mm F 42”; (Chairman) / f/{i/M“ - (Membefi 7mm 3 @0054] (Member) ABSTRACT AN EXPERIMENTAL INVESTIGATION OF INFRARED LUMINESCENCE IN BALLPEN AND LIQUID INKS by William H. Storer This study, of interest to questioned document examiners, discusses a non-destructive photographic technique which permits the detection of infrared lumin— escemce in ballpen and liquid inks. It is a technique that can be of assistance in the differentiation of writing inks, and in the restoration of obliterated or erased writings. The phenomenon of infrared luminescence is that fluorescence which occurs in the near infrared spectral region. It is most easily detected by infrared photo- graphy or with an electronic viewing device such as the electronic image converter used in a military "sniper- scope." The equipment used in the study is as follows: a) Light source: A 35mm 500 watt slide pro- jector. While infrared luminescence can be induced by an ultraviolet excitation source, it is most efficiently induced by a high energy incandescent visible light source. Photofloods and similar incandescent bulbs can be used. However, the slide projector permitted better manipulation of the light source, and it generated less heat. b) c) d) 30 seconds. Film: Kodak 35mm High Speed Infrared. This film is approximately eight times faster than standard infrared film; it also exhibits a sensitivity that extends beyond that of stan— dard infrared film. The film was deveIOped for ten minutes at 68 degrees F. in Kodak D-76. Camera: A 35mm Exakta with an f/l.9 lens. Filters: A 10% aqueous solution of copper sulfate in a flat sided one pint wine bottle having a light path of 35mm was placed in front of the slide projector lens. The c0pper sulfate filter served to absorb the infrared that was generated by the slide projector bulb. A Wratten 87C infrared transmitting filter was used over the camera lens. Its function was to absorb any visible light that was reflected from the ink samples and from the various papers upon which the ink lines had been drawn. The use of the copper sulfate filter and the 87C filter ensured that only infrared lumin- escence and not reflected infrared or visible light was recorded on the film. A Kodak +2 close-up attachment was used on the camera lens in order to provide an image that was larger than that provided by the standard camera lens. The technique provides a superior sensitivity to weak infrared luminescence in comparison to the results achieved with the electronic image converter, or with standard speed infrared film. In addition, previously reported film exposure times of from 15 to 30 minutes can by this technique be reduced to approximately 15 to The use of the Kodak High Speed Infrared film in a 35mm camera at a lens opening of f/l.9 permitted ii the reduced exposure time. One of the salient features of the technique is its capability of supplementing or even surpassing the results provided with ultraviolet examinations or with standard infrared photography. The study Specifically demonstrated (1) that all inks do not exhibit infrared luminescence, (2) that inks of colors other than blue may exhibit infrared luminescence, (3) that inks which exhibit similar visual colors may exhibit distinctly different infrared luminescent properties, (u) that the color of the paper upon which an ink writing appears can significantly influence the infrared luminescent properties of the ink, (S) that the ultraviolet characteristics of a white paper stock apparently do not affect the infra- red luminescent properties of an ink, (6) that caution is required when evaluating the infrared luminescent properties of a liquid ink, because a liquid ink from an unshaken bottle can exhibit inconsistent luminescent characteristics. iii AN EXPERIMENTAL INVESTIGATION OF INFRARED LUMINESCENCE IN BALLPEN AND LIQUID INKS BY William H. Storer A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE School of Police Administration and Public Safety 196% A ’7 f/‘(./ JCK A" Q 5 MM ACKNOWLEDGMENTS The author