Summary
Highlights
The video introduces three types of fingerprints: latent, patent, and plastic. Latent prints are invisible and need development, patent prints are made in a substance like blood, and plastic prints are three-dimensional, like in chocolate or putty. Today's focus is on lifting a latent print.
To lift a latent fingerprint from a desk, magnetic fingerprint powder and a magnetic fingerprint wand are used. The wand picks up magnetic fibers when depressed and releases them when pulled. The fibers are gently applied to the surface without the wand touching it, developing the fingerprint.
Fingerprints are composed of sweat, oil, and protein, with the magnetic fibers adhering to the oil. The choice of fingerprint powder and tape depends on the surface. Diff-lift tape is used for collection, with a small end folded for easy grabbing. The amount of tape needed is judged by the developed print size.
The diff-lift tape is carefully applied over the developed print, smoothed down, and then peeled off. The lifted print is then transferred to a glossy lift card. The back of the lift card can be used to diagram the lift location and record case information. The final step is to smooth the tape onto the lift card, revealing the lifted latent fingerprint.