Iodine Fuming.

Slides:

Advertisements

Similar presentations

September 10, 2014 FINGERPRINTS DAY 2: RIDGE CLASSIFICATION AND LIFTING PRINTS.

Advertisements

Developing Prints bsapp.com. Fingerprints Visible prints are made after coming in contact with colored material such as blood, paint, grease, or ink.

Methods of Detecting Fingerprints. 2 Types of Crime-Scene Prints 1. Visible Print- A fingerprint made when the finger deposits a visible material such.

“Regrets are as personal as fingerprints.” - Margaret C. Banning.

Unit 4: Fingerprints 4.5 Collecting Prints. Kendall/Hunt Publishing Company 2 Developing Latent Prints  Developing a print requires substances that interact.

Fingerprints Part II.

Why Fingerprints?  Fingerprints are the most recognizable physical evidence for the general public.  When clear fingerprints are found at a crime scene.

Kendall/Hunt Publishing Company

The patterns of friction ridges contain rows of sweat pores that allow sweat and or oil to exit from glands. Sweat mixed with other body oils and dirt.

Development and Collection of Prints. Patent Prints What would you do if you found this on the wall of a crime scene? 1.Photograph: a)With scale (ruler)

15-1 Fingerprinting Chapter 15 Crystal Violet Red Fluorescent Inked Courtesy of C. Fanning.

Fingerprint Detection and Processing Fingerprint 2.

Forensic Science Unit 3 Part 3 T. Trimpe 2007

Plastic and Visible Too.

Chapter 6.  First known use: nearly 4000 years as signatures on clay tablets.

Types of Crime Scene Prints. Three Types: Patent Prints Plastic Prints Latent (Invisible) Prints.

Fingerprinting Part II.

Latent Prints Forensic Science.

T. Trimpe Types of Prints Visible prints are made when fingers touch a surface after the ridges have been in contact with.

 Visible prints are made when fingers touch a surface after toughing a colored substance like blood, ink, grease, paint, ect.  Plastic Prints  Are.

Forensic Science T. Trimpe 2007

Forensic Science T. Trimpe 2007

Advanced Techniques for Developing Latent Fingerprints

Latent Prints Forensic Science T. Trimpe

Latent Prints Forensic Science T. Trimpe

Latent Prints Forensic Science T. Trimpe

Latent Prints Forensic Science T. Trimpe

TYPES OF FINGERPRINTS AND FINGERPRINT COLLECTION

Advanced Techniques for Developing Latent Fingerprints

Latent Prints Forensic Science.

Latent Prints Forensic Science.

Latent Prints CSI Holly Academy T. Trimpe

Chemical Developing of Latent Prints

Types of Prints Forensic Science

Latent Prints Forensic Science T. Trimpe

Latent Prints Forensic Science.

Latent Fingerprint Recovery and Amplification

Latent Prints Forensic Science T. Trimpe

Latent Prints Forensic Science.

Collecting Fingerprints

Fingerprinting Techniques

Help on the Test.

Latent Prints Forensic Science T. Trimpe

Fingerprint Lifting.

Latent Prints Forensic Science.

Latent Prints Forensic Science T. Trimpe

Latent Prints Forensic Science

Developing Prints bsapp.com.

Latent Prints Forensic Science T. Trimpe

Methods for Taking Fingerprints

Classification of Fingerprints

Latent Prints Forensic Science T. Trimpe

Methods of Detecting fingerprints

Latent Prints Forensic Science T. Trimpe

Methods for Taking Fingerprints

Latent Prints Forensic Science T. Trimpe

Latent Prints Forensic Science T. Trimpe

Latent Prints Forensic Science T. Trimpe

Dusting for Latent Prints Forensic Science.

Latent Prints Forensic Science T. Trimpe

Processing and Recovery of Fingerprint Evidence

Latent Prints Forensic Science T. Trimpe

Latent Prints Forensic Science T. Trimpe

Latent Prints Forensic Science T. Trimpe

Latent Prints Forensic Science T. Trimpe

Latent Prints Forensic Science T. Trimpe

Fingerprints: Methods of Detection

Developing Prints bsapp.com.

Fingerprint Lifting.

Presentation transcript:

Iodine Fuming

Iodine Fuming Used when latent prints need to be developed on porous surfaces such as paper.

In iodine fuming, natural body fats and oils in sebaceous material of a latent print temporarily absorb the iodine vapors. There is a chemical reaction…

This results in a change in color, from clear to a dark brown, until the effect fades with time. The color change can be made permanent by the application of certain materials, but the developed latent can usually be photographed at the greatest intensity of color change and then allowed to fade.

Suspend sample in beaker with paperclip and rubber band containing 1 g of iodine crystals and cover glass Petri dish. Heat the iodine crystals slowly and gently over candle to about 50 ºC with a heating device. Observe the development of the prints and when enough contrast has been obtained between the fingerprint and the background, remove the sample from the heat source, but keep them covered with the Petri dish. Remove from the beaker and quickly step back. Observe the prints. Record how long it takes the prints to fade.

Answer the questions on the lab handout COMPLETELY individually (you may refer to the PowerPoint): 1. How does iodine fuming “work” (what causes the color change)? 2. Is the reaction that occurs a chemical or physical change? 3. On what type of substances is iodine fuming used? 5. What are some advantages of using iodine fuming? 6. How are iodine prints made permanent? Answer the “General” questions (#6-7) on the lab sheet as well on the same paper

Look in your book pgs 64-67… When to use each type of fuming technique… Iodine fuming – porous substances such as paper, cardboard, wood…. In iodine fuming, natural body fats and oils in sebaceous material Ninhydrin – same as above react with amino acids. First used in 1954. Cyanoacrylate – (superglue) - any smooth surface i.e. glass, plastic, vinyl – but crime scene investigators are trying to get techs to use this for everything because it produces a more permanent type of print.

http://www.youtube.com/watch?v=LhwGE-w9NFs http://store.sirchie.com/Latent-Print-Dev-Iodine-Fuming-C424.aspx