\ LIBRARY Michigan State 52 Cox; University ( Mic-"NO This is to certify that the thesis entitled COLOR ANALYSIS OF APPARENTLY ACHROMATIC AUTOMOTIVE PAINTS BY VISIBLE MICROSPECTROPHOTOMETRY presented by Kristin A. Kopchick has been accepted towards fulfillment of the requirements for the MS. degree in Forensic Science WM / U Majo‘r'Profis' or’s Signature 7 I /,L/ 0 9 Date MSU is an Affirmative Action/Equal Opportunity Institution PLACE IN RETURN BOX to remove this checkout from your record. TO AVOID FINES return on or before date due. MAY BE RECALLED with earlier due date if requested. DATE DUE DATE DUE DATE DUE 2/05 c:/ClRC/DateDue.indd-p. 15 COLOR ANALYSIS OF APPARENTLY ACHROMATIC AUTOMOTIVE PAINTS BY VISIBLE MICROSPECTROPHOTOMETRY' By Kristin A. Kopchick A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Criminal Justice 2005 ABSTRACT COLOR ANALYSIS OF APPARENTLY ACHROMATIC AUTOMOTIVE PAINTS BY VISIBLE MICROSPECTROPHOTOMETRY By Kristin A. Kopchick Chromatic secondary pigments are utilized in achromatic automotive paints to create unique paint systems. Achromatic paints are considered to lack color and include white, black, and shades of gray. The chromatic pigments that add an intended color effect may not be observable in reflected light; however, utilizing visible microspectro- photometry (MSP) discriminating data may be gathered. This study analyzed 160 apparently achromatic automotive paints via this technique for spectral evidence of chromatic secondary pigmentation. Positive spectral results were attained in the black and gray/silver topcoat sample set while the white topcoat and gray undercoat set yielded no spectral data. The data suggests that paint analysis schemes should incorporate visible microspectrophotometry for black and gray/silver samples. ACKNOWLEDGEMENTS The author would like to thank Dr. Jay A. Siegel for support and guidance and the committee for this thesis including Roger Bolhouse and Dr. Christina DeJong. A large part of this research was made possible by Christopher R. Bommarito of the Michigan State police and the Lansing Crime Laboratory. Many thanks go to Mr. Bommarito for his expertise and continued guidance with this project. Instrumental assistance and advice was provided by Dr. Paul Martin of CRAIC Technologies. Additional thanks to Dr. Edmund McGarrell and the Michigan State University School of Criminal Justice for support and facilities. Automotive samples were gathered from A.G. Birrell Co. of Kinsman, Ohio, Barnum and Tenny Body Shop of East Lansing, Michigan, and Shroyer Auto Parts of Lansing, Michigan. iii TABLE OF CONTENTS LIST OF TABLES ............................................................................................................ v LIST OF FIGURES ........................................................................................................... vi INTRODUCTION ............................................................................................................. 1 THESIS ............................................................................................................................. 5 Methods ....................................................................................... ' .......................... 5 Results and Discussion .......................................................................................... 7 Conclusions ........................................................................................................... 13 Future Work .......................................................................................................... 16 APPENDICES ................................................................................................................... 1 8 Appendix A - Vehicle collection data ................................................................... 19 Appendix B - Microscopy data ............................................................................. 27 Appendix C - Visible MSP spectra ....................................................................... 32 REFERENCES ...................................................................... 54 iv LIST OF TABLES Table 1: Vehicle totals by manufacturer and production date ............................................. 6 Table 2: Vehicle Data of all Samples Collected ................................................................ 20 Table 3: Polarizing Light Microscopy Data ............................................ ' ........................... 27 LIST OF FIGURES Figure l: Absorbances in the visible spectrum may be the result of colored binders or pigments which may or may not be visible in reflected light. A: 1996 Ford Explorer where no pigments were visible via PLM, B: 1999 Mercury Sable with tinted binder, C: 1996 Oldsmobile Cutlass where pigments were visible via PLM ....................................... 8 Figure 2: Spectra A and B represent gray samples which displayed strong absorbances throughout the visible region due to colored binders. Spectrum C with weaker absorbances at 525 and 575nm is consistent with gray samples with pigments visible via PLM. A: 2002 Honda Odyssey, B: 2004 Saturn Ion, C: 1996 Oldsmobile Cutlass ............ 9 Figure 3: Five analyses from sample B34 taken from different locations. B34: 1993 BMW 318i ......................................................................................................................... 11 Figure 4: Visible Microspectrophotometry spectrum of sample B6 .................................. 33 Figure 5: Visible Microspectrophotometry spectrum of sample B7 .................................. 34 Figure 6: Visible Microspectrophotometry spectrum of sample B10 ................................ 35 Figure 7: Visible Microspectrophotometry spectrum of sample B14 ................................ 36 Figure 8: Visible Microspectrophotometry spectrum of sample B23 ................................ 37 Figure 9: Visible Microspectrophotometry spectrum of sample B23 ................................ 38 Figure 10: Visible Microspectrophotometry spectrum of sample 326 .............................. 39 Figure 11: Visible Microspectrophotometry spectrum of sample 828 .............................. 40 Figure 12: Visible Microspectrophotometry spectrum of sample B30 .............................. 41 Figure 13: Visible Microspectrophotometry spectrum of sample B34 .............................. 42 Figure 14: Visible Microspectrophotometry spectrum of sample B38 .............................. 43 Figure 15: Visible Microspectrophotometry spectrum of sample G4 ............................... 44 Figure 16: Visible Microspectrophotometry spectrum of sample G12 ............................. 45 Figure 17: Visible Microspectrophotometry spectrum of sample G14 ............................. 46 Figure 18: Visible Microspectrophotometry spectrum of sample 619 ............................. 47 vi Figure 19: Visible Microspectrophotometry spectrum of sample G20 ............................. 48 Figure 20: Visible Microspectrophotometry spectrum of sample G32 ............................. 49 Figure 21: Visible Microspectrophotometry spectrum of sample G33 ............................. 50 Figure 22: Visible Microspectrophotometry spectrum of sample G39 ............................. 51 Figure 23: Visible Microspectrophotometry spectrum of sample G40... .......................... 52 Figure 24: Visible Microspectrophotometry spectrum of sample G45 ............................. 53 vii Introduction Color analysis is a valuable aspect of any paint comparison performed in a forensic setting. The American Society for Testing and Materials (ASTM) and the Scientific Working Group on Materials Analysis (SWGMAT) recognize the importance of this element and outline guidelines for consistent definition and comparison of color. Different techniques have been developed to provide information on color including visible microspectrophotometry (MSP) which allows discrimination of samples by their interaction with light in the visible region of the electromagnetic spectrum. Both ASTM and SWGMAT have recommended absorption spectrophotometry as discriminating techniques for paint color (1,2). As light strikes a paint coating, some wavelengths will be absorbed based on the chemical composition of the paint and all others will be reflected resulting in the observable color of the paint. A paint which appears blue is reflecting the wavelengths of visible light in the blue region and absorbing the wavelengths of the complementary colors which comprise the remainder of the color spectrum. Variables involved with observation by the human eye include the physical state of the observer, lighting, and microscope optics. One of the primary goals of the ASTM and SWGMAT guidelines is to promote consistent analysis. Removing the subjective analysis of color is a step toward achieving this goal. MSP eliminates the majority of these variables and produces a calibrated, objective measurement of the sample's interaction with light. MSP has been proven to be more sensitive than the human eye to differences in color (3). Early MSP was based upon reflectance which measured the amount of white light a sample would reflect. Later developments allowed for transmission spectroscopy which is preferred over reflectance due to the decrease in noise and artifacts (4). The transmitted light is dispersed by wavelength and graphically represented as a spectrum of percent light transmitted versus wavelength. Both black and white are defined as achromatic due to their interactions with visible light as are neutral grays which are hues of black. The color perceived as white is a result of the reflection of all wavelengths of visible light. On the contrary, black objects absorb all wavelengths and the resulting lack of reflected light is perceived as the color black. Achromatic materials reflect or absorb all wavelengths approximately equally and therefore lack what is perceived as color. Because of this, achromatic forensic samples are not typically analyzed via visible MSP. Automotive paint is a non-homogenous suspension of a binder and pigments whose purpose is two-fold: appearance and corrosion prevention. Pigments can be divided into four groups - white, color, inert, and functional. Inert and functional pigments serve as fillers and may impart some beneficial attribute to the coating such as corrosion inhibition or elasticity while white and color pigments account for the physical appearance of the layer. Rutile titanium dioxide is the predominant pigment used in white layers and as a shading agent in conjunction with other pigments. This pigment has a relatively high refractive index of 2.76 while most binders have a refi'active index around 1.5, a difference of 1.26. As light travels from one material to another of a different refractive index, scattering occurs which is important for hiding in paints. Scattering is the internal reflection of light in an object and increases as the difference in refractive indices increases. Hiding prevents the darker undercoat or raw substrate layers from being observable in the finished product. Effective hiding is integral to quality paint appearance and industry demands for superior paint systems have supported the use of titanium dioxide for this beneficial attribute. The pigments used to create black automotive coatings are the products of partial combustion of petroleum products or natural gas and are called carbon-blacks. The exact process and raw materials used to produce these pigments determine their chemical nature: however, they are essentially elemental carbon. Different groups of these carbon- black pigments exist with different particle sizes and jetness, which is a measure of blackness. Channel, furnace, and lamp blacks are examples of carbon-black pigments with increasing particle size and decreasing jetness (5). While titanium dioxide is the preferred white pigment, it absorbs in the violet region which results in a white paint that may display a yellowish tint due to the violet wavelengths that are not reflected. To counter this, manufacturers may add a secondary pigment that will not absorb where titanium dioxide does, such as carbazole violet or even black pigments (5). This type of pigment modification is an example of secondary pigments being used to improve the final achromatic color of the coating. There is also demand on the automotive industry to develop paint systems which are unique and appealing yet still maintain high quality. The use of secondary pigments to impart a chromatic effect in an achromatic color system would be an example of this. The benefit in this instance would be subtle chromatic tinting of the achromatic shade. Automotive paint manufacturers also often add secondary pigments to paint formulations to produce unique vehicle coatings. While the final paint coating appears achromatic, it contains pigments which are chromatic and could yield spectral data. Previous work has been done in analyzing colorless automobile topcoats via ultraviolet or near infrared MSP. No prior work on has been located regarding colorimetric analysis of achromatic color layers. This study examined a set of apparently achromatic automotive paints via MSP. The goals of this project were to determine if it is possible to obtain informative spectral data from apparently achromatic paints in the visible region and if the spectra could be of value in forensic comparisons. Methods One hundred twenty paint samples were obtained from damaged vehicle panels at salvage yards and local body shops. Forty samples each were obtained from vehicles with white, gray/silver, and black topcoats. An additional 40 samples of gray undercoat were obtained from the original vehicular samples resulting in a total sample set of 160. The vehicle data was recorded to track the origin of the samples (Appendix A). Sample set was not intended to be unbiased and was collected with minimal regard to manufacturer and year of production. Table 1 summarizes manufacturer and year of production for the 120 collected samples. Samples for MSP were prepared by manually removing a thin peel of the desired layer and mounting on a microscope slide. This peel was thinned by rolling (Excel razor), immersed in 1.520 Cargille refractive index oil, and a coverslip applied. A second rolling over the coverslip was performed immediately prior to instrumental analysis. This preparation is consistent with techniques reported in published literature (6). Examination via polarizing light microscopy (PLM) was performed with an Olympus BX41 microscope at 400x magnification. This ensured proper preparation and absence of excessive contamination by adjacent layers. Presence of metallic flake or visible pigments was also recorded (Appendix B). Visible microspectrophotometric analysis was performed on a SEE 2100 with 15x objective. Grams 32 software was used for spectral manipulation and instrument control. NIST traceable standards were used to calibrate the instrument. Dark and reference scans were performed prior to analysis of each sample. Samples were analyzed in five locations in absorbance mode. Each location analysis result was an average of ten scans. Manufacturer Number of samples Year of Production Number of samples BMW 1 1986 1 Chrysler 13 1987 1 Chrysler 2 1988 3 Dodge 1989 5 Plymouth 4 Ford Motor Co. 31 1990 8 Ford 19 1991 9 Mazda 5 1992 9 Mercury 7 1993 1 1 General Motors 56 1994 5 Corporation Buick 7 1995 9 Chevrolet 25 1996 14 Geo 2 1997 9 GMC 2 1998 5 Oldsmobile 6 1999 10 Pontiac 10 Saturn 4 2000 3 Honda Motor Co. 3 2001 7 Acura 1 2002 7 Honda 2 2003 2 Hyundai 2 2004 2 Kia 2 Mitsubishi 2 Nissan 4 Subaru 2 Toyota 4 Table 1: Vehicle totals by manufacturer and production date. Results and Discussion The majority of the samples resulted in a featureless curve in the visible range. This is characteristic of the flat absorption expected with achromatic samples. Some samples showed a spectrum with an increase in absorption in the same region. This region was typically between 550nm and 700nm and the absorption varied in intensity. Any absorption that was visually distinguishable fi'om the flat achromatic absorption samples was classified as a positive spectral result. In the black sample set, 11 of 40 yielded spectral information. Seven of the 11 samples demonstrated a slight absorbance at 700nm. Three of the 11 had absorbances from 575nm to 680nm. One sample displayed a very strong absorbance at 620nm with a shoulder at 580nm and a second absorbance at 690nm. Review of microscopy notes revealed that this sample had a blue tinted binder and was taken from a vehicle which appeared black or dark blue-black. Chromatic pigments would then be present and strong absorbances would be expected. The three samples with absorbances at 575nm to 680nm were noted to have chromatic pigment particles visible in PLM analysis. All three were distinguishable from one another. The seven samples with slight absorbances near 700nm did not show any chromatic pigment particles during initial examination via PLM (Figure 1). In the gray/silver sample set, 10 of 40 yielded some spectral variation. Two of the 10 gave weak absorbances at 525nm and 575nm. These samples were not distinguishable based on visible spectra. Eight of 10 resulted in stronger and more distinct absorbances through out the entire visible region (Figure 2). This larger set was found via PLM to have a tinted binder. Similar to the single black sample with strong absorbances, this type 400nm 450 550 530 600 6510 760 750nm Figure l: Absorbances in the visible spectrum may be the result of colored binders or pigments which may or may not be visible in reflected light. A: 1996 Ford Explorer where no pigments were visible via PLM, B: 1999 Mercury Sable with tinted binder, C: 1996 Oldsmobile Cutlass where pigments were visible via PLM. 400nm 450 560 550 660 650 760 750nm Figure 2: Spectra A and B represent gray samples which displayed strong absorbances throughout the visible region due to colored binders. Spectrum C with weaker absorbances at 525 and 575nm is consistent with grey samples with pigments visible via PLM. A: 2002 Honda Odyssey, B: 2004 Saturn Ion, C: 1996 Oldsmobile Cutlass. of response in MSP would be expected with a colored substance. In the initial PLM exam of the set of two samples, chromatic pigment particles were identified Within the white sample set, no informative spectra were obtained. All samples resulted in a very noisy, flat absorption. This is likely due to the prominent white pigment, rutile titanium dioxide. Its high refractive index and effective light scattering attributes prevent light from being transmitted and spectra being obtained. Similarly, the gray undercoat set also gave noisy, uninformative spectra. As undercoat layers are not typically seen in the final automotive finish, there is little need for these layers to be pigmented with a secondary pigment. When the data gained during MSP analysis is compared to the observations made via PLM, three sources of color in the achromatic samples can be identified. In the case of the samples where a colored film or binder was identified, this is clearly the chromatic element. Whether the coloration is a result of a dye element or finely dispersed pigment particles, the effect is visible in reflected light. The MSP spectra were reproducible and were valuable in distinguishing between samples whose binders appeared similarly colored via PLM. Samples in which chromatic pigment particles were visible via PLM typically had a clear binder and while the pigments could be identified the sample did not appear colored. Concentration of the particles varied between samples as did the colors observed. Some samples only displayed one color of pigment while others displayed up to five. The spectra of these samples had greater noise and displayed weaker absorbances than that of the colored film set however; they did not vary based on analysis location within a sample. This indicates that while the heterogeneity of the sample is visible in PLM, the spectral analysis via MSP was fairly consistent within the aperture size utilized 10 (Figure 3). 400nm 450 500 550 600 650 700 750nm Figure 3: Five analyses from sample B34 taken from different locations. B34: 1993 BMW 318i 11 The final group of samples which yielded positive spectral information was not identified as having chromatic pigment particles during the initial microscopic examination. The group had very consistent spectra in MSP with slight absorbances at 700nm. Sample reproducibility within this group was also good. This set was re- examined via PLM and in some cases (3 of 7) faint pigment particles could be detected when the lamp intensity was varied. The presence of these chromatic pigments was not noted upon initial examination due to their faint color and the presence of the dark achromatic pigments. As with any non-homogenous sample, control of preparation, and sampling is extremely important to ensure quality analysis. Sample considerations include obtaining consistent thickness and parallel planes during preparation. Microscopic techniques, including color comparisons must be made under similar conditions, e. g. same instrument and analyst, etc. Sample thinning was performed to obtain the shortest possible path length for improved MSP resolution. The analysis locations were also chosen to improve resolution. The thinnest areas of the mounted sample were scanned regardless of pigment presence or density. The only other consideration made during sampling was to avoid metallic flakes which efficiently refract light to produce their effects and would interfere with obtaining spectra. 12 Conclusions This project analyzed achromatic automotive paints for the purpose of determining whether microspectrophotometric spectra were attainable in the visible region and if those spectra could have forensic value. For white and gray primer coatings, no spectra were obtained and the technique yielded no discrimating value. However, for black and gray paints, some spectra were obtained. This spectral information enabled discrimination of the positive samples from those that did not yield spectra. Additionally, some discrimination was possible within the group of positive samples. When the data obtained via PLM and MSP are used in conjunction, the level of discrimination increases. The work of this thesis also proposes sources of chromaticity in the achromatic materials that could result in spectra. A colored binder is an apparent source and is often observable during preparation and noted via PLM. These samples often originated from vehicles that appeared to have a slightly tinted color such as greenish gray. MSP enabled discrimination between the metarneric pairs. The second source of color identified was agglomerations of pigment particles that were visible via PLM. Spectra were reproducible and displayed absorbances at different wavelengths, allowing discrimination. Samples that showed neither colored binders nor visible pigments comprised the third group. It is proposed that these paints contain some secondary chromatic pigments which are not visible in reflected light but do absorb in the visible region enabling them to produce spectra. As the presence of this chromatic element is not noted in a microscopic examination, MSP analysis becomes significant. Achromatic paints are commonly used vehicle coatings. Recent information shows silver is the most popular vehicle color with 24.1% of 2005 model sales in the 13 fourth quarter of 2004. Black was second on the list with 16.7% of sales. (7) The possibility that achromatic coatings will then be encountered by the forensic analyst is rather high. Paint evidence may be analyzed via polarizing light microscopy and infrared spectroscopy and no discriminating data gained. The application of a microspectrophotometric technique may reveal different absorbance trends in the visible region. This may allow questioned and known samples to be discriminated. Additionally, consistent results in MSP analysis, combined with other analyses, reduces the class size of common sources and strengthens the association between questioned and known material. As a colorimetric technique, MSP analysis can be applied early in the analyst's scheme, preferably after a PLM examination and prior to infrared spectroscopy or elemental analysis. The necessary preparation of samples for MSP analysis is in line with that for there techniques and can be easily incorporated. While this study found no valuable information with the white sample set, the data suggests that while a sample appears achromatic, a MSP spectrum may be attainable. This project advises analysis of all color layer samples which may include very subtly pigmented samples including white. Very pale chromatic samples may appear white especially considering the small sample size typically encountered in forensic settings. In summary, the work of this thesis promotes the use of visible microspectrophotometric analysis techniques in regards to black, and grey or silver automotive paints. Increased discrimination based on the presence or absence of secondary chromatic pigments is the basis for this recommendation. This work has shown these pigments to be present with artifacts both visible and non-visible via microscopy l4 and to yield spectra due to absorbances in the visible region. Substantial forensic information may be gained via this technique. It is therefore recommended that when MSP is regularly included in an automotive paint analysis scheme it should be included in schemes involving black and gray/silver topcoats. 15 Future Work The conclusions of this thesis have raised questions that are in need of future investigation and research. Studies with a larger sample size may be able to significantly determine whether microspectrophotometric techniques offer more resolving power than polarizing light microscopy. Increased sample size with consideration paid to manufacturer during collection would also allow for increased interpretation. Determining what percentage of the automobile paint population yields positive spectral results would be valuable in analyzing the importance of this class. Also, investigatory information may be developed that would be useful when only questioned material is available. Interesting topics to investigate include the effects of weathering and sampling location (roof, door, quarter panel, etc.) Applying the techniques used in this thesis to other apparently achromatic materials may also prove informative. Such materials include achromatic fibers which also utilize pigments and possibly contain secondary chromatic elements. It was noted in the course of this research that certain samples contained very large agglomerations of pigments. These