wishes to express his appreciation for the constructive criticism and invaluable guidance provided by Mr. George G. Swett in bringing the experi- mental phase of this study to completion. The author wishes to acknowledge also the guidance and criticism provided by Mr. P. Rajeswaran and Mr. Ralph F. Turner both of whom contributed to the drafting of this study. The study was conducted in the Laboratory Division of the St. Louis Metropolitan Police Department, Lieutenant Dell R. Watts, Laboratory Commander. CHAPTER I. II. III. IV. TABLE OF CONTENTS PAGE THE PROBLEM AND DEFINITIONS OF TERMS USED . . The Problem . . . . . . . . . . . Statement of the problem . . . . . . Importance of the study . . . . . . Hypothesis . . . . . . . . . . . Definitions of Terms Used . . . . . . Luminescence . . . . . . . . . . Infrared luminescence . . . . . . . Infrared spectrum . . . . . . . . METHODS OF DETECTING INFRARED LUMINESCENCE . Infrared Image Converter Tube . . . . . Photographic Method . . . . . . . . Advantages and Disadvantages of the Methods. Infrared-Sensitive Films . . . . . . . REVIEW OF THE LITERATURE . . . . . . . Literature on Detection of Infrared Luminescence . . . . . . . . . . Literature on Electronic Image Converters . EQUIPMENT AND MATERIALS USED IN THE STUDY . . Photographic . . . . . . . . . . . Camera . . . . . . . . . . . . Film 0 O O O O O O O O O O O 0 vi 12 13 15 20 21 27 30 30 30 32 CHAPTER PAGE Exposure time . . . . . . . . . 32 Film developer and development . . . 32 Stop bath and fix . . . . . . . 33 Light Source and Copper Sulfate Filter. . 33 Light source . . . . . . . . . 33 Copper sulfate filter . . . . . . 3% Writing Materials . . . . . . . . 38 Ballpen inks . . . . . . . . . 38 Liquid inks . . . . . . . . . 38 Paper stock . . . . . . . . . 38 V. EXPERIMENTAL PROCEDURE . . . . . . . . H0 Experimental Controls . . . . . . . “0 Unaltered Ink Lines . . . . . . . . Ml Eradicated Ink Lines . . . . . . . H2 Erased Ink Lines . . . . . . . . . H2 Obliterated Ink Lines . . . . . . . H2 Chemical Tests for Constituents . . . . #3 VI. FINDINGS AND CONCLUSIONS . . . . . . . H5 Unaltered Ink Lines . . . . . . . . US General . . . . . . . . . . . H5 Experimental photographic technique vs. Converter tube technique . . . . us 'White paper stocks . . . . . . . H6 Colored paper stocks . . . . . . H6 vii CHAPTER PAGE Visual ink colors . . . . . . . 47 Directional changes in pen movement . . H7 Old or poorly mixed liquid inks . . . H8 Eradicated Ink Lines . . . . . . . . ”9 Erased Ink Lines . . . . . . . . . 50 Obliterated Ink Lines . . . . . . . . 50 Chemical Tests for Constituents . . . . 51 VII. SUMMARY . . . . . . . . . . . . . 53 IBIBLIOGRAPHY . . . . . . . . . . . . . . 56 CITED REFERENCES . . . . . . . . . . . . 59 TABLE I LUMINESCENCE CHARACTERISTICS OF BALLPEN INKS . . . . . . . . . . . . 61 TABLE II LUMINESCENCE CHARACTERISTICS OF LIQUID INKS . . . . . . . . . . . . 65 TABLE III CLASSIFICATION OF BALLPEN INK INTO DYE CONSTITUENT GROUPS . . . . . . . 66 SCHEME FOR THE PRESEMPTIVE IDENTIFICATION OF BALLPEN INK FORMULATIONS. . . . . 68 APPENDIX A. LIST OF BALLPENS EXAMINED . . . . 71 APPENDIX B. LIST OF LIQUID INKS EXAMINED . . . 73 APPENDIX C. LIST OF PAPER STOCKS . . . . . . 7H APPENDIX D. PHOTOGRAPHS . . . . . . . . . 75 viii LIST OF TABLES TABLE PAGE I. Luminescence Characteristics of Ballpen Inks . 61 II. Luminescence Characteristics of Liquid Inks . 65 III. Classification of Ballpen Inks Into Dye Con- stituent Groups . . and . . "Scheme for the Presumptive Identification of Ballpen Ink Formulations" . . . . . . . . . 66 ix LIST OF FIGURES FIGURE PAGE I. A Schematic of the Excitation and Detection of Infrared Luminescence . . . . . . . 18 2. A Schematic of the Electronic Image Converter. 19 3. Diagram of Photographic Set-Up . . . . . . 35 H. % Transmission vs. Wavelength for the 87, 87C, 88A, and 898 Filters . . . . . . . . 36 5. % Transmission vs. Wavelength for 10% Aqueous Copper Sulfate, for Water, and for 50% Aqueous Nickel Sulfate . . . . . . . 