latent print procedures manual

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Department of Forensic Science

LATENT PRINT

PROCEDURES MANUAL

Latent Print Procedures Manual DFS Document 241-D100Issued by Physical Evidence Program Manager Revision 4Issue Date: 13-February-2012 Page 1 of 69


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Table of Contents

TABLE OF CONTENTS

1 Introduction2 Inherent Luminescence

2.1 Introduction2.2 Preparations2.3 Instrumentation2.4 Minimum Standards and Controls2.5 Procedure or Analysis2.6 Interpretation of Results2.7 References

3 Ninhydrin - Porous Items3.1 Introduction3.2 Preparations3.3 Instrumentation3.4 Minimum Standards and Controls3.5 Procedure or Analysis3.6 Interpretation of Results3.7 References

4 Physical Developer4.1 Introduction4.2 Preparations4.3 Minimum Standards and Controls4.4 Procedure or Analysis4.5 Interpretation of Results4.6 References

5 Powders5.1 Introduction5.2 Preparations5.3 Instrumentation5.4 Minimum Standards and Controls5.5 Procedure or Analysis5.6 Interpretation of Results5.7 References

6 Small Particle Reagent6.1 Introduction6.2 Preparations6.3 Minimum Standards and Controls6.4 Procedure or Analysis6.5 Interpretation of Results6.6 References

7 Cyanoacrylate Ester Fuming7.1 Introduction7.2 Preparations7.3 Instrumentation



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Table of Contents

7.4 Minimum Standards and Controls7.5 Atmospheric Chamber7.6 Vacuum Chamber7.7 Interpretation of Results7.8 References

8 Dye Stains8.1 Introduction8.2 Preparation8.3 Instrumentation8.4 Minimum Standards and Controls8.5 Procedure or Analysis8.6 Interpretation of Results8.7 References

9 Blood Protein Enhancement9.1 Introduction9.2 Preparations9.3 Minimum Standards and Controls9.4 Procedure or Analysis9.5 Interpretation of Results9.6 References

10 Gentian Violet10.1 Introduction10.2 Preparations10.3 Minimum Standards and Controls10.4 Procedure or Analysis10.5 Interpretation of Results10.6 References

11 Sticky Side Tape Powder Technique11.1 Introduction11.2 Preparation11.3 Minimum Standards and Controls11.4 Procedure or Analysis11.5 Interpretation of Results11.6 References

12 Post Mortem Recording of Friction Ridge Skin12.1 Introduction12.2 Scope12.3 Equipment/Materials/Reagents12.4 Standards and Controls12.5 Procedure12.6 Acceptance of Human Remains12.7 Storage of Human Remains12.8 Preparation and Recording Techniques12.9 Human Remains in Good Condition12.10 Desiccated Human Remains12.11 Interpretation of Results12.12 Information to be Placed on Cards Bearing Recorded Prints



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Table of Contents

12.13 Searching Unidentified Prints12.14 Case File Documentation12.15 Disposition of Human Remains12.16 Limitations12.17 Safety12.18 References

13 Friction Ridge Print Examination13.1 Introduction13.2 Analysis13.3 Comparison13.4 Evaluation13.5 Individualization13.6 Exclusion13.7 Inconclusive13.8 Verification13.9 Procedure and Documentation of Blind Verification of Individualization, Exclusion and Inconclusive

Results13.10 Deviation from the Blind Verification Policy13.11 Practices for Latent Print Scientific or Technical Casework Conflict Resolution13.12 References

14 Automated Fingerprint Identification System (AFIS)14.1 Introduction14.2 Procedures14.3 Performance Check

15 Report Wording15.1 Introduction15.2 Latent Print Section Report Wording Guidelines

16 Minimum Standards and Controls16.1 Chemical Processes16.2 Powder Processes16.3 Preservation of Impressions16.4 Information to be Included on Lifts and Photographs/Digital Images16.5 Control (Possession) of Lifts, Photographs/Digital Images and Negatives after Completion16.6 Photography16.7 Worksheets16.8 Laboratory Markings on Exhibits

17 General Instrumentation17.1 Alternate Light Source17.2 General Processing Equipment17.3 Powders and Particulate Application17.4 Powders17.5 Lifting Material17.6 Backing Material17.7 Magnifiers17.8 Specialized Processing Equipment17.9 Heat/Humidity Chambers



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Table of Contents


17.10 Specialized Light Sources17.11 Cyanoacrylate Fuming Cabinets

18 Commonly Used Abbreviations


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1 Introduction

1 INTRODUCTIONWhile general procedures for evidence examination are usually divided into two categories, those for porous and thosefor nonporous surfaces; each of the categories contains an enormous variety of materials with individual properties thatmay enhance or diminish the effectiveness of a particular technique. The composition of palmar sweat is predictable to ahigh degree, yet the components of impression residue may include extraneous matter transferred to friction ridge skinfrom many possible sources. In some instances, techniques designed to better visualize the contaminants are moreproductive than those utilized to detect smaller or uncertain quantities of inherent palmar sweat composition. Othercircumstances may present a substrate which consists of material so similar to the residue that particular reagents willcause an overall reaction and prevent any distinction between impression and background.

In theory, any contact between the source of an impression and a surface results in a transfer of material between the twoobjects. Successful detection of that transfer to reveal a sufficient impression requires that the surface is receptive for adeposit, that is, relatively smooth, clean, and dry. The definition of "relatively" is imprecise and highly dependent uponthe nature of the transfer medium. Glass is receptive to palmar sweat transfer when dry but not when coated with dew,yet may be receptive to a deposit of sebaceous material even when submerged in water. A piece of metal covered with afilm of oil may be unreceptive to a deposit of sebaceous material yet provide a clear, distinct impression when touchedby dry, clean skin.

Residue once deposited is immediately subjected to environmental conditions. Heat, humidity, air movements, airbornecontaminants, chemical reactions and interactions, light, time, and moisture alter the condition and dictate the chances

for detection of any deposit. While any precise determination as to the effects surface condition, transfer medium, andsubsequent environment may have on the successful visualization of impression residue is impossible, one determinationis very clear. Most factors concerning the survival of the impression are negative and when of sufficient degree orcombined in various arrangements will diminish or destroy the likelihood of detection.