were often gray paints with secondary blue pigments. One sample was analyzed in four locations based on thickness, as was the established method, and the fifth analysis was taken of the secondary pigment. It was possible to place the aperture of the MSP within the border of this agglomeration and obtain a spectrum from the pigment particle alone. The first four locations yielded flat absorptions while the fifth yielded a positive spectrum. Future work into this application of selective scanning could prove beneficial in discrimination between these pigment l6 agglomerations. Effects of size and distribution within samples that contain these pigments would first need to be studied. References were located that recommended the-use of a microtome for sectioning and thinning. While not performed in this research, microtoming could produce thinner samples that could improve spectral analysis. One of the chromatic sources identified in this project included pigment particles identified via PLM. However, there were samples that displayed these pigments but did not yield spectral data. Applying microtoming to these samples prior to MSP analysis would be an interesting project to determine if thinning would truly increase microspectrophotometric analysis. Microtoming may also reduce the sample concentration of chromatic elements by creating such thin samples that the MSP analysis loses resolution. Analysis of microtomed samples that yielded positive spectral results when manually peeled would investigate this possibility and could provide conclusions. l7 APPENDICES Appendix A - Vehicular data collected for all automotive samples Appendix B - Polarizing Light Microscopy Data Appendix C - Visible Microspectrophotometry spectra for all positive samples 18 Appendix A Vehicle Data of all Samples Collected l9 2.85m 88 8 29: ME: 88 osewososmfimmzNos :2 890 888 was 2.85 028 mEEs 58 emEEXFFsEEEN 8o§> so“. Es EsoLo 2.9.5 88 8.8. cu mEIs 82 mmmvsmsnooemhsos «298 s80 83 2.05m 88 8.8. mam His 32 $E2§88m25~ ens. owe 2s 2.8.5 8:: 8.8:“. mEIs 82 5583828815 88m 88% 8s 2.95 88 88 mEEs 82 882288288 885 £855 Es 26:5 88 8 so: 88 mtrs 82 somsomtmvwsmaos 283m 888 82, 2.98 88 88.38 mEIs 82 898588088 22880 5.35 2s 2.9.5 one 859 a mEzs 82 8883828mn_< 883 .980 ms 2995 :2 mExs 82 mimosssmzsaafis :88 so“. is 2995 39 Hrs 82 888059359 :2 890 888 ms 9995 :2 mEEs N8? “8852:8092: $8 852 ms 2925 $2 8 sofa mEEs 32 83.255629 6:98 .56 :s 02.: 9.030230 new—gum N9." 5200 me> Z_> _opos__ axes—.enfiaz 295$ 3880 838m 8 no 38 ”as; ”N 2.3 20 2295 :2 58 ”8 mm>n_m_ 82 2882:8382”: 828.2 so“. so 2225 :2 sea: mm>:m_82 22283858: 88> 82 8.2.5 we 2295 :2 58 89:88 mm>.__m_ 52 8882:2558 2%: 283m 8 8:95 :2 8.8 .8. >55 58 838282822: ex we: we 9295 :2 8588: $35 52 88808838: xo 88s 8:0 no 8:95 :2 8,: 588 > 2.85 82 88 His 82 888384528: :2 890 8:8,“. 8s 21 2.28 82 8 88 8 >56 2o 82 288882202: m... 880 88 80 2.88 82 8. 320 82 828288889 288.. 8.8. 80 2.88 82 8. >3_w_ 82 2228838288 2882 88.2 80 9.5.0 2.88 8:2 0.55 8.3.2 82 8883288ng2 5< 890 8.58 80 2.28 82 88 820—82 888222223202 .88. 380 80 2.88 82 88 mm>...m_ 88 8828820222 2m 32 80 2.88 82 8 8: 88 8.3.2 82 8883082882 8 88m. Eon. 80 2.88 82 8 59. 88 53.282 8282808882 8.8m 88m. 80 2.98 82 8 8.3.2 82 882808802802 88.2. 380 80 2.98 82 88 8.3.2 88 882282888 89¢ 58 80 2.88 82 8586220380882 82828382822 8 8.8m 88.2 86 2.88 82 8 58 8 53.282 888338289222 88 .8832 20 2.88 82 88 mm>3.m_ 82 28228283328 8.53 380 20 2.88 82 .88 8.8.0 8.3.2 82 8880832588 88:5 88.2 20 2.98 82 8 .8. 8 mm>...m_ 82 28832828252 :88. Eon. 20 8:3 2:2 8 89. 88 mm>.__m_ 82 22888880558 88.2 20 .882 2:2 ><20_ 88 8858882822 8.98 882 $0 8:3 22 8.3.2 88 88838288 E. mm 8580 923 20 882 2:2 mm>...w_ 82 883888.80: 992 8.0 2w 88.8 :2 88 >5_ 82 82.5 6.20 m8 6:8 :9 :8: mm>._5_ 58 9:5 28.62 80 6:8 :8 m: 20...: mm>5_ Sow 8329:5559 :82 69.8 66 6288. E: :8: mm>5_ 38. .9625: 3.25 80 6:8 :NF :06: .8. mm>5_ 88 5583855... 95 :55. 58 26:5 8.8 .6 Est: 56$ 82 omomoooaimmgfia :28 296.. v8 23 296.5 :8 8 .8... 8.1.... .8. 8.8.2.5885 .80 :85 80 60. 296.5 :8 8 .8. .: 8.1.... 88 8882288580. .5. ::90 8.8:. :09... 296.5 :8 2055 88 .9560 68:0 95 296.5 :8 205m. 88 :9 935 85 296.5 :8 8 8...: 0.055 88 .9560 60:0 85 296.5 :8 202.5 88 8.93 68:0 55 2:8. :8 8 8.. 88 20:5 88 9x 86> 0.20 85 296.5 :8 99.5 88 885 8m 68:0 8m. 6:8 :8 20<5 88 88888855.... 5.5 62m. 85 6:90.92 8... .8: .8. .: 2055 88 98 :88. :8. 8m. 6:8 :8 8 8...: 905m. 88 38.....38020. .9560 68:0 8m. 6:8 :8 :8: 2035 88 8888.88.85 8932989.... .8. 6:8 :8 8 8...: 9055 88 559995 :8”. 85 6:8 :8 :8: 205m. 88 88888880.... 920 88: 85 6:8 :8 905m. 88 89.30 8.0 85 9.9.5 8.8 .8: .: 905m. 58 3858.18.59”.va m: 86.60 8:8 85 9.9.5 8.8 .8. 905m. 88 8.8888855. :88. :8“. 85 9.9.5 8.8 90:15 88 8:.8.>88~...~8.....0~ 8.93 68:0 8080 9.9.58.8 8 .8. .: ”53.9 :8. 8886588858.. 9855 :8“. 805.0 88.8.8 8 .8.. 58 553.988 .88:.5n.o<850>>.85 88... 8080 99.9:5 :8 8038...: ”53.9 88 58882882668 9.5 8.8.. 68:0 :080 988.:5 :8 :8: ”53.9 88 888082855. 98.8.5 8:5 8050 99.9:5 :8 .8: 8: «53.5. 88 .::8En.Ns.::n.0mxo$mmmr 395 380 momma 2.8.5 8:: ac mm>.__m_ 82 mmmfimoximmozm: seas. 55 188 265 on? 89. mm>.__m No8 mammtmmmmzmufim Ben. Eon awao 2.9.5 on? afcofuzmgimo 82 858255825? 8 gnaw gems. moowo 2.9.5 8:: queer“. amiarmme mmvmovnimzvmgzzx 208$ 52%: momvo 26 Appendix B Table 3: Polarizing Light Microscopy Data ple ier -3 rand Am mina APV van rand Am SE Gsi rand Am Iier Carlo Victoria Am rand Am GT 500 truck 27 Notes flake, properly nted mst flake, properly cont. flake, properly nted amount of primer , properly nted flake, properly nted W30 [Ford IEscort WHITE " W31 Buick Le Sabre limited WHITE " W32 Chevy Lumina WHITE " W33 Clds Cutlass GLS WHITE " . INo flake, properly W34 lPlymouth hcclaim WHITE mounted 35 Chevy S10 Pickup WHITE " 36 Buick Regal WHITE " W37 lFord Contour WHITE little contamination No flake, properly W38 lFord van WHITE Mounted W39 Ford Focus WHITE " A W40 Acura 2.2 CL WHITE " Transparent with flake, G1 lDodge Caravan SE GRAY roperly mounted transparent with flake, G2 Chevy Cavalier GRAY properly mounted G3 Toyota Tercel DX SILVER Heavy flake Transparent blue with G4 Kia Rio CRAY Flake Transparent with flake, pigments visible, some G5 Subaru Loyale SILVER rust and primer cont. heavy flake, G6 Chrysler INew Yorker SILVER little pigment little blue pigment, G7 Ford Mustang SILVER flake, some rust cont. Transparent with flake, G8 Buick kylark SILVER roperly mounted G9 Chevy Lumina Euro 4d SILVER " G10 [Pontiac Grand Prix SE SILVER " G11 Buick Regal Limited GRAY " G12 Clds urora SILVER Faintly blue with flake Transparent with flake, G13 ToLota Camry SE SILVER roperly mounted G14 Mercury Sable GRAY reenish tint (315 Mazda 626 SILVER [game rust present Transparent with flake, G16 lFord Escort Waggn SILVER ome primer cont. ransparent with flake, G17 Mercury Vill_ager SILVER roperly mounted G18 Chevy Lumina SILVER [some primer cont. G19 |Hyundai Accent SILVER lsome pigments visible 28 Ereen with flake G20 Mercury Sable G5 GRAY/GRN nd mica G21 lFord Probe SILVER mica flake l Transparent with flake, G22 Chevy Malibu SILVER roperly mounted 623 Dodge Stratus SILVER ellow with flake Transparent with flake, G24 Ford Escort SE SILVER roperly mounted heavy flake, G25 Kia IRio SILVER little primer cont. Transparent with flake land mica, properly G26 Chevy Beretta GRAY mounted Transparent with flake, G27 Pontiac Grand Am SILVER roperly mounted 628 IMercury Grand Marquis SILVER little primer cont. G30 Chevy Lumina GRAY Heavy flake No flake, properly G31 Dodfi iRam 1500 van GRAY Mounted G32 Buick LeSabre GRAY red with mica 633 Toyota Camry LE DK GRAY inkish with flake dense with red, G34 Toyota Camry GRAY blue pigs Transparent with flake, G35 Saturn Vue SILVER roperly mounted lfragmented, G36 Subaru Forrester SILVER Transparent with flake i L Transparent with flake, G37 DodflcE Neon SILVER roperly mounted G38 Mercury Sable SILVER igments present G39 Clds Cutlass SILVER ome pigments visible blue with flake, G40 Saturn llon GRAY and blue pigments gransparent blue with G45 Honda Odyssey EX van GRAY ome rust B1 Chew Astro BLACK [Properly mounted B2 JMazda lMX-3 BLACK " 33 Mitsubishi Eclipse GS BLACK " B4 IPlymouth Laser LS BLACK " B5 Plymouth Colt BLACK " L IMetallic flake, 86 Dodge Intrepid BLACK large blue pigments Transparent blue, B7 jMercury Grand Marquis LS BLACK ? Flake 29 S ord itsubishi ord MC 6GP GP 8GP 10GP 1ZGP 13G issan 14GP ord Am Avenue aurus CX 4d Prix SE Su 88 10 truck illenia LE XLT cli ier ZX2 18i 10 Blazer ukon XL mina rand Am SE Gsi Carlo 30 mounted nd flake visible mounted mounted more grey n others mounted cont. mounted primer cont. blue mounted contamination cont. mounted mounted flake mounted rust mounted rust cont. mounted nflre rand Am GT 500 truck truck 350 truck ercel DX rk mina Euro 4d W mina GS LE itsubishi cl GS LS 88 31 HITE HITE ITE HITE HITE ITE HITE ITE HITE ITE RAY ILVER RAY ILVER ILVER EVER ILVER EVER kVER &VER kVER lVER RAY/GRN ILVER ILVER ILVER GRAY LACK LACK rust metal cont. rust mounted rust rust/flake cont. mounted color cont. mounted black with ite and mounted Appendix C Visible Microspectrophotometry Spectra for all Positive Samples 32 8a.. 9.8050602 awn Gm 01:98 me 8:50on gofiowosaoboommeomfi 2am; ”v onE ow... 2.5 mm 233 Ill, 1 I! I'll I! {it 1., I .ll; I ' rl.‘ . / . II, / .f .. /r rat-U“, I {I I. .|\! .1 1 pl! / I; a r I a J , [I a I {41, I, I ’4 / ,./. x / I In] / z I} / r z /, .a..ll /l r / to; a . litlilokll/l zlr / . o 1&1”. .1 II. (I ,/ ,./ tun/1., (If, /' i '1! r {I aoueqiosqv 33 8805052 coop com _ mm 295% Co 85.50on abofiouosnobooqmeomg 03%; ”m oSwE a”: 0mm own 7 §\ fifdr/ .lrr. luth‘rurl B 238 \II , ilil‘llrll.rl\} Isltl r\\. l («I t 4 K“! ,\:r x 4 r. x l rlrl\.. ome lmo. Luv. ooueqaosqv / . , x 3 It I I I . a a . 'Inmu .4 4’1 N .1 Vt; / .., / a, . ,. ., cw, . fl . ,1 I I, , ,r/ r, MM, / J. 2.. n I I 34 223.552 coo oocr cow /r\l . (Il\\i/illllr\\. /.\,.\ \x/ . x/ \ . . x . , , I . Ii 14 \\, ,.l.i \\» . \ i A? r'.\\ v.1; t (Hi: \i Tip/.81.,“ . ,\ x I]: \1 A\ ll..\ ,xmr ,c. .., r/ll.\r ,..., I I , ./ fl. 1r , th/K)l\.,\.\ \ (X\ I! I! I . é ‘ .xlii; I: t .. I'll \lr. \ . ~ It .I ll ‘ I. : Ill! I, I. / ollll 4 a ..v...(,. ,1; r 05 363 m 29:8 CO 838on 30893905038me 2:65 6 onE 3 cam com cow cos OOUCQJOSQV 35 68.. 280E052 3m 29:8 .«o 8:50on gofiouofiobooamefig 0365 K onE can 3m oaeow loo. iv. e. m m C U 3 0 la. r8. 36 mmm 2958 .«o 8.50on 30880232038822 2£2> ”w onE 23080an coo w owo 2.5 cm» own 2mm 2.: lull It‘ll}. Tl!" \lr .Ililllr! \) 1’ Ifl \ \ \lrl \r r «\1 44': rl\ i\ U \l.I ‘1 \r,/ rl... I .4\lr 1 535,418 \|' \\ .I‘ \ its ‘ \ \3 l:\ t l! l, "l r.‘ .‘4': llt$ , It. ‘ ' I l,.l/lr. .l/f /. o ‘4 II I I'll. , I .4 41.3% ’1’!!! .rllll. . r'. I ‘1 .. I / / ’1 / ‘/ / eouemosqv (D m. mfiecmw \ 37 «mm 293% .«o 8:50on 90830285893822 2£2> no 2%.. m 88089.32 can act 02. com 02: com can OOUBQJOSQV .. til I] / (III I .I C It :1 N {I I! l/ , I / r .r . x/ ., .1. I I . ..r, r I / I. I! a, 2 f / ~. , , I I z , 1 . , o . v / N c , .( . z / , at... / ,./ I I I. rt; Pun 96.83 I‘ 38 230250.562 one. 0mm 2.3 gm 29:8 .«o 85.588 9080823588822 2£2> A: oSmE own 2.5 own 2*.“ 8 298m Ii": .' 3.....- / all, {lil\\| ii 1‘! . i I it} (k . rlnl, {l [I lr/ II. I If. . it. Ill .7} llcl. Illill‘lil'. Orin-i it 0! I: lil‘ltl‘:\i.||:.l:l.l\..f .‘Ill’ [In/f! .... l {it'll rim»: r '1 ‘,Q I} I .llll.\ll Ill. ll ll 1.5.). all" If! . (Ir-VI. .1 I .11- ll’ l’ a!» '0] .1; «[4! if}. ’1’! l: p l . OI / I I I. / ,4! J2 aoueqiosqv 39 00° F 8808052 owm 0mm own wmm 22:8 mo 83.50on gofioaoamoboamouomz 2£2> n: 93me owe com cow ...l ,, :4! l. ,l I 3. it. tr l I} Q; ,t .. .\..l l - i- , I n L \ I II\\ r I i \I . .e, u, \l WKM .‘x. r1.tt, I \u4ll\\\. . T r.-. all \.,, ,/ 2,1 . tsw. . r . /./fJ., .. z . r.\‘|\l \ [(11 In. . , l I ,i . is. M. [a 8m 2958 I l“... i I\' / ‘ Ir 1 I; ,II fur, i/ I J. r . .. x V]! . I , .sl . ..\. , .1. all I , , . .r/ \l../ I' / list I I I / rill! 4’}; I. r: liliill‘l... r! .o ¢,4 Illil.’ , I (1 Oil tort/rt; .l/ 3. I I ll. 1.! I. I, /, ,le/lillrl 1] / n. l ./l II Irv! III is. .r I. (I r . . l I . /' oouemosqv 4O 0cm cow oar com com k\ rl-til...l..». \\ .\..\l a / \\ CHV ,,. s\ .. .l I tulr . , x i. [\V I la; I.“ .\ x. I) iii A .\ «W, ‘1 {\tf. ,,,,, , .7/7, 4... r. 5|... 1 / I II” . J Xx \‘r‘..:.\\r/r / ‘c. 1 \ It [attir‘rrrk‘lllll’ r1 . ’2 {il\ (’1‘ . / I 1,. 1 7].! ., rllllllhldflllrll xi 1! 4.\‘. I." ,.; ,ll/cla ii. r M’ t .ulv . r (I: .. .l./ I. I (a 95 $363.. 95 29:8 .«o 83508 30830290508822 222 > ”N: 0:9. .2 coc sauwosqv 41 22082.82 ccc _. com own EH— 0388 .«o 58% aboEouonaoboommEoME 03mm; ”2 253m 2.; com r can F Em 295m I r x u p ’ . . , (. I. [If ,. 4 . A I; . I p / ,., :( ,.r t , .. .A, I ’1 1mm. Jr aauchosqv [mt ,,3umm. 42 8202232 near 2.5 wmm 2958 we 85.33% abofioponmoboommohomz 03%; ”E oEwE com 005 com own 08 mam macaw {filiv’qK I- ..\v..,-.}I..-n; \u. Min. l. a - ,i 1. ....,1|‘VD'J \\. v . \IIJ.-\I. .{I ‘01.. .131‘\ I w. K. ”it" .\: le- 11. \I ll «(‘1 {I , I. u I .. fin?) , in. /, .l. b. It I I 1‘ III. I]! .01, 21$ 4 4"?! I UNI, a.” .l ooucqmeqv 43 8808052 or 000 v0 3988 .«o 8.500% FoESonnoboommeog 03mm; “2 oSwE v0 mficam h _ b _ O. .éc. .8. , W ¢ , / R xM/Mfl, / r . ,.../, g .8. x. / .IF . ., In F. 44 IL}- lulu! i: u g 85?. m u moboommobaz 0365 o «958% @0830: SO 29:8 .«o 280E052 com oov com 02. 08 can 02:. 45 OWEQJOSQV ./ 01.. 21V . ,. I / / , .vc 59v a.-. , 1 art // I I , J/ . ,1. J I I 3‘, z: I . ’ I .,..\. fl . r I . s. .r I «(,1 a 1.: at If , w “ m. 3.5mm a\ 8206052 82. com 2.3 30 2988 mo :35on 32:30: 03 Owh 00w own noncommeomz oB§> .2 93me \: I‘\l\‘ ’K'IlI/k‘J‘IU ”l.\\f/I\\\\ulafiu Ia/\/.I’\I l\/ill(\l\l/\|I\. » w w mafimw « /,, /. / .l... f\\.\|.||l|(¢v'.l ¢ 1'...l1.‘t‘\il It)! ,5}: I l [Kl-:11} /I .1 I I. I . (Alli)- I’I ; 5 (II .5 1" I (I! I,” / I} ’1 ’44 / / ’1 I! ,I/ ' ,1. . .‘I/ I v! I oouuqlosqv 46 30 0383 we 8.58% gofioaonqobooameomz 03R; “wfi 2:me 9.32552 82. 8a own 3:. 2.6 can 2.? , .2. 3. 2 .«. 5 4...}, \\ x <1 3.x \ \ ,.\,.-< <:1<,.,3_.,. >\..\ / U. I. \ ”Ca I , x, . <3 2 a? ,\ 5%. ,, ,3 mind mxhrtrw aouaqmsqv 47 ONO 29:8 mo 85.5on 90880235898822 0565 ”a 8:? m as 2.: can can one _ _ jig on. m. wEEmw Inc. oaucqmsqv $N. 48 8308052 con: mmO 2983. we Baboon—m aboESonQobooamEomz Baas ”om oSwE 0mm 006 cm: com com oov 96 29:3 aauuqusqv 49 003 2308082 mmO 29:8 .«o 55.58% abofiouonqoboommeomfi 03%; :N onE OOH 2.5 can _ I Y /. \ \ ”"“' , z/ mmmv 292mm {9' c I. I]; I a]: 3.17.. . I I (.4 (I I (if! .I I a I I / l V (I I. 1 l o I l . l . I . . I r a , '(I . ‘7 :1 {I I . I . . lull/l . I}: o. v} :‘o/ I .. I / n I 1.3. In... aouanosqv 1mm. 50 2808232 669 v 30 2983 .«o 8.58% 30.808290500528822 0365 ”mm own—mi 2.3 of. cow com Gov » o v\ [I p < \C. x I < \ 4N,.\~.{m xxx ‘.. -;.\; \I ~.S) A. Vanni, \.. ,\.»‘./.\H‘ \l. 3“ r I Q 4 R a .\\ \ 30 29:3 \ | ( .\\ {III/SK [\IIKIII: I )..\\ .\ “gin/1.3 X31}... .\ .. IQO / , x. K!) N.-.,,VH.V\...M..H\}1 ‘ \ 11/“) ’V‘ 1‘! V\../.,\,..\/l, fr... [.mo- . .. 4 aauchoeqv 1N... ,,,,.., _ 1?. Iv... 51 $0 2988 .3 85.80% 3083285898832 03%; ”mm oSwE 8808052 owm So an: 08 on...» 001 aauuposqv 2. . . ,. . 4,. _ a ., z z/ / x . ,. I...» w) ,. ,I. V - , .. . , . , w .. ,. ._ h I _ .l@—. J. . ,r 30 29:8 52 oocp 2208232 com con 30 2988 mo 85.58% 3082023589883 0365 #N oSmE of. 2mm own cow $0 295m ,2. \ .3 n/ x... /\ VA...) -. V m .u , \.n.\.u.\\ / .,, v. \\.I/., z m , I u a 0 53 REFERENCES 1. ASTM International. E16lO-02 Standard Guide for Forensic Paint Analysis and Comparison. 2005. 2. Scientific Working Group on Materials Analysis (SWGMAT). Forensic Paint Analysis and Comparison Guidelines. Forensic Science Communications 1999; 2. 3. Martin P. Differentiation of Two Virtually Identical Samples by Microspectroscopy: Green Wool Fibers. CRAIC Technologies 2003. 4. Martin P. Forensic Applications of Ultraviolet-Visible-Near Microspectroscopy. CRAIC Technologies 2004. 5. Wicks ZW Jr, Jones FN, Pappas SP. Organic Coatings: Science and Technology. New York: Wiley, 1992 6. Martin P. Preparation of Paint for UV-Visible Microspectral Analysis. CRAIC Technologies 2002. 7. Dratch D. Top Ten Car Colors for 2005. Available at: http://www.bankrate.com/bnn/news/auto/ZOOSO1 19a] .asp. 2005 54 u«@lillflglllflfllillllwill?"