| What kind of powder is used when CSI's embark on | | | | brush leaves behind magnetic powder when it is |
| the search for fingerprints at a crime scene? In this | | | | passed over the fingerprint, and the fingerprint all of |
| article, I will attempt to explain the various types of | | | | a sudden shows up. |
| fingerprint powders that investigators use to find | | | | Other special types of powders are fluorescent. |
| prints left behind by an offender. | | | | After they are applied, the fingerprint glows under a |
| What do fingerprint powders do? Fingerprint powders | | | | laser light source. |
| stick to moisture and oils of the residue in a latent, or | | | | After the powdering process is done, the fingerprint |
| invisible, print and thereby reveal the pattern of the | | | | is either documented via photograph or lifted. Lifting |
| friction gyri, or ridges. Fingerprint powders come in a | | | | is a procedure done by gently laying the sticky side |
| variety of types and colors. Criminal scientists use the | | | | of a strip of transparent tape such as Scotch |
| color that gives the highest amount of contrast with | | | | packaging tape over the fingerprint. As the tape is |
| respect to the background surface. Black powder, | | | | removed, the fingerprint pattern sticks to the sticky |
| which is made from charcoal or carbon black, and | | | | surface of the tape. The tape is then put on a card |
| gray powder, which is made from titanium or | | | | for later study and comparison. Because smears can |
| aluminum powder, are most commonly used. | | | | damage fingerprint evidence, it is essential that hands |
| Powders that interact with magnets are also used. | | | | like a surgeon are used when performed the lifting |
| These powders too come in different colors. These | | | | procedure. |
| powders are used with a special magnetic tool that | | | | When you watch your favorite CSI program, you will |
| resembles a brush. It is not a real brush because it | | | | be familiar with this method of using magnetic |
| contains no bristles, and thus does not come in | | | | powder dust to discover invisible fingerprints. |
| contact with the fingerprint thus destroying potential | | | | Whenever you hear a CSI technician "dusts (an |
| evidence via smearing or damaging the fingerprint. It | | | | object) for fingerprints," you will know what they are |
| is more like a tiny feather duster that loosely holds | | | | talking about. |
| the powder by a weak magnetic force. This so-called | | | | |