Visual examination of evidence is the first step in the processing procedure. Visual examination is the inspection forlatent print residue that may be preserved photographically or determined to be unsuitable as it exists. In addition, visualinspection is the mechanism by which processing procedures are selected from observation of the residue, its condition,and composition, and of the article. Expertise is the ability of an examiner to determine as many factors as possible andto select examination approaches accordingly. Examination documentation shall include each examination activityconducted, the sequence of those activities and the results of each examination activity. Examination activities include:development technique applied, photography/capture, AFIS/IAFIS search, and comparisons made.

Judgment of factors in the selection of processing approaches must be both tempered and augmented by a basicphilosophy toward evidence examination. Seeking a visualization of latent print residue, which may or may not bepresent, without tangible proof, creates a common dilemma regarding the extent of the pursuit. Negative results with anygiven technique are not a sure indication of non-existence and positive results with any given procedure do not provideassurance that the examination is complete. A basic philosophy which demands that exploration continues until allavenues are exhausted or until what is sought is found should guide all evidence examination procedures. Fixed methodsof even the best intentions requiring minimum processing steps, check lists, or pre-determined consequences are nosubstitute for dedicated and reasoned logic to find what is sought, the identity of the suspect whenever possible.

Known fingerprints or palm prints produced from Individual Characteristic Databases (ICDs) are treated as examinationdocumentation in accordance with QM 15.9. These hard copies may be received from Central Criminal RecordsExchange (CCRE - Virginia State Police), the Federal Bureau of Investigation (FBI), or local law enforcement agencies.They may be in the form of printouts from archival files (digital media) or facsimiles, photographic copies orphotographs from CCRE, FBI or local law enforcement agencies record files. These items are uniquely identified by theState Identification (SID) number, FBI number, or local Originating Agencys Case (OCA) number in conjunctionwith the local Originating Agencys Identification (ORI) number. The Department of Forensic Sciences Latent PrintSection does not maintain an ICD.

Short term storage is used when evidence is in the process of examination. The length of time evidence may remain inshort term storage will be thirty (30) days. After this time period, evidence must be placed into long term storageaccording to QM Section 14.9.1.1.



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1 Introduction


The Departments laboratory facilities provide sufficient environmental conditions to conduct all tests listed in thisProcedures Manual with no further consideration required.

Commercially purchased reagents are an approved alternative to laboratory prepared reagents. However, they still mustmeet the minimum QA/QC requirements for that particular reagent.

Small twist-tie baggie corners, small ziplock baggies (e.g., 1/2 X 1/2, 3/8 X 3/8, etc.) or 1/2 vials that are submittedin drug cases, will not routinely be processed for latent prints.

This Procedures Manual is arranged according to protocols for various types of substrate materials and residuesencountered in latent print processing. It contains further descriptions when surface condition and/or deposit factors are amajor influence upon technique selection. Additional factors may require some modification or adjustment to thetechnique or sequence of techniques indicated. In some instances procedures which fall into the general processingguidelines for a particular substrate but are inappropriate or destructive due to other factors should be modified so as toaccomplish the best possible processing sequence for that specific item. This Procedures Manual can not list everysubstrate an examiner will encounter in casework and all procedures are subject to revision as new techniques or researchreveals improvement.


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3 Ninhydrin Porous Items

2 INHERENT LUMINESCENCE2.1 INTRODUCTION

The use of alternate light sources in conjunction with various chemical techniques and dyes has proven veryeffective in visualizing latent impressions. Substances found in latent print residue may luminesce whenilluminated by the proper wavelength of light and viewed with the appropriate filters. B-vitamin complexes, thatare a natural component of perspiration, may be the cause of this reaction. Various contaminants such ascosmetics may become part of latent print residue and may inherently luminesce as well. Additionally certainmaterials such as styrofoam and galvanized or zinc plated metal are observed to consistently produce impressionsthat will luminesce without the application of chemical processing or dyes. This inherent luminescence allows forexamination of items that may be destroyed by other techniques.

Proper safety precautions including avoiding skin exposure and proper eye protection with appropriate opticaldensities should be utilized when operating ultraviolet light sources, or alternate light sources. Consult theappropriate users manuals for the safe use and appropriate eye protection for the specific piece of equipmentbeing utilized.

2.2 PREPARATIONSNo specific preparations required.

2.3 INSTRUMENTATIONAlternate Light Source

2.4 MINIMUM STANDARDS AND CONTROLSNot Applicable.

2.5 PROCEDURE OR ANALYSISThe procedure for this technique consists of examining the item with the alternate light sources using appropriatefiltration. Common wavelengths used are 488 nm, 510 nm and 514.5 nm. In most cases an orange barrier filter is

appropriate for examination. Some success may be seen with the use of ultraviolet light sources and the variouswavelengths produced by alternate light sources. The examiner must choose the appropriate filters and eyeprotection for these light sources and the wavelengths selected.

2.6 INTERPRETATION OF RESULTSItems can be examined for inherent luminescence without destruction of the item. Photographic preservation ofdeveloped impressions which may be of value for individualization is essential and must be accomplished as soonas possible. In addition many surfaces should be routinely examined using this technique as it has been shown toproduce consistent results. The item being examined may luminesce and this background luminescence mayimprove the contrast of visible impressions much as the use of metal salt post treatment of ninhydrin developedimpressions. This non-destructive process is a relatively simple technique that has been proven to be verysuccessful in producing positive results.

2.7 REFERENCES1. Dalrymple, Brian E.; J. M. Duff; E. Roland Menzel. Inherent Luminescence of Fingerprints by Laser;

IdentificationNews, January 1977, 22, 1, 3-6.

2. Menzel, E. Roland. Fingerprint Detection with Lasers; Marcel Dekker: NY, 1980; pp 108.



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3 NINHYDRIN POROUS ITEMS3.1 INTRODUCTION

Ninhydrin, or triketo-hydrindene hydrate, is an extremely sensitive indicator of alpha-amino acids, proteins,peptides and polypeptides. The reaction produces a violet to blue-violet coloring of these substances and iseffective even with older deposits and/or minute amounts of amino acids. While ninhydrin can be used on anysurface, processing normally is confined to porous items which are not water-soaked and do not contain inherentanimal proteins.