37 6. through 18. Photographic series . . . . . 75 LIST OF APPENDICES APPENDIX PAGE A. LIST OF BALLPENS EXAMINED . . . . . . . 71 B. LIST OF LIQUID INKS EXAMINED . . . . . . 73 C. LIST OF PAPER STOCKS . . . . . . . . . 7” D. PHOTOGRAPHS O O O O O O O O O O O O 75 xi CHAPTER I THE PROBLEM AND DEFINITIONS OF TERMS USED Several research workers in the field of questioned document examination have called attention recently to a relatively unexplored investigative technique. It is one whereby the phenomenon of infrared luminescence may be detected or shown to be absent in inks and other writing materials. The potential value of this technique as a means of detecting alterations and additions, as a means of restoring obliterations, or as a means of demon- strating differences between writing materials has been discussed in the literature (l,2,H,5,6,7,1u). However, no formal detailed reports have as yet been presented. I. THE PROBLEM Statement 2: the problem. It was the purpose of this study (1) to present a simple technique which would produce effective infrared luminescence detection; (2) to determine the conditions and circumstances under which effective detection may be expected; (3) to determine the practical limits of the technique. Importance g: the study. The examination of questioned documents is usually limited to non-destructive techniques. Regardless of its form, the value of a questioned record or document may and usually does trans- cend its temporary role as evidence when it is under suSpicion. The evidential value of a bullet, a blood stain, a hair, or a paint fragment is created with the inception of its related offense. Their values normally cease when the judicial processes have been fulfilled. Not so with the questioned document; particularly a questioned doc- ument which eventually discloses its genuineness. The destruction, obliteration, or alteration of a document during the examination may be an act exceedingly more offensive than the suspected act under immediate consider— ation. Accordingly, chemical and similar destructive test methods are rarely permissible. The competent examiner of questioned documents strives to establish facts by thorough examinations. However, thoroughness does not preclude his responsibility for maintaining the eviden- tial integrity of the document in question. The elimination of chemical and other altering or destructive test measures from the category of investi- gative techniques intensifies the importance of inter- related optical and spectrum analyses--or more simply, the importance of the visual examination. Accordingly, the examiner finds himself concerned with the investiga- tive powers of radiant energy in the form of light. He constantly seeks non-destructive techniques which will supplement or improve the current non-destructive methods, several of which are: high and low power magnification which has the capability of revealing information not discernible to the unaided eye, and which often indicates the results that may be obtained from subsequent methods of examination (8); oblique and transmitted illumination which have the capability of disclosing indented writings, erased areas, and watermarks (9); filter photography which has the capability of restoring obliterated writings and over-lapping multi-colored writings (10); masking techniques which have the capability of separating over- lapping multi-colored writings or stamping inks (6,11); infrared photography which has the capability of restoring obliterated, charred, erased, or otherwise invisible writing (12); fluorescence induced by ultraviolet illum- ination which has the capability of detecting and deciph- ering chemical alterations or eradications, of differ- entiating certain writing materials through observable differences in color of fluorescence, and the detection of invisible writings by the photography of ultraviolet images (13); selective wavelength examinations through dichroic filters (1H); the use of electronic image converