TYPES OF FINGERPRINTS AND FINGERPRINT COLLECTION
Types of fingerprints Latent fingerprints Visible fingerprints (patent fingerprints) Plastic fingerprints (impressed fingerprints)
Latent Fingerprints (invisible prints) Invisible prints that are left on a hard surface Are formed when sweat and oil from the body is left behind on an object Latent prints are invisible to the naked eye and must made visible, then preserved, analyzed, and compared. The smoother and less porous a surface the greater the chances for lifting the prints. These are among the most common and valuable types of physical evidence
Visible Fingerprints (Patent prints) are visible prints that are left on a hard surface that leave a distinct ridge impression occur when a foreign substance on the skin of a finger is transferred to the surface of another object. Blood, paint, ink, etc. Can occur on a variety of surfaces smooth or rough, porous and nonporous. Wood, metal, clothe, glass, etc
Plastic Fingerprints are visible prints that are left on a soft surface and most likely 3 dimensional Soap or wax freshly painted object or fresh caulk or any substance that will soften when hand held and then retain the finger ridge impressions. Are impressed onto an object and can easily be observed
How to collect patent fingerprints Very simply – photography The prints are photographed in high resolution with a forensic measurement scale for reference If need be investigators can improve the quality of the photo through Light adjustment Using alternate angles Chemicals and dyes
How to lift latent prints Dusting with fingerprint or magnetic powder Smooth or nonporous surface Prints are then photographed and then lifted with clear tape. The tape is placed on a latent lift card. Cyanoacrylate – superglue fuming of a surface before applying powders or dyes Nonporous surfaces Fumes adhere to the prints allowing them to be viewed Superglue fuming also allows prints to be lifted more than once Chemical Developers: ninhydrin Used on porous surfaces, such as paper The chemicals react with amino acids and inorganic salts, from bodily fluids, left behind with the print Turns the print purple so it can be easily photographed
Demo Videos Dusting-basic fingerprint lifting Superfuming Magnetic Powder Iodine/Ninhydrine Spray fingerprint powder Pop and Fume Fume Chamber Lifting prints on irregular surfaces with Mikrosil