3.2 PREPARATIONSNinhydrin is readily soluble in most organic solvents. Working solutions of ninhydrin are governed by the natureof the solvent and the strength of the solution. Concentrations of the ninhydrin solution may vary according toapplication, but generally a 0.5% to 1.0% weight to volume mixture produces the best results. A 0.5%concentration is recommended for routine porous item processing. Ethanol, methanol, petroleum ether, andacetone have high damage potential but are acceptable for non-document porous material. Any of the listedsolvents may be used at the examiners discretion. Commercially prepared ninhydrin may be used, no specificpreparation is needed.

Recommended Preparation - 0.5% concentration:

3.2.1 Petroleum Ether3.2.1.1 Chemicals Required

10 grams Ninhydrin 60 ml Methanol 80 ml 2-Propanol (Isopropyl Alcohol) 1860 ml Petroleum Ether (Fill measured beaker to the 2000 ml Level)

3.2.1.2 Directions1. Dissolve Ninhydrin crystals in Methanol.2. Add 2-Propanol to Ninhydrin/Methanol solution and stir.3. Add Ninhydrin, Methanol, 2-Propanol solution to Petroleum Ether and stir.

3.2.2 Acetone3.2.2.1 Chemicals Required

25 grams Ninhydrin 4 liters of Acetone

3.2.2.2 DirectionsDissolve Ninhydrin crystals in Acetone.

3.2.3 Heptane3.2.3.1 Chemicals Required

33 grams Ninhydrin



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220 ml Ethyl alcohol (use Absolute Ethanol , DO NOT use Denatured Ethanol) 4 liters Heptane

3.2.3.2 Directions1. Dissolve Ninhydrin in Ethyl alcohol.2. Remove 220 ml of Heptane from bottle.3. Add Ninhydrin, Ethanol mixture to Heptane and stir.

3.2.4 Test Strips3.2.4.1 Chemicals/Materials Required

1 gram Norleucine 100 ml warm distilled water blotter papers

3.2.4.2 Directions1. Dissolve Norleucine in distilled water until clear.2. Saturate blotter papers and air dry.3. Cut papers in small pieces.

3.3 INSTRUMENTATIONA humidity chamber or a steam iron may be used to control the heat and relative humidity to accelerate thedevelopment of latent prints after processing.

3.4 MINIMUM STANDARDS AND CONTROLSProcess a test strip as in 3.5.1 or 3.5.2. If the test strip turns purple the working solution can be used to processevidence. This testing procedure must be performed for each working solution at the time the solution is made.Documentation of this process must be done in the form of a reagent log for each batch to include a batch number,established by month/day/year (060404). If additional batches are made on the same day, add an alpha character tothe batch number (060404a, b, c, etc.). The batch number must be placed on the original/working container.Documentation of this process must be included in the examiners notes by indicating a positive reaction byplacing a (+) adjacent to the procedure and by recording the batch number. This test shall be performed for eachcase. Reagent shall be stored in a dark bottle and have a shelf life not exceeding one (1) year.

3.5 PROCEDURE OR ANALYSISAll applications should be done in a fume hood.

3.5.1 Dipping3.5.1.1 Completely immerse each item to be processed in the working solution until the item is

completely saturated, usually five seconds or less. The item can be manipulated using tongs orforceps.

3.5.1.2 Remove and allow the item to dry completely.



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3.5.1.3 Place the item in the heat/humidity chamber at no greater than 80 degrees Celsius/176 degreesFahrenheit and between 60% and 80% relative humidity; or the item may be steam ironed. Acertified hygro-thermometer must be utilized to monitor the heat/humidity levels in the chamber.

3.5.1.4 Check the item periodically to monitor the impression development. Care should be taken not tosaturate the item with water vapor.

3.5.2 Brushing and SprayingLarger items which will not fit conveniently into processing trays can be saturated with the ninhydrinsolution using a soft bristle paint brush. The items may also be processed by spraying. Spray the item untilsaturated and air dry; then follow the instructions in 3.5.1.3 and 3.5.1.4.

3.6 INTERPRETATION OF RESULTSNinhydrin coloration is not permanent, and while some impressions have remained visible for years, others havefaded in a matter of days. Photographic preservation of developed impressions which may be of value forindividualization is essential and must be accomplished as soon as possible.

3.7 REFERENCES1. Cowger, James F. Friction Ridge Skin Comparison and Identification of Fingerprints; Boca Raton: CRC

Press, 1993.

2. Lee, Henry C.; Gaensslen, R. E., eds.Advances in Fingerprint Technology; Elsevier Science Publishers:NY, 1991.

3. Lennard, Christopher J.; Pierre A. Margot. Sequencing of Reagents for the Improved Visualization ofLatent Fingerprints;Journal of Forensic Identification, September/October 1988, 38, 5, pp 197-210.

4. Kent, Terry, ed. Fingerprint Development Techniques; Heanor Gate Publisher; Derbyshire, England, 1993.5. Olson, Robert. Scotts Fingerprint Mechanics; Charles C. Thomas Publisher; Springfield, IL, 1978.6. Pounds, C.A.; R.J. Jones. Physicochemical Techniques in the Development of Latent Fingerprints;Trends in Analytical Chemistry, 1983, 2, 8, pp180-183.7. Lee, Henry C. and R.E. Gaensslen., eds.Advances in Fingerprint Technology. Boca Raton: CRC Press,

2001.

8. Hewlett, D. F.; Sears, V. G. Replacement for CFC113 in Ninhydrin Process,Journal of ForensicIdentification, 47(3), 1997, p287.

9. Horton, R. A. and Shaver, L. C., The Effects of Latent Print Processing on Ballpoint Pen Inks,AmericanSociety of Questioned Documents Examiners, 3(2) 2000, p70.

10. Watling, W. J. and Smith, K. O., Heptane, an Alternative to the Freon Ninhydrin Mixture,J. ForensicIdentification, 43(2) 1993, p. 131.

11. Wertheim, Pat A. Ninhydrin: Basic to Advanced, Forensic Identification Training Seminars, Ltd., IowaDivision for International Association for Identification, 2008;http://www.iowaiai.org/ninhydrin_basic_to_advanced.html

12. FBI Processing Guide for Developing Latent Print, 2000; http://onin.com/fp/fbi_2000_lp_guide.pdf
http://www.iowaiai.org/ninhydrin_basic_to_advanced.htmlhttp://www.iowaiai.org/ninhydrin_basic_to_advanced.htmlhttp://onin.com/fp/fbi_2000_lp_guide.pdfhttp://onin.com/fp/fbi_2000_lp_guide.pdfhttp://www.iowaiai.org/ninhydrin_basic_to_advanced.html


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4 Physical Developer

4 PHYSICAL DEVELOPER4.1 INTRODUCTION

Water soaked or wet papers rarely contain sufficient amounts of amino acids or salts for effective examinationwith normal porous surface processes. Components in sweat are either completely removed or diffused throughoutthe surface. Previous attempts to visualize latent prints on wetted porous items involved air drying and magneticpowder. Under optimum conditions when greasy or oily impressions remain on the surface and fiber swell doesnot create traps for overall painting, magnetic powder will adhere to the residue.

Physical developer is a product of British Home Office research devised specifically for the examination of wet orwater soaked porous items. This technique is a method which utilizes silver nitrate in an unstable ferrous/ferricredox solution in combination with a detergent solution. Unlike the conventional silver nitrate procedure whichreacts with the chlorides of palmar sweat, physical developer precipitates silver from the solution to any non-water soluble sebaceous material that is present in a latent print residue. Although this technique was developedfor water soaked items it can be used on any porous item, whether water soaked or not.

Since physical developer is an immersion process of high sensitivity, the reagent penetrates the porous material todetect any lipids which may be present. This reaction with residue other than palmar sweat increases theusefulness of physical developer as a post-treatment to items processed with ninhydrin and zinc chloride.However, physical developer cannot be used after the conventional silver nitrate procedure. Physical developer is

a somewhat complicated procedure when initially attempted, but can be efficiently incorporated as an examinationtechnique by batch processing eligible items.

Physical developer requires special care and exact adherence to procedures. All glassware and utensils must bededicated to the technique and reagent contamination must be avoided. In spite of these obstacles, the results oftenobtained from physical developer can be so productive that it must be included when full evidence exploration ofporous items is desired.

4.2 PREPARATIONS4.2.1 Stock Detergent Solution

1. If distilled water is not available deionized water may be used. Never use tap water for any of theworking solutions.

2. Pour one liter of distilled water into a large beaker containing a large magnetic stir bar previouslyrinsed with distilled water.

3. Add 2.7 grams of n-Dodecylamine Acetate and stir with a magnetic stirrer. If some of the detergentsticks to the weigh boat the weigh boat can be immersed in the solution.

4. Add 4 grams of Synperonic N, a surfactant. Place the weigh boat in the solution as the Synperonic Nwill adhere to the weigh boat.

5. Stir for thirty minutes.6. Remove the weigh boat(s).7. Pour the solution into a one liter glass bottle, transferring any material not yet dissolved. This

solution must not be used for at least 24 hours. At this time there should be no visible solids. If solidsare present, discard and remix.

*One liter of the stock detergent solution is sufficient to make 25 liters of Physical Developerworking solution. The Detergent Stock Solution has an indefinite shelf life.

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4.2.2 Maleic Acid Pre-wash1. Pour one liter of distilled water in a 1500 milliliter beaker.2. Add 25 grams of Maleic Acid and a large magnetic stir bar rinsed with distilled water.3. Stir with a magnetic stirrer until all solids are dissolved.

4.2.3 Silver Nitrate Solution1. Pour 50 milliliter of distilled water into a 100 milliliter beaker.2. Add 10 grams of silver nitrate and stir for one minute.3. Stir until dissolved.

4.2.4 Buffered Ferrous/Ferric Redox Solution1. Pour 900 milliliters of distilled water in a 1500 milliliter beaker.2. Rinse a large magnetic stir bar with distilled water and place in the beaker and stir.3. Add the following chemicals in the order given; making sure each chemical is dissolved before

adding the next chemical:

30 grams of Ferric Nitrate80 grams of Ferrous Ammonium Sulfate20 grams of Citric Acid

4. Stir until the Citric Acid is dissolved and then stir an additional five minutes.4.2.5 Combining the Component Solutions for Physical Developer

1. To the Redox Solution add 40 milliliters of the Stock Detergent Solution and stir.2. Examine the Silver Nitrate Solution to ensure that all solid material has dissolved. Stir again if

needed. Add the entire Silver Nitrate solution to the redox/detergent solution and stir for twominutes.

*Steps one and two must be performed in this order; otherwise the silver will fall out of suspension.

The Physical Developer is now ready for use. This prepares approximately one liter and should be sufficient toprocess about one hundred checks. The combined working solution is unstable and can not be stored and shouldtherefore be prepared on an as needed basis.

4.2.6 Polymax Fixer Rinses4.2.6.1 Rinse 1:

Add four or five drops of Polymax fixer per liter of tap water in a glass or plastic tray.

4.2.6.2 Rinse 2:Prepare a normal photofix solution with tap water in a glass or plastic tray (one part photographicfixer to nine parts tap water).

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4.2.7 Bleach SolutionPrepare the bleach solution by diluting household bleach at a ratio of 1:1 with tap water.

4.3 MINIMUM STANDARDS AND CONTROLSThe Positive Control for the Physical Developer Procedure consists of placing a test impression on a porous, non-evidentiary item, to a make test strip. The test strip is then immersed in the working solution. If the test impressionis visualized, the working solution can be used to process evidence. This testing procedure must be performed foreach working solution at the time the solution is made or used. Documentation of this process must be done in theform of a reagent log for each batch to include a batch number, established by month/day/year (060404). Ifadditional batches are made on the same day, add an alpha character to the batch number (060404a, b, c, etc.). Thebatch number must be placed on the original/working container. Documentation of this process must be includedin the examiners notes by indicating a positive reaction by placing a (+) adjacent to the procedure and byrecording the batch number. This test shall be performed for each case. Shelf life (working solution) shall notexceed thirty (30) days.

