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

Method One

• Place approximately equal amounts of water, Photo-Flo 200 and Sticky-side Powder™ into a small jar or beaker. It should be the consistency of thin paint. More liquid or powder can be added to make the mixture thicker or thinner as the need dictates. Mix a total volume suitable for the application at hand.
• Use a small brush or camelhair fingerprint brush to "paint" the liquid mixture onto the adhesive side of the tape or label. This method has also been found to work on the back side of some tapes.
• Leave it on for 10 to 15 seconds and then rinse it off with water. The tape can be rinsed under running water, but the preferred method is to gently agitate it in a bowl of water.
• When most of the solution is rinsed off of the tape or label, examine it. Photograph any developed latent prints.
• If the solution is left on too long, it becomes difficult to rinse off. The solution will adhere too strongly to some tapes and labels. The solution may be applied but it must be rinsed immediately. The other alternative is to use Meth od Two for these types of tapes and labels.

Method Two

• An alternative method for processing adhesive tapes and labels which are not suitable for the painting process, is a soaking process. Add some Sticky-side Powder™ to a bowl or tray of water. The rinse water left over from Method One can be saved and used for this method.
• Agitate the bowl of water to stir up the Sticky-side Powder™ and submerge the tape pieces or labels with the sticky side up.
• Allow the floating particles of Sticky-side Powder™ to settle on the tape. This process may take some time to develop the latent prints. The resulting prints may also be rather faint.

Method Three

• Another variation is to add some Sticky-side Powder™ to a bowl or tray of water which can be closed. The rinse water left over from Method One can be saved and used for this method.
• Agitate or shake the container to stir up the Sticky-side Powder™ until a large head of foam appears.
• Pass or draw the tape through the foam only.
• Rinse the tape as usual.

Introduction

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.

Caution

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.

Disclaimer

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.