1、Designation: E1610 17Standard Guide forForensic Paint Analysis and Comparison1This standard is issued under the fixed designation E1610; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenth
2、eses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 Forensic paint analyses and comparisons are typicallydistinguished by sample size that precludes the application ofmany standard industrial paint analys
3、is procedures or proto-cols. The forensic paint examiner must address concerns suchas the issues of a case or investigation, sample size, complexityand condition, environmental effects, and collection methods.These factors require that the forensic paint examiner choosetest methods, sample preparati
4、on schemes, test sequence, anddegree of sample alteration and consumption that are suitableto each specific case.1.2 This guide is intended as an introduction to standardguides for forensic examination of paints and coatings. It isintended to assist individuals who conduct forensic paintanalyses in
5、their evaluation, selection, and application of teststhat may be of value to their investigations. This guidedescribes methods to develop discriminatory information usingan efficient and reasonable order of testing. The need forvalidated methods and quality assurance guidelines is alsoaddressed. Thi
6、s document is not intended as a detailed methodsdescription or rigid scheme for the analysis and comparison ofpaints, but as a guide to the strengths and limitations of eachanalytical method. The goal is to provide a consistent approachto forensic paint analysis.1.3 This guide cannot replace knowled
7、ge, skill, or abilityacquired through appropriate education, training, and experi-ence and should be used in conjunction with sound profes-sional judgment.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 Some of the metho
8、ds discussed in this guide involve theuse of dangerous chemicals, temperatures, and radiationsources. This guide does not purport to address the possiblesafety hazards or precautions associated with its application.This standard does not purport to address all of the safetyconcerns, if any, associat
9、ed with its use. It is the responsibilityof the user of this standard to establish appropriate safety,health, and environmental practices and determine the appli-cability of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with internationally recogniz
10、ed principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D16 Terminology for Pain
11、t, Related Coatings, Materials, andApplicationsD1535 Practice for Specifying Color by the Munsell SystemE308 Practice for Computing the Colors of Objects by Usingthe CIE SystemE1492 Practice for Receiving, Documenting, Storing, andRetrieving Evidence in a Forensic Science LaboratoryE2808 Guide for M
12、icrospectrophotometry and Color Mea-surement in Forensic Paint AnalysisE2809 Guide for Using Scanning Electron Microscopy/X-Ray Spectrometry in Forensic Paint ExaminationsE2937 Guide for Using Infrared Spectroscopy in ForensicPaint Examinations3. Terminology3.1 DefinitionsFor definitions of terms us
13、ed in this guideother than those listed in 3.2, see Terminology D16.3.2 Definitions of Terms Specific to This Standard:3.2.1 additive (modifier)any substance added in a smallquantity to improve properties. Additives may include sub-stances such as driers, corrosion inhibitors, catalysts, ultravio-le
14、t absorbers, plasticizers, etc.3.2.2 bindera non-volatile portion of a paint which servesto bind or cement the pigment particles together.1This guide is under the jurisdiction of ASTM Committee E30 on ForensicSciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics.Current
15、edition approved Sept. 1, 2017. Published September 2017. Originallyapproved in 1994. Last previous edition approved in 2014 as E1610 14. DOI:10.1520/E1610-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of
16、ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized p
17、rinciples on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.3 coatinga generic term for paint, lacquer, enamel, orother liquid
18、or liquifiable material which is converted to asolid, protective, decorative, or combination thereof, film afterapplication.3.2.4 discriminateto distinguish between two samplesbased on significant differences; to differentiate.3.2.5 discriminating powerthe ability of an analyticalprocedure to distin
19、guish between two items of different origin.3.2.6 known samplea coating sample of established ori-gin.3.2.7 paintcommonly known as a pigmented coating (see3.2.3).3.2.8 pigmenta finely ground, inorganic or organic,insoluble, dispersed particle. Besides color, a pigment mayprovide many of the essentia