4.4 PROCEDURE OR ANALYSISThe procedure for Physical Developer involves three stages; a pre-wash, reagent development, and rinse. Sincethe working reagent is unstable, a pre-treatment wash is necessary, unless the items to be processed are too fragile,

to avoid the introduction of contaminants to the reagent. The rinse stage essentially removes contaminants andstabilizes the reaction.

All equipment associated with the pre-wash and reagent must be dedicated. Trays must be of glass and must bescrupulously clean. Beakers for mixing solutions should be labeled according to the type of solution and shouldnot be used for any other purpose. Plastic or bamboo tongs without serrated edges should be employed for itemhandling.

Rinse trays can be the plastic photographic type, but must be clean. Physical Developer reacts with even traceamounts of various rubber products so that rubber tipped tongs must not be used. Similarly, certain gloves willleave marks upon the evidence which will attract silver deposits. After the pre-wash any contact of glove tosurface must be avoided.

4.4.1 Step 1 - Maleic Acid Pre-wash1. Pour enough maleic acid pre-wash solution in a glass tray to cover the item to be processed.2. Immerse the item in the solution for five to ten minutes or until bubbles are no longer given off.

4.4.2 Step 2 - Physical Developer Solution1. Pour enough physical developer solution in a glass tray to cover the items to be processed.2. Drain the items of excess pre-wash.3. Immerse the items in the working solution and gently rock the tray.4. Keep the items separated and be careful not to crease or handle the items extensively.5. The processing time will vary and can be as little as one minute or up to twenty minutes. Therefore

the examiner should monitor the development very closely to avoid over processing and obliterationof weaker impressions. Remove the item when optimum contrast is observed.

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4.4.3 Step 3 - RinseTwo types of rinses are available. The items can be rinsed in a tray of tap water with a constant gentle flowof water into the tray or a two step photofix rinse can be employed.

4.4.3.1 Photofix Rinse1. After sufficient development in the physical developer solution the item is placed in the

first photofix rinse, standard photofix solution, for 30 seconds.

2. Transfer the item into the second photofix rinse (standard photofix solution) for threeminutes.

3. Wash the items in running tap water for three to five minutes.4.4.4 Step 4 - Drying

1. Allow the items to dry while lying flat. The items can be blotted carefully with blotter paper to speedthe drying process if the item is not fragile.

2. Impressions developed with physical developer are relatively stable.4.4.5 Step 5 - Bleach Solution (optional: to be used only when trying to improve the contrast of darker

impressions).

Only proceed with this step after all impressions developed previously have been photographicallypreserved.

1. Place the item in the bleach solution for two to three minutes.2. Rinse the item in running tap water for two to three minutes.

4.5 INTERPRETATION OF RESULTSProcessing of the porous items with physical developer is similar to photographic development. Latents appear asdark gray images which increase in contrast. The depletion of the working solution is unpredictable due to theinherent instability of the reagent. The failure to produce an image may be due to insufficient or no reactivematerial present in the item or exhaustion of the chemicals necessary to cause the reaction. Positive controls mustbe used with each run. Weaker impressions may benefit from additional processing with the physical developersolution. The item to be retreated should not be subjected to fixing with photographic fixer and/or bleaching asthese treatments will affect the success of the re-treatment.

Articles which appear too fragile for the maleic acid pre-wash, such as charred papers or extremely water soakeditems, may be introduced directly into the physical developer working solution. Such evidence should be treatedone item at a time and the solution must be checked carefully for the effects of contamination. Usuallycontamination will precipitate the silver from the working solution in the form of dark reddish brown particlesresembling curds. Contaminated solutions must be discarded and the evidence cannot be processed usingcontaminated solutions.

Photographic preservation of developed impressions which may be of value for individualization is essential andmust be accomplished as soon as possible.

4.6 REFERENCES1. Lee, Henry C.; Gaensslen, R. E., eds.Advances in Fingerprint Technology; Elsevier Science Publishers:

NY, 1991.

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2. Lennard, Christopher J.; Pierre A. Margot. Sequencing of Reagents for the Improved Visualization ofLatent Fingerprints;Journal of Forensic Identification, September/October 1988, 38, 5, 197-210.

3. Kent, Terry, ed. Fingerprint Development Techniques; Heanor Gate Publisher: Derbyshire, England, 1993.4. Phillips, Clarence E.; Douglass O. Cole; Gary W. Jones. Physical Developer: A Practical and Productive

Latent Print Developer;Journal of Forensic Identification, 1990, 40, 3, 135-147.
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5 Powders

5 POWDERS5.1 INTRODUCTION

Fingerprint powders are very fine particles with an affinity for moisture throughout a wide range of viscosity.Palmar sweat, grease, oil, and most contaminants that coat the surface of friction ridge skin possess sufficientmoisture and viscosity to attract and bind the fine particles together. Contact between friction ridge skin and anon-porous surface will sometimes result in a transfer of the skin coating to that surface. The non-absorbency ofthe surface prevents penetration by the deposited moisture. All fingerprint powders are indiscriminate in adhesionto moisture. Surfaces coated with residue in addition to suspected latent prints will attract powders all over thesurface

Dependent upon the composition of the residue, the deposited moisture will range from a most apparentappearance to the barely perceptible or invisible, even under oblique lighting. Powder application is the effort toproduce or improve the appearance for preservation.

The most effective agent in terms of adherence to moisture, non-adherence to dry surfaces, particle size, shape,uniformity, and intensity of color is carbon. Carbon is black, and as a result, black powders which contain carbonwill consistently produce the best results. Most commercial black fingerprint powders have a high carbon base.According to the manufacturer's particular formula and production methods, the carbon base may be from avariety of sources, including lamp black, bone, or wood charcoal. Commercial powders contain milled carbon of

highly uniform size and shape along with additional ingredients to preserve the milled condition and retardmoisture absorption. Other colored powders may be required due to the substrate encountered, but should berestricted to absolute necessity.

Magnetic powders are powder-coated, fine iron filings subject to magnetic attraction. These adhere to moisture toa lesser degree than carbon powders, but can be applied with less destructive force to the surface.

Redwop fluorescent powders have a lycopodium base and were developed specifically to be luminescent - excitedby light sources emitting blue-green light. Redwop fluorescent powder is recommended as a primary usefluorescent powder for examination of latent prints with forensic light sources and ultraviolet light sources.

5.2 PREPARATIONSNo specific preparations are needed as the powders and materials being used are commercially prepared.

5.3 INSTRUMENTATIONSee Appendix III-General Instrumentation.

5.4 MINIMUM STANDARDS AND CONTROLSThe Standards and Controls for the Powders consist of insuring that the powders being used are in the propercondition. Powders should not be exposed to high humidity or moisture. Powders may clump if exposed toexcessive moisture or contaminants. Moisture content and contaminants may be minimized by keeping the stockcontainer closed as much as possible and using containers with small amounts of powder. This will minimize themoisture content as well as reduce any contamination of the stock container with substances from the item beingprocessed. The date the container is opened is to be used as the batch number, established by month/day/year(060404). If additional containers are opened on the same day, add an alpha character to the batch number(060404a, b, c, etc.). The batch number shall be placed on the original and working container and in theexaminers notes. Shelf life is indeterminable; however, if clumping of the powder is observed, it shall bediscarded.

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5 Powders

5.5 PROCEDURE OR ANALYSIS5.5.1 Standard Powders

Powders may be applied by various means, but the preferred procedure for most items is the use of a brush.Fiberglass brushes are the easiest to use and maintain while permitting application over a wider area.Powders are more effective if applied in very small amounts. While some examiners prefer pouring asupply of powder into a secondary container or a piece of paper, direct contact between brush and powdercontainer is acceptable. Only the ends of the brush bristles should be coated with the powder, and the brushshould be gently tapped several times to remove all but a minimum amount.

With the brush handle in a nearly perpendicular position to the surface, the bristle ends are lightly anddelicately moved over the surface. Discoloration of the latent print residue will usually appear immediately.With a fiberglass brush and a proper amount of powder, the impression will develop in density with eachlight pass until no further development can be observed. Even slightly excessive amounts of powder willcause a fill to occur between ridges. This fill must be removed with continued brush strokes until theimpression is as free of extraneous powder as possible. Except on highly polished surfaces, excessivebrushing is rare with a fiberglass brush. However, at the first indication that the impression is beingremoved, all further brushing must cease.

Extraneous residue on the surface may cause a general painting effect which obscures friction ridge detail.

A lift made of the area can sometimes remove the extraneous material and permit a second application ofpowder. This second application may offer better contrast between latent print deposit and the background.

5.5.2 Magnetic PowdersMagnetic powder must be applied with a magnetic application device. Wands which contain a movablemagnet attract the powder when the magnet is depressed and release the powder when it is raised. Contactbetween powder and surface is completed without bristles and is more light and delicate than the fiberglassbrush. However, the particle size, larger than standard powder, has a tendency to paint some surfaces.Excessive powder can sometimes be removed by passing the magnetic wand without powder near thesurface. Since the magnetic attraction holding the iron particles is relatively weak, the supply can bedepleted quickly. Surface areas examined generally must be processed more slowly with magneticpowders, and great care must be exercised to prevent actual contact between the end of the wand and the

surface.

5.5.3 Redwop PowderRedwop powders are applied in the same manner as standard powders. It is not recommended to make a liftof the latent print but view with a light source. If lifting is desired, process with black powder and then lift.

5.6 INTERPRETATION OF RESULTSPowder developed latent impressions which may be of value for individualization must be properly preserved.Experiments have revealed that the developed latent impressions have a weaker adhesion to the surface thanundeveloped, and, as a result, are more susceptible to damage from accidental contact. Two methods ofpreservation are normally afforded the powder developed latent: photography and lifting.

Photographic preservation of developed impressions which may be of value for individualization is essential andmust be accomplished as soon as possible. Lifting is also an approved procedure but caution should be taken whenlifting to insure that the lift will be successful. If the lift can not be made with confidence that it will be successful,the developed fiction ridge detail should be photographed prior to lifting.

5.7 REFERENCES1. Cowger, James F. Friction Ridge Skin Comparison and Identification of Fingerprints; Boca Raton: CRC

Press, 1993.

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2. Lee, Henry C.; Gaensslen, R. E., eds.Advances in Fingerprint Technology; Elsevier Science Publishers,NY, 1991.

3. Olson, Robert. Scotts Fingerprint Mechanics; Charles C. Thomas Publisher: Springfield, IL, 1978.4. Waldoch, Terry L. The Flame Method of Soot Deposition for the Development of Latent Prints on Non-

porous Surfaces;Journal of Forensic Identification, 1993, 43, 5, 463-465.
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6 Small Particle Reagent

6 SMALL PARTICLE REAGENT6.1 INTRODUCTION

Small particle reagent (SPR) was devised and refined by the British Home Office as an effective procedure forprocessing wet surfaces. Surfaces, both porous and nonporous, which are wet at the time of latent print deposit orbecome wet after deposit, seldom retain sufficient water soluble material for conventional processing methods.Nonporous items which have been allowed to dry offer some potential if the deposit contains non-water solubleoily matter, but the drying process lessens the possibility of adequate adhesion for powders.

Molybdenum disulfide is a lipid-sensitive reagent. Initial efforts to create a suspension of molybdenum disulfidein water used photoflo as a means of reducing surface tension. These met with limited success. Introduction ofphotoflo to the mixture requires a critical measurement as too much photoflo prevents complete adhesion of themolybdenum disulfide particles to the lipids. Organic solvents can not be used as these solvents may remove thelipid material.

Refinements in the surfactant solution have not only improved the uniformity of suspension but have increased theapplication of SPR to other surfaces. SPR is very effective in the secondary treatment of cyanoacrylate esterdeveloped impressions by adhering to faint impressions generally better than powders. Molybdenum disulfide isproduced in various particle sizes. Smaller particle size is more effective: Lightning Powder Company providesthe proper particle size. If distilled water is not available deionized water may be used.

