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Development Color:
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Method to Record:
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Hazard:
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Protective Clothing:
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Fume Hood Use:
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Formula
Procedure of Application
Development Complete When
Source of Error
Incompatibilities
Precautions
Storage Container
Safety
Recommendations
Similar Reagent
Sequential Reagents
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
Development Complete When
A background staining of item becomes apparent. Source of Error
Glassware MUST be absolutely clean. Creases and damage to the item causes the solution to develope their appearance. Cyanoacrylate is detrimental to this process. Incompatibilities
Items that disintegrate in water solutions. Thermal fax papers, blueprints and photostats with an alkalinity factor above pH 7 will become completely stained. Items that cannot be effectively rinsed of the working solution. Items to be submitted for Questioned Document Examination. Precautions
The working solution MUST be mixed in the order listed !! Be sure to agitate the working solutions to optimize development. Processing should be done away from direct sunlight. Use clean GLASS labware. Storage Container
Working solution is made fresh with each application. The Silver nitrate solution is stored in a dark stoppered container. Safety
Avoid getting solution stains on your skin and clothing. Recommendations
Use a rocker platform (orbital shaker) to keep the working solution in suspension. Use non-metal tongs and forceps to handle items. P.D. is used as a post-D.F.O. and post-Ninhydrin process, and is used especially on currency. Similar Reagent
Sequential Reagents
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Chemical Name
Physical Developer Surface Used On Porous Surfaces, especially currency & paper. Effective on wet items Sensitive To Sebaceous Components Abridged Reagent Sequence
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Ridge Detail Visualized by:
Visible chemical/stain reaction Reagent Applicabilities: Porous Surfaces Post Ninhydrin Raw Wood Surfaces Wet Surfaces Other Chemical Name(s): P.D. Working Solution Shelf-life: Prepared as needed. |
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.
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.
Commercial or Laboratory-prepared mixtures are used. Physical Developer also develops indentations in paper surfaces, therefore FW/TT impressions may be enhanced.
Supporting Reference Materials:
- Technical Note No. 1-2730 "Physical Developer Kit", Lightning Powder Co., Inc. (1990)
- "Manual of Fingerprint Development Techniques 2nd. Ed., Home Office - Police Scientific Development Branch, White Crescent Press, Ltd., Luton, England, 2001.
- Navarro, R.L., "Chemical Enhancement of Questioned Footwear Impressions", North Carolina State Bureau of Inv., 1992.
- "Chemical Formulas and Processing Guide for Developing Latent Prints", U.S. Dept. of Justice, pg. 47-48, 1994.
- Advances in Fingeprint Technology 2nd. Ed., Lee, H.C. & Gaensslen, R.E., CRC Press, Boca Raton, FL., 2001.
- Technical Notes, Lightning Powder Co. Inc., Salem, OR., 2001.