PHYSICAL DEVEOPER

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Chemical Name:
PHYSICAL DEVEOPER
Surface Used On:
Porous surfaces, especially currency & paper. Effective on wet items.
Sensitive To:
Sebaceous components.
Development Color: Method to Record: Hazard: Protective Clothing: Fume Hood Use:

Light-Dark Gray

Not
Reagent Characteristics

Development Complete When:

Source of Error:

Incompatibilities:

Precautions:

Storage Container:

Safety:

Recommendations:


Similar Reagents



Sequential Reagents



Abridged Reagent Sequence


Visual Examination
|
Forensic Light
|
D.F.O.
|
Ninhydrin
|
*** Physical Developer ***
|
Sodium Hypochlorite


PHYSICAL DEVEOPER FORMULA:


	Maleic acid pre-wash:
 
50 grams Maleic acid powder
dissolved in 2 liters 
of distilled water.
 

	Commercial Working Solution:
 
1 part solution A 
   (5ml. /10ml. /15ml.)
 
To 18 parts solution B 
   (90ml./180ml./270ml.)
 
PROCEDURE OF APPLICATION

The item is immersed into a series of baths each placed upon a mechanical 
rocker / shaker platform in order to keep the reagent in suspension and 
to assure complete washing.  Use of non-metal tongs and forceps to 
handle the porous items is recommended.

A.
 Pre-wash (10 minutes)
B.
 Working solution  (20 minutes)
C.
 Rinse (5 minutes)
D.
 Rinse (5 minutes)
E. 
 Air dry the item while lying flat.


Ridge Detail Visualized by:

Visible chemical/stain reaction.


Reagent Applicabilities:

Porous sufaces
Post-Ninhydrin
Raw Wood surface
Wet surface


Other Chemical Name(s):

P.D.


Working Solution Shelf-life:

Prepared as needed. Working solution is likely to become exhausted upon use.

Process Summary:

This is a multi-solution, multi-step process that can be used as a follow-up to ninhydrin cases. This is the technique of choice for paper currency items, and porous items that may have been wet.

Accepted Deviations:

Commercial or Laboratory-prepared mixtures are used. Physical Developer also develops indentations in paper surfaces, therefore FW/TT impressions may be enhanced.

Experiments have shown that vinegar may be used in place of other acids as a pre-wash.

Supporting Reference Materials:

1. Lee, H.C. and Gaesslen, R.E. (1991), “Advances in Fingerprint Technology”, Elsevier, pp. 104-115.

2. Technical Note No. 1-2730 "Physical Developer Kit", Lightning Powder Co., Inc. (1990)

3. "Manual of Fingerprint Development Techniques 2nd. Ed., Home Office - Police Scientific Development Branch, White Crescent Press, Ltd., Luton, England, 2001.

4. "Chemical Formulas and Processing Guide for Developing Latent Prints", U.S. Dept. of Justice, pg. 47-48, 1994.

5. Rawji, A. and Beaudoin, A., “Oil Red O Versus Physical Developer on Wet Papers: A Comparative Study”, Jor. Forensic Identification, vol. 56, no. 1, 2006, pp. 33–54.

6. Lennard, C. and Margot, P., “Sequencing of Reagents for the Improved Visualization of Latent Fingerprints”; Jor. Forensic Identification, September/October 1988, vol. 38, no. 5, pp. 197-210.

7. Fingerprint Development Techniques, Kent, Terry, ed., Heanor Gate Publisher, Derbyshire, England, 1993.

8. Phillips, C., Cole, D and Jones, G., “Physical Developer: A Practical and Productive Latent Print Developer”; Jor. Forensic Identification, 1990, vol. 40, no. 3, pp. 135-147.

9. Fingerprints and Other Ridge Skin Impressions, Champod, C.; Lennard, C.; Margot, P.; Stoilovic, M. CRC Press: Boca Raton, FL, 2004, pp. 131-133.

10. Ramotowski, Robert, “Comparison of Different Physical Developer Systems and Acid Pre-treatments and Their Effects on Developing Latent Prints“, Jor. Forensic Identification, vol. 50, no. 4, July-August 2000, pp. 363-383.

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