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Technical Note
Wetwop™ – Black/White
Wetwop™ – Black
Wetwop™ – White
Introduction
Wetwop™ is used to process the sticky-side of adhesive tapes and labels for latent prints. As with any chemical process, we suggest that you experiment on non-evidence items to become familiar with this process before using it on evidence.
Wetwop™ can be used on the following adhesive surfaces:
- Duct tape
- Adhesive bandages
- Paper-backed labels
- Masking tape
- Plastic surgical tape
- Clear plastic tape
- Packing labels
- Double-sided foam tape
- Reinforced packing tape
- Cloth surgical tape
- Adhesive edge of 3M™ Post-it® notes
- Frosted plastic tape
- Black electrical tape
- Some paper labels and tapes and labels with dried-out adhesive
- Some contact papers or shelf papers
Wetwop™ – Black was developed to process the adhesive surfaces of most colors. The solution will stain the residues of the fingerprint deposited on the adhesive surface. The solution has little background staining.
Wetwop™ – White was developed to process dark colored and clear adhesive surfaces. The solution will stain the residues of the fingerprint deposited on the adhesive surface.
In some instances, both black and white solutions can be used in sequence to present a contrast for better visualization of the prints.
Safety
As with any new chemical process, read and understand the Material Safety Data Sheet on all of the chemicals involved. Practice normal industrial hygienic procedures of wearing lab coats, protective gloves, and goggles, if there is any risk of splashing the solution into the eyes.
Processing Instructions
A visual examination of the evidence should be conducted prior to any chemical processing. Any foreign material should be collected in accordance to laboratory procedures.
If the tape is wadded or stuck on another surface, efforts should be made to remove and expose the adhesive surface with out destroying the adhesive side. Once that is accomplished, a second visual examination should be conducted. Any evidence of ridge detail should be photographed prior to processing.
To process the tape, shake the bottle thoroughly. Pour a small amount in a clean beaker or dish. Using a small camelhair brush, apply Wetwop™ to the adhesive side of the tape with a painting action. Completely cover the surface. Let the solution sit on the tape for about 15-30 seconds. Rinse the solution off the tape with a gentle stream of tap water. Once the tape is rinsed, set aside and allow to dry. Do a visual examination and photograph the results.
Photography
Photography of latent prints developed with Wetwop™ should not pose any problems.
Ordering Information
Catalog No. 1-0077 Wetwop™ – Black
Catalog No. 1-0078 Wetwop™ – White
Introduction
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The goal of latent print examiners and technicians is to discover and
collect latent prints by various means. The ultimate goal is
to identify those latent prints to the person responsible
for the criminal act and prosecute them to the fullest
extent of the law. Some of these means to develop latent
prints include processing evidence and other surfaces using
powders, chemicals and lighting techniques. The purpose of
this booklet is to provide a resource of information about
latent print processing techniques. This booklet does not
contain every process available and does not claim to be all
inclusive of all variations of processes. The information
has been collected from various sources.
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Caution
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This booklet
contains descriptions of processes utilizing chemicals or
combinations of chemicals which may be hazardous to the
user's health. It is strongly recommended that proper
precautions be taken when using hazardous chemicals or
combinations thereof. Safety equipment needed may include
fume hoods, gloves, protective clothing, safety goggles,
splash shields or respirators. It may be necessary to store
these chemicals in specific containers or cabinets. It is
the user's responsibility to know and use the proper and
adequate safety equipment required the various chemicals
listed.
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Disclaimer
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Lightning Powder
Company, Inc. assumes no responsibility for the use or
misuse of any of the chemicals, procedures, methods of ideas
described herein resulting in injury and/or damage to
persons or property.
Copyright © 2005 Lightning Powder Company,
Inc.
The material contained in and displayed by this Web site may be reproduced
with acknowledgment of its source.
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