20、l properties of paint, such asopacity, hardness, durability and corrosion resistance. The termpigment includes extenders.3.2.9 questioned samplea coating sample whose originalsource is unknown.3.2.10 significant differencea difference between twosamples that indicates that the two samples do not hav
21、e acommon origin.4. Quality Assurance Considerations4.1 Aquality assurance program must be used to ensure thatanalytical testing procedures and reporting of results aremonitored by means of proficiency tests and technical audits.General quality assurance guidelines may be found in “TraceEvidence Qua
22、lity Assurance Guidelines” (1).35. Summary of Practice5.1 Paint films are characterized by a number of physicaland chemical features. The physical characteristics may in-clude color, layer sequence and thickness, surface and layerfeatures, contaminants and weathering. Chemical componentsmay include
23、pigments, polymers, additives and solvents. Thesefeatures can be determined and evaluated by a variety ofmacroscopical, microscopical, chemical, and instrumentalmethods. Limited sample size and sample preservation require-ments mandate that these methods be selected and applied in areasonable sequen
24、ce to maximize the discriminating power ofthe analytical scheme.5.2 Searching for differences between questioned andknown samples is the basic thrust of forensic paint analysis andcomparison. However, differences in appearance, layersequence, size, shape, thickness, or some other physical orchemical
25、 feature can exist even in samples that are known to befrom the same source. A forensic paint examiners goal is toassess the significance of any observed differences. The ab-sence of significant differences at the conclusion of an analysissuggests that the paint samples could have a common origin.Th
26、e strength of such an interpretation is a function of the typeor number of corresponding features, or both.5.3 An important aspect of forensic automotive paint analy-sis is the identification of the possible makes, models and yearsof manufacture of motor vehicles from paint collected at thescene of
27、a crime or accident. The color comparison andchemical analysis of both the undercoat and top coat systemsrequires knowledge of paint formulations and processes, col-lections of paint standards, and databases of color and compo-sitional information.5.4 The test procedure selected in a paint analysis
28、andcomparison begins with thorough sample documentation.Some features of that documentation are described in PracticeE1492.Analysis generally begins with appropriate nondestruc-tive tests. If these initial tests are inconclusive or notexclusionary, the examination may proceed with the selectionof ad
29、ditional tests based on their potential for use in evaluatingor discriminating the samples of interest, or both.6. Significance and Use6.1 This guide is designed to assist the forensic paintexaminer in selecting and organizing an analytical scheme foridentifying and comparing paints and coatings. Th
30、e size andcondition of the sample(s) will influence the selected analyticalscheme.7. Collection of Suitable Samples7.1 The potential for physical matches between known andquestioned samples must be considered before selecting themethod of paint sample collection. Care should be taken topreserve the
31、potential for a physical match.7.2 Questioned Samples:7.2.1 Questioned samples should include all loose or trans-ferred paint materials. Sources of questioned samples caninclude tools, floors, walls, glass fragments, hair, fingernails,roadways, adjacent structures, transfers or smears on vehicles,or
32、 transfers to or from individuals such as damaged fabric withpaint inclusions. Whenever possible, items with paint transfersshould be appropriately packaged and submitted in theirentirety for examination. If sampling is necessary, the proce-dures listed in “Trace Evidence Recovery Guidelines” (2) ma
33、ybe used. When paint evidence is recognized, every effortshould be made to manually remove it before using tape lifts tocollect other types of evidence. If paint is collected with tapelifts, one should be aware of the possible difficulty encounteredwhen attempting to manipulate paint samples bearing
34、 adhesiveresidues. In addition, components of the adhesive could con-taminate the paint sample and change its apparent chemistry.7.2.2 Smeared transfers can exhibit mingling of componentsfrom several layers or films that could preclude application ofsome of the analytical methods discussed in this g
35、uide. Due tothe difficulties associated with collecting smeared or abradedsamples, the entire object bearing the questioned paint shouldbe submitted to the laboratory whenever possible.7.2.3 When contact between two coated surfaces isindicated, the possibility of cross-transfers must be considered.T
36、herefore, if available, samples from both surfaces should becollected.3The boldface numbers in parentheses refer to the list of references at the end ofthis standard.E1610 1727.3 Known Samples:7.3.1 When feasible, known paint samples should be col-lected from areas as close as possible to, but not w
37、ithin, thepoint(s) of damage or transfer. Due to the possible presence ofcross transferred materials, these damaged areas are usually notsuitable sources of known samples. The collected knownsamples should contain all layers of the undamaged paint film.Substantial variations in thickness and layer s
38、equences overshort distances can exist across a painted surface. This isparticularly true in architectural paint and for automotive filmswhere the curves, corners, and edges are often impact pointsand may have been subjected to previous damage, sanding orover-painting. If necessary, several known pa
39、int samplesshould be taken to properly represent all damaged areasbecause different areas of the painted surface may containdifferent paint systems. Known paint samples collected fromdifferent areas should be packaged separately and labeledappropriately.7.3.2 When possible, the surface underlying th
40、e suspectedtransfer area should be included for analysis. Sections adjacentto a suspect transfer area can be valuable for assessingquestioned and known sample differences and evaluating thepossible cross transfer of trace materials.Wall and ceiling, doorand window, implement handle and automobile do
41、or, fenderand hood are examples of adjacent items.7.3.3 Paint flakes can be removed from the parent surface bya number of methods. These include, but are not limited to,lifting or prying loosely attached flakes, cutting samples of theentire paint layer structure using a clean knife or blade, ordislo
42、dging by gently impacting the opposite side of the paintedsurface. When cutting, it is important that the blade be inserteddown to the parent surface. It should be noted that no onemethod of sampling should be relied upon exclusively.8. Procedure8.1 Discussions of forensic paint analysis are provide
43、d indated but detailed form by Crown (3), and more recently byNielsen (4), Thornton (5), Maehly and Strmberg (6), Stoeck-lein (7), Caddy (8), and Ryland and Suzuki (9).8.2 A reasonable scheme for forensic paint examinations isoutlined in Figs. 1-4. Potentially useful techniques for thediscrimination
44、 of paint binders, pigments, and additives arelisted. For any given comparison, not all the techniques listedin the same area in Fig. 1 are necessarily required. Sample size,condition and layer structure complexity should be consideredwhen determining which techniques to use. The forensiccoatings ex
45、aminer should always use the more specific andleast destructive tests prior to those that require more samplepreparation or consumption. A review of the general techniquedescriptions, listed in 8.8 8.15, will provide guidance for theselection of appropriate methods.8.3 Fig. 1 does not imply that oth
46、er examinations should beexcluded or that the order of the procedures in the chart isirrevocable. Samples that are neither constrained by amountnor condition should be subjected to analyses that will deter-mine the color and texture of the paint as well as the number,order, colors and textures of th
47、e layers in a multi-layeredsample. In most cases, instrumental techniques should beemployed to analyze and compare both the pigment and binderportions of the sample. A combination of techniques, whichprovide discrimination between as many types of paints andcoatings as possible, should be used. Thes
48、e techniques shouldalso be selected to provide classification or component identi-fication information, or both, to be used in significanceassessments. For samples that are limited in layer structurecomplexity, techniques for the comparison of both the binderand pigment portion of the coating must b
49、e used. The choice oftechniques can change depending upon sample characteristics.For instance, pyrolysis-gas chromatography (PGC) may beutilized for identifying and comparing the binder portion ofsamples that exhibit a low binder concentration. Likewise,scanning electron microscopy-energy dispersive X-ray analysis(SEM-EDS), X-ray fluorescence (XRF) and X-ray diffraction(XRD) may be used for identifying and comparing the pigmentportion of samples that exhibit a low pigment concentration.8.4 The flow-chart in Fig. 5 is a guide to the determinationof the possible origins
