Wetwop Black /White

Introduction

Wetwop is used to process the sticky-side of adhesive tapes and labels for latent prints. As with any development 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 (due to poor contrast)
• Some paper labels and tapes and labels with dried-out adhesives
• Some contact papers or shelf papers

Wetwop™ - Black was developed to process the adhesive surfaces of all 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 adhesive surface, shake the bottle thoroughly. Pour a small amount in a clean beaker or dish. Using a small camelhair brush, apply Wetwop™ to the adhesive with a painting action. Completely cover the surface. Let the solution sit on the tape for 10-20 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.

Wetwop™ has been tested against Sticky Side Powder^® processed tapes and was able to develop prints that were not detected by Sticky Side Powder^®. In some instances, Wetwop™ was able to enhance prints developed by Sticky Side Powder^®.

Photography

Photography of latent prints developed with Wetwop™ should not pose any problems.