints the print starts to become visible. On soft and porous surfaces such as cloth and paper are visible to the naked eye by using chemicals. The chemicals such as Ninhydrin . Ninhydrin reacts with amino acids to reveal a color of purple or pink. I love those colors. Another example of a chemical that can be used is Silver nitrate. Silver nitrate is a least toxic way of developing prints. Then the silver nitrate is mixed with distilled water and applied to paper. The paper is exposed to light. Then the prints will start to turn black.
In my personal opinion, I did not know there were so many specific powders used on specific surfaces. I thought you would just lay a print down and brush with some white powder. Now I realize that u have to be very specific in dusting for fingerprints. The powders consist of magnetic, silver, and black. I think dusting for fingerprints are to hard do because of trying to dust the print off the surface. It is unique how they have specific steps in order to collect the fingerprints off the surface. I think learning about the different powders in procedures used in dusting will help me dust fingerprints off anything in the future in case like if my little sister stole something from me.
Citations
Contributor, An EHow. "How to Dust for Fingerprints | EHow.com." EHow | How to Videos, Articles & More - Discover the Expert in You. | EHow.com. Web. 04 Dec. 2011. <http://www.ehow.com/how_2074683_dust-fingerprints.html>.
This website above gets the credibility of the idea about the procedures of dusting prints on particular surfaces.
"Types of Fingerprinting." Fingerprinting. Web. 2 Dec. 2011. <http://www.fingerprinting.com/types-of-fingerprints.php>.
This website above gets the credibility of the idea about the different powders that are used on various surfaces.
Citations for pictures "Photo: Dusting for Fingerprints © Scol22 #13797998." Royalty Free Stock Photos at Fotolia.com. Web. 04 Dec. 2011. <http://us.fotolia.com/id/13797998>.
This picture gets the credibility of the visual image of dusting fingerprints.
- Links
http://www.chymist.com/FINGERPRINTING.pdf
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