Electrostatic Dust Print Lifting Devices

Topics - Electrostatic Dust Print Lifting

Background Information

Operational Precautions

Pathfinder Device

Stun Gun Usage

Articles - The Recovery of Dust Print Impressions

Background Information:

Electrostatic Dust Print Lifting Devices operate by charging a lifting film which has been placed over a surface bearing a dust print impression. During operation, the electrostatically charged lifting film is drawn down to the surface, and the dust particles in the impression are attracted to the lifting film. The construction of the lifting film allows it to store the electrostatic charge, thus retaining the dust particles, after the power supply has been disconnected. The impression-bearing film is then viewed with an oblique light source to search for any impressions that have been recovered.

The power supply generates either a low-powered electric field of direct voltage, or by generating an impulsive electric field of high voltage. The stronger the electric field, the stronger is the device's ability to attract dust impressions to the lifting film.

Most devices are packaged as "Kits" to include additional equipment for the recovery, storage and viewing of dust impressions. Products may be deemed as "wireless" or not. All products may be regarded as portable.

These devices have been used to successfully recover dust impressions on the following:

• Paper
• Linoleum
• Seat Covers
• Wood
• Carpet
• Asphalt
• Concrete

Operational Precautions:

• It is wise to photograph visible dust impressions prior to electrostatic lifting.
• Before use, completely remove any previously lifted dust impression from the lifting film.
• Do not allow the lifting film to touch the ground plate during the lifting process. This causes the 'suction' action to be diminished, thus the dust particles are not fully attracted to the film.
• Air bubbles need to be 'rolled out' to prevent voids in the film.
• Allow the charge to dissipate before removing the film. A static shock is possible, especially on metal surfaces.
• Never make a final evaluation of the success of this lifting process until examining the film in a darkened room with oblique lighting.
• Properly label each lifted impression.
• Do not store or transport the impression-bearing lift in plastic packaging.
• The 'heart' of these devices is a rechargeable battery. Do not let the device loose its charge. Recharge regularly as instructed by the manufacturer.

Pathfinder® Electrostatic Dustprint Lifter

This is a device being marketed as a wireless, ergonomic, pocket-sized product. Wires have been eliminated, however, a small metal plate is used in conjunction with this device and the lifting film. Trials have shown that there is no significant difference in the lifting ability of this device as compared to traditional units.

This device uses a minaturized version of a voltage multiplier circuit. A safety feature is that this device when activated will not make a metal surface 'live'.

Stun Gun Usage

A Stun Gun may be modified to perform comparably to commercially marked electrostatic devices. These devices can generate 40,000 + volts at 3 to 5 milliamps. Arcing can be generated between the device and the lifting film during operations.

The stun gun is modified by placing small wire nut over each of the "Test Probes" at the "head" of the unit. This is done in order to prevent the unit from arcing during operation.

Typically, the lifting film is charged with the stun gun activated within 1/4 inch of the film with the "Contact Probes" facing the edge of the film. The device is moved along the perimeter of the film, to insure that the whole film is drawn down to adhere to the surface bearing the dust impression. After waiting 10 seconds for the charge to dissipate, the film can be handled.

Articles on the Recovery of Dust Print Impressions

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