Procedures for Collecting and Lifting Fingerprints

Once the fingerprints are developed and photographed, there are several techniques that can be used to lift the fingerprints for further analysis and storage. There are hinge lifters, rubber lifters and cellophane tape.

Hinge lifters come in many different color backgrounds to allow for the visualization fingerprints developed with different color powders. The hinge lifter is placed on the print and pressed down evenly. The lifted print is covered with the hinged cover and is protected from scratches and dirt. Using a roller can sometimes help to smooth the cover to avoid bubbles. An image of the fingerprint is obtained just as it was found.

When using a rubber lifter, the plastic cover should be carefully removed in one steady movement since any pause will result in a line being left on the tape. The adhesive side of the tape should be applied to the powdered print, and pressed down evenly. Then the tape is peeled from the surface in one smooth, even motion. The plastic cover is replaced on the tape over the lifted print to protect it. A negative image of the fingerprint is obtained.

Cellophane tape can be used on surfaces that aren’t flat. It attaches to the contours of the object in order to avoid bumps. A high quality clear transparent tape should be used not a glossy or opaque magic tape. A bit of tape is folded over to be used as a tab for handling and the tape is unrolled. The print area is covered about an inch beyond in the other direction. The tape is gently rubbed over the print. After the tape is firmly in place, the print is lifted by pulling the roll gently and evenly away from the surface. The tape must be quickly applied to a card or piece of paper and excess tape must then be cut away. Transparent lifting tape has the advantage of presenting the lifted fingerprints in the correct position rather than reversed as on the rubber lifters.

When using lifters, it is important that the handler not get their own fingerprints on the lifters. It is also important not to get air bubbles under the lifters. Bubbles destroy the value of the print and obscure the fingerprint.

Fingerprint lifts should have the date, hand, finger and initials of the person lifting the print. Clear lifts can be chosen so that a background color or backlight can be used to see prints. Lift color should be chosen that provides contrast to developing color.

http://www.odec.ca/projects/2004/fren4j0/public_html/lifting_techniques.htm