Development of Latent Prints
On Adhesive Material
Written By Dustin J Calvin
Administrative Advanced Latent Fingerprint School
98th Session
January 12 � 30, 2004
FBI Academy
Quantico, Virginia
Obtaining latent prints from the adhesive side of materials has been a challenge to law enforcement agencies for many years.
Several different methods and techniques have been tested and used for developing latent prints on the sticky side of various
types of tape. The type of tape being processed for latent fingerprints will determine the processing method and technique
used.
A method that was reported successful for developing latent prints on light colored cellophane tape was the use of
aqueous solutions of crystal violet or Victoria page blue. Gentian violet or crystal violet is a toxic dye stain that reacts
with the sebaceous materials in latent prints. The dye produces a purple color that can be enhanced with a yellow-orange light
source. The use of gentian violet (crystal violet) was reported to be successful developing latent prints on the sticky side
many other various types of tape. Gentian violet produces poor contrast of the developed latent print on dark-colored tape.
It is reported that in this instance the latent print can be transferred to a white background by using transparent lifting
tape.
Using fluorescent dye stains to process the sticky side of tape for latent prints has also been reported to be successful.
The dye stain, Mikephor, was reported to be successful for developing latent prints on black electrical tape. A UV light is
needed to visualize the latent prints when using the Mikephor. Other fluorescent reagents reported being successfully used are
o-phthalaldehyde and 8-anilino-1-napthalene sulfonic acid. The use of Ardrox in a detergent solution was reported to work well
on dark-colored sticky surfaces where gentian violet worked poorly.
A more complex method used to develop and visualize latent prints on black tape is the use of crystal violet and photographic
paper. The stock solution of this method is 1.5g of crystal violet and 100mL of ethyl alcohol. The working solution is 10mL
of the stock solution and 500mL of distilled water. The working solution is brushed onto the adhesive side of the tape with a
camel-hair brush. You then dry the tape surface with a hot hair dryer and expose it to a high-intensity lamp until the latent
prints develop. Photographs are then taken of the developed latent prints before continuing with the process. The developed
latent prints are then transferred onto photographic paper by placing the tape between two pieces of photographic paper. The
emulsion side of the photographic paper should face the tape to form a sandwich. You then place the sandwich of tape and
photographic paper between two pieces of 1/8� thick blotter paper. The blotter paper is heated with low temperature using an
iron. The latent prints are transferred to the photographic paper and should be photographed.
Another successful and commonly used method for developing latent prints on the sticky side of tape is ash-gray powder
suspended in a PhotoFlo solution. This solution is then painted onto the tape surface and then rinsed off with cold water.
A similar method used is a black powder suspended in a mixture of detergents. The type of powder used is determined by the
color of the tape being processed. The different powder solutions reportedly work best in developing eccrine prints.
The Michigan State Police Lab conducted a study to determine the best method to use when processing the sticky
side of tape for latent prints. The methods tested were gentian violet (standard solution), �Sticky-Side Powder� (Japanese
solution), and a home made version sticky side of tape powder consisting of distilled water, Liqui-Nox glassware soap, and
Lightning black power. The types of tape that were tested were band-aids, bemistape, black vinyl tape, blue labeling tape,
cellophane tape, cloth tape, double sided cellophane tape, evidence tape (various brands), duct tape, frosted vinyl tape
(lifting tape), green vinyl tape, paper tape, post-it note adhesives, reinforced packing tape, and frosted scotch tape. Both
eccrine and sebaceous prints were deposited on the various types of tapes and processed with the above-mentioned processes.
Their conclusion stated that the home made version of sticky side of tape yielded the best results on both the eccrine and
sebaceous prints that were deposited on all of the tapes involved in the study. The �Sticky-Side Powder yielded the second
best results and gentian violet yielded the worst results.
Another study on processing the sticky side of tape was conducted by participants in a workshop and members of the US Secret
Service Forensic Services Division Identification and Research Branch at the 1997 IAI Conference at Danvers. This study
compared �Sticky-Side Powder� to a home made sticky side powder. The home made sticky side powder consisted of distilled
water, clear liquid dish soap, and black or white powder. Prints were deposited onto gray duct tape, strapping tape, tan
packaging tape, and black electrical tape and processed with the two above-mentioned methods.
Their results reported that the home made sticky side powder yielded better results than the �Sticky-Side Powder�. They also
reported that you should moisten the tape prior to applying the solution to increase the contrast in the print. They stated
you should superglue and process the smooth side of the tape before processing the sticky side.
Bonnie L. Martin with the Oregon State Police used a similar home made sticky side powder in an actual case. The home made
sticky side powder used consisted of Kodak Photo-Flo 200, ash gray fingerprint powder, and water. It was applied to the
adhesive side of a piece of black electrical tape and produced latent prints of high quality that were individualized to the
victim in the case.
A method similar to the homemade versions of sticky side powder is titanium dioxide. Titanium dioxide is a paint pigment
used by paint manufactures and is available in many different grades. The rutlie Kemira 820 grade of titanium dioxide is
reported to yield the best results. The mixture consists of two parts titanium dioxide and one part Kodak Photo-Flo. This
mixture is applied to the surface of the tape with a camel-brush. This method reacts with both eccrine and sebaceous prints.
The benefit to this method is that it is reported to develop prints on both the sticky side and smooth side of duct tape and
electrical tape. Titanium dioxide is a white colored substance therefore it works best on dark colored tapes. An alternate
light source set at 300 � 400nm using orange colored goggles will enhance the developed prints on light colored tapes.
Another way to mix the titanium dioxide is to add it to a 50/50 mixture of water and Photo-Flo in a container until it is the
consistency of milk. The tape is then gently agitated in the solution for approximately one minute and rinsed in cold water.
The developed latent prints are then photographed.
All of the above-mentioned methods have been reported to develop latent prints on adhesive materials. You must experiment with
all of the methods in order to determine the one that works best for you. Every case is different and you may not use the same
method each time. Therefore, you should be aware of all of the methods that are available in order to choose the most effective
method at that time.
References:
1. Wade, D.C. Development of Latent Prints with Titanium Dioxide (TiO2). J. For. Ident. 2002 52 (5), 551-559
2. Martin, B.L. Developing Latent Prints on the Adhesive Surface of Black Electrical Tape. J. For. Ident. 1999 49 (2), 127-129
3. Bratton, R. and Gregus, J., Development of a Black Powder Method to Process Adhesive Tapes. Fingerprint Whorl, January, 21,1997
4. Nelson, J. (1998, March/April). Homemade Solution for Processing Latent Prints on the Adhesive Side of Tape. The Print, 14 (2), 1-2. Retrieved January 15, 2004, from http://www.scafo.org/library/140201.html
5. Lee, H.C., and Gaensslen, R.E. (Eds.). (2001). Advances in Fingerprint Technology (Second Edition). CRC Press: Boca Raton, London, New York, Washington, D.C.
6. Menzel, R.E. (1999). Fingerprint Detection With Lasers. New York: Basel.
7. Fisher, B.J. (1993). Techniques of Crime Scene Investigation (Fifth Edition). CRC Press: Boca Raton, Ann Arbor, London, Tokyo.
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