6.2 PREPARATIONS6.2.1 Surfactant Stock Solution

Dissolve 8 milliliters of Tergitol 7 in 500 milliliters of distilled water. This will make approximately 10liters of working solution.

6.2.2 SPR Suspension - Working Solution1. Add 10 grams of molybdenum disulfide to 50 milliliters of the surfactant stock solution. Add the

molybdenum disulfide slowly and stir continuously.

2. The mixture should be a creamy consistency free of any dry powder.3. While stirring continuously, add the mixture to 900 milliliters of distilled water.

6.3 MINIMUM STANDARDS AND CONTROLSMolybdenum disulfide works by adhering to latent print residue. Place a latent print on a non-evidentiary item andprocess with the SPR as described in 6.4.1 and 6.4.2. This testing procedure must be performed for each workingsolution at the time the solution is made or when a commercially purchased bottle is opened. Documentation ofthis process must be done in the form of a reagent log for each batch to include a batch number, established bymonth/day/year (060404). If additional batches are made on the same day, add an alpha character to the batchnumber (060404a, b, c, etc.). The batch number must be placed on the original/working container. Documentationof this process must be included in the examiners notes by indicating a positive reaction by placing a (+) adjacentto the procedure and by recording the batch number. This test shall be performed for each case. Shelf life shouldnot exceed one year.

6.4 PROCEDURE OR ANALYSIS6.4.1 Immersion Technique

1. Shake the working solution well and place in a shallow tray such as a photographic tray. The trayshould be filled until it will cover the item to be processed.

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2. Stir the solution again and before each item is placed into the solution.3. Place the item to be processed in the liquid to lie as flat as possible in the tray.4. Allow the item to remain in the suspension and the molybdenum particles to settle on the item for

approximately 30 seconds.

5. The item is then turned over and again allowed to set for approximately 30 seconds.6. This procedure is continued until all surfaces have been exposed to the solution.7. The item is then placed into a tray of clear tap water. The tray can be rocked or a flow of tap water

can be established in the tray. The excess SPR will readily be removed.

8. The item is allowed to dry.6.4.2 Wash Bottle Application

1. Spray a flow of SPR over the surface of the item.2. Wash the surface with a light to moderate flow of clear tap water.

Larger items may be processed using a wash bottle to spray a flow of SPR over the surface. For outdoorapplication of very large items, such as a wet automobile, a garden sprayer can be used. Generally light tomoderate flows of rinse water will not dislodge the molybdenum disulfide particles.

6.5 INTERPRETATION OF RESULTSPhotographic preservation of developed impressions which may be of value for individualization is essential andmust be accomplished as soon as possible.

SPR lifts easily from dried, processed, nonporous surfaces. Faint impressions may benefit from a reprocessing ofthe item. The intense black color generally facilitates photographic preservation. When SPR is used as asecondary technique after cyanoacrylate ester fuming, the results are sometimes superior to powders in both

adhesion and clarity of detail.

6.6 REFERENCES1. Lee, Henry C.; Gaensslen, R. E., eds.Advances in Fingerprint Technology; Elsevier Science Publishers,

NY, 1991.

2. Onstwedder, John III; Thomas E. Gamboe. Small Particle Reagent: Developing Latent Prints on Water-Soaked Firearms and Effect on Firearms Analysis;Journal of Forensic Sciences, 1989, 34, 2, 321-327.

3. Pounds, C.A.; R.J. Jones. Physicochemical Techniques in the Development of Latent Fingerprints;Trends in Analytical Chemistry,1983, 2, 8, 180-183.
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7 Cyanoacrylate Ester Fuming

7 CYANOACRYLATE ESTER FUMING7.1 INTRODUCTION

Cyanoacrylate esters are the active ingredients in the super bond adhesives and are generally available accordingto the type of alcohols used in manufacturing. Most cyanoacrylates are methyl or ethyl esters. Regardless of type,the esters volatilize into long chain molecules with a positive electrical charge. In an atmosphere of relatively highhumidity, the cyanoacrylate ester molecules are attracted to fingerprint residue and polymerize upon the deposit.

Properties of the polymer are dependent upon the type of cyanoacrylate ester used. Both ethyl and methyl estersproduce a visible white coating. Ethyl ester polymers are softer and less durable while methyl ester polymers canusually only be removed with solvents. However, the durable, hard property of the methyl ester appears to inhibitdye applications.

Locktite and other brand name products contain a cyanoacrylate ethyl ester and have proven to be quite effectivefor fuming. Locktite 495 Super Bonder provides a liquid useful for heat acceleration techniques while HardEvidence is a gel which reacts to exposure to air. Any product containing ethyl ester generally will be moreeffective when subsequent laser dye applications are indicated. Cyanoacrylate ester fuming is highly effectivewith nonporous items made of plastics or metal. It is superior to any other method for the processing of gun metal.

7.2 PREPARATIONSNo specific preparations are needed as the cyanoacrylate materials being used are commercially prepared.

7.3 INSTRUMENTATIONCyanoacrylate Fuming Chambers, Atmospheric and Vacuum

7.4 MINIMUM STANDARDS & CONTROLSThe Standards and Controls for cyanoacrylate ester fuming procedure require the use of test impressions. Non-evidentiary items such as aluminum foil, film leaders or pieces of plastic bags are convenient substrates whendeliberately deposited with a test impression and placed near the evidence. Processing should be terminated whentest impressions have reached optimum development. However, all items should be watched carefully as faster or

slower development may occur. Exposure of surfaces to a high concentration of fumes can result inoverdevelopment which obscures impressions due to total surface polymerization. The batch number forcyanoacrylate ester will be established by the date opened, such as (060404). If additional bottles are opened onthe same day, add an alpha character to the batch number (060404a, b, c, etc.). The batch number must be placedon the working container. Documentation of this process must be included in the examiners notes by indicating apositive reaction by placing a (+) adjacent to the procedure and by recording the batch number. This test shall beperformed for each case. The shelf life is indeterminable and may be used as long as it remains in a semi-liquidstate and has a positive reaction with the test strip.

7.5 ATMOSPHERIC CHAMBERVolatilization of cyanoacrylate ester at normal room temperature is relatively slow but is a viable procedure forevidence processing. Vapors must be contained, and a tank or plastic enclosure is most often used. A ratio of twodrops of adhesive for every gallon of capacity or volume with relatively high humidity is usually effective.Polymerization may be retarded or prevented by low humidity. The addition of a cup of lukewarm water usuallywill improve the fuming results. Development time will vary with the temperature, humidity and the substratebeing processed.

Application of heat greatly accelerates volatilization. Metal blocks or a hot plate can serve as the heat source butcaution must be used not to over heat to the point where cyanide vapors can be produced. An aluminum dish orshaped foil may be placed on the hot surface and the adhesive poured onto the aluminum. A cup of warm water isplaced in the enclosure. Volatilization can be very rapid and development may be accomplished. Care must betaken to closely observe the process to insure that the item is not overdeveloped.

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7 Cyanoacrylate Ester Fuming


An alternative, which offers rapid development time with minimum health risk, is to use a light bulb as the heatsource. A standard light receptacle is added to the processing tank with a wire loop support fashioned to hold awatch glass approximately 1 inch above the light bulb. The adhesive is dropped onto the watch glass. A cup ofwarm water is placed in the enclosure if additional humidity is needed. Once the container is covered tightly, thelight is turned on. Rapid volatilization does not begin until the heat from the bulb penetrates the watch glass.Natural convection currents aid dispersal of the fumes and development is generally accomplished in about 15minutes.

A convenient and effective method is the use of an exclusive product, Locktite Hard Evidence. Cyanoacrylateesters are mixed in a gel with chemicals that produce fairly rapid but controlled volatilization upon exposure toair. The product is available in pouches which are easily peeled open to commence the volatilization, but whichcan be resealed to stop the reaction. Each pouch will produce fumes for ten to fifteen hours dependent uponambient temperature; however, volatilization slows with exposure so that more time must be allowed for pouchesapproaching exhaustion. Hard Evidence does have a shorter shelf life than liquid cyanoacrylate ester compounds.Pouches anticipated to be stored for longer than six months should be refrigerated but not frozen, and allowed toreach room temperature before use. However, previously opened pouches should not be refrigerated. Openedpouches which may not be used again for some time should additionally be sealed with tape to prevent gradualrelease of fumes.

7.6 VACUUM CHAMBERA vacuum chamber using humidity and cyanoacrylate vapors @37C is a highly sensitive system to developfingerprints on the inside of polyethylene bags, hand guns, long guns, gas cans, etc. Vacuum chambers areparticularly effective on evidence that has a soot or oil film on the surface. Incubating dry fingerprints prior to CAfuming enhances the ridge detail.

7.7 INTERPRETATION OF RESULTSPhotographic preservation of developed impressions which may be of value for individualization is essential andmust be accomplished as soon as possible. Once the latent impressions are recorded, further processing sometimesreveals impressions in which polymerization was too indistinct for visual notice or did not occur. Powders andparticulate developers are effective and often permit additional photographic and lifting preservation. Smallparticle reagent will sometimes adhere to faint impressions when powders will not. Laser dye application isgenerally effective after powder, particulate, or SPR application as the liquid dye solution will normally wash

away the particulate remnants. However, vinyl, rubber, oily guns, and hard plastics, especially those used in cashregister drawers, may not be receptive to any powder.

7.8 REFERENCES1. Lee, Henry C.; R. E. Gaensslen. Cyanoacrylate Fuming;Identification News, 1984, 34, 3, 8-14.2. Lee, Henry C.; Gaensslen, R. E., eds.Advances in Fingerprint Technology; Elsevier Science Publishers,

NY, 1991.

3. Lennard, Christopher J.; Pierre A. Margot. Sequencing of Reagents for the Improved Visualization ofLatent Fingerprints;Journal of Forensic Identification, September/October 1988, 38, 5, 197-210.

4. Kent, Terry, ed. Fingerprint Development Techniques; Heanor Gate Publisher: Derbyshire, England, 1993.5. Pounds, C.A.; R.J. Jones. Physicochemical Techniques in the Development of Latent Fingerprints;

Trends in Analytical Chemistry, 1983, 2, 8, 180-183.
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8 Dye Stains

8 DYE STAINS8.1 INTRODUCTION

Dye staining was developed as a means of enhancing cyanoacrylate ester polymerized impressions. The dye stainis applied to a non-porous item that has been subjected to cyanoacrylate ester fumes. The dye stain is applied tothe object and visually examined utilizing an alternate light source. The application of the dye stain enhances thelatent developed with cyanoacrylate ester fumes to allow for visualization and photography. Each dye stain listedbelow will have different preparation steps and optimum viewing parameters.

8.2 PREPARATIONS8.2.1 Ardrox

Ardrox is commercially available; no preparation is needed for the undiluted application. The properties ofArdrox are highly complementary to the cyanoacrylate ester process, and may yield results that equal orsurpass those of the Rhodamine 6G procedure. However, instances have occurred when Rhodamine 6Grevealed impressions that were not stained by Ardrox P133D with UV excitation. This lack of consistencycurrently delegates Ardrox P133D as an additional processing technique, not as a replacement for dye andALS examination.

Ardrox P133D is also luminescent at 470. However, since the two procedures are compatible, use ofArdrox staining as an additional technique to be utilized in conjunction with the ALS dyes, wheneverpossible, is recommended.

Chemical Formula

Combine ingredients in the order listed.

2 ml Ardrox 10 ml Acetone 25 ml Methanol 10 ml Isopropyl alcohol 8 ml Acetonitrile 945 ml Petroleum ether

8.2.2 Basic Yellow 40Basic Yellow 40 is a commercially available powder that is mixed with a solvent to create a workingsolution. Basic Yellow 40 fluoresces between 365 nm and 485 nm.

Chemical Formula

3 grams of Basic Yellow powder concentrate 1000 ml of methanolCombine the ingredients and continue to stir the solution until all of the powder is dissolved.