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TI02-46ENG-REV4 SIRCHIE ® 100 HUNTER PLACE YOUNGSVILLE, NC 27596 USA Phone: (919) 554-2244, (800) 356-7311 Fax: (919) 554-2266, (800) 899-8181 Finger Print Laboratories Website: www.sirchie.com E-mail: [email protected] TECHNICAL INFORMATION Physical Developer Catalog Nos. LPD100, LPD101 INTRODUCTION Physical Developer is a silver-based aqueous reagent that reacts with components of sebaceous sweat to form a silver/gray deposit. The process is effective on porous surfaces such as paper, cardboard, raw wood, tissue paper, paper-based adhesive tapes, and some man-made fibers. It is seldom used as the primary method of latent print development; rather, it is used as a follow up to processing with DFO and/or Ninhydrin. Since it reacts with sebaceous compounds, it is often likely that additional prints or detail will develop that were not discovered when using other processes that react with amino acids. Physical developer is not suitable for use on non-porous surfaces. Physical developer may interfere with forensic examinations of handwriting, inks, indented impressions, body fluids including DNA profiling, fibers, hairs, paint and other examinations. Physical Developer is a sensitive, complex formula requiring special handling. Use of this product should be limited to experienced personnel only. BACKGROUND Physical Developer contains chemicals that can be harmful and fatal if taken internally. The material can be used safely if all precautions listed herein and in the Material Safety Data Sheets (MSDSs) are followed completely. Sirchie supplies Physical Developer in two-part, pre-mixed containers. Solution “A” and Solution “B” should not be combined until just prior to use. Some forensic laboratories have recommended an acid pre-treatment prior to using Physical Developer. We have pre-treatment formulas for those wishing to use them. Physical Developer will develop latent prints known or suspected to be several years old. PRECAUTIONS Before using this kit, consult the appropriate Material Safety Data Sheets (MSDS) found on our website at www.sirchie.com and click on MSDS. Wear protective clothing (lab coat or apron), non-porous gloves and safety glasses when preparing or using this reagent. Avoid exposure to the skin. Oral ingestion of silver nitrate can be fatal. Collect used Physical Developer solutions in an appropriate container for disposal by the proper authority. If the item(s) is of no further forensic or evidential value, articles treated with Physical Developer may be returned to the owner or discarded as ordinary waste. Physical Developer is especially sensitive to any contamination present. Be certain to wash all containers to be used in warm, soapy water. Rinse thoroughly with tap water then rinse three times with distilled water. Any residual chlorine from tap water may cause adverse reactions with the silver compound in Physical Developer. Wet documents that have soaked in the following solution(s) can be very fragile. Use extreme care when handling these specimens. If possible, use tweezers or tongs that do not have serrated tips to prevent leaving indentations in the paper that may cause it to tear. If you are performing a sequence of examinations, begin with DFO, and then examine with UV light. Ninhydrin treatment should follow. Physical Developer should be the last step, and no further treatment with other chemicals should be attempted. Copyright© 2008 by SIRCHIE® Finger Print Laboratories, Youngsville, N.C. All Rights Reserved. TI02-46ENG-REV4 PROCEDURE CAUTION: Solutions “A” and “B” should not be mixed together until you are prepared to process evidence for latent fingerprints. If stored in a darkened cabinet, the shelf life of the combined solutions is several days, depending on the depletion of the silver nitrate component. Depletion of the silver content can be anticipated if a large number of items are processed, and this, of course, will shorten shelf life and usefulness of the solution. Uncombined solutions can be stored at room temperature (or cooler) until the date stamped on Solution “B” has passed (approximately six months). Do not use Solution “B” after the expiration date. Do not transfer either Solution “A” or “B” to other containers of clear glass or plastic as these reagents are light sensitive and will degrade and will lose their effectiveness. Preparation of Physical Developer Working Solution 1. Physical Developer (PD) working solution is made by combining one (1) part Solution “A” with eighteen (18) parts of solution “B” in a clean glass or plastic tray (do not use metal trays) and stirring with a glass or plastic rod, or agitating for approximately one (1) minute. 2. The following are examples of measured quantities of working solutions: Solution “A” 5 ml 20 ml 50 ml Solution “B” 90 ml 360 ml 900 ml 3.Prepare only as much working solution as is necessary to cover the item being processed with a depth of about 5 mm of solution. Formula for Preparing A Pre-Treatment Stock Solution Caution: Be certain to consult the MSDS for the following chemical prior to mixing and use. Some laboratories recommend and use a pre-treatment solution. 1. Using a clean, 2 liter glass beaker, add 1 liter of distilled water. 2. Add 25 grams of MALEIC ACID and stir with a magnetic stirrer until all of the solid material is dissolved. 3. Transfer the MALEIC ACID solution to a clean container. Unused MALEIC ACID solution will keep indefinitely. Place an appropriate label on the container. 4.Recommended pre-treatment involves allowing the document to soak in the MALEIC ACID solution for up to 10 minutes or until all bubbling action stops. 5. Follow instructions for processing with Physical Developer. Processing Evidence With Physical Developer Use a clean glass or plastic tray. The kinds of trays used in darkroom processing are ideal. 1. Place the specimen (document, envelope, etc.) into the working solution prepared above. 2. If latent fingerprints are present, they will begin to develop in about 5 minutes. Remove the specimen from the solution when the background begins to develop to a significantly dark color—usually about 15 minutes. Overdevelopment will cause the latent prints to lose contrast with the background color. 3. After removing the specimen from the developing tray, carefully place it in a second glass or plastic tray, and then rinse with running water for about 5 minutes to prevent excess staining. 4.Remove the item from the rinse tray, and allow it to air dry at room temperature. 5. Photograph any useful prints after the specimen is completely dry. 6. Low contrast prints may be improved by reprocessing, but only after photography is complete. 7. To reprocess specimens, remove any residual chlorine (from tap water) by immersing the specimen in distilled water. (Reprocessing should take place within a few hours after the original developing procedure.) If reprocessing is to be attempted, do not use any pre-treatment. Repeat steps 2 to 5 above. 8. When processing is complete, to prevent staining, wash and rinse all trays and utensils used in the process. Photography Latent fingerprints developed with the Physical Developer process are gray in color and do not usually present any particular photographic problems. Diffused illumination is usually satisfactory, but in some cases oblique lighting may be useful. The use of high contrast lithographic films may be useful if the latent prints are very faint. Fluorescent examination may also prove useful, particularly if a confused background is present. On some materials, the background may also fluoresce and the developed prints will absorb the illuminating light. Use of an alternative light source is recommended, due to its wide spectrum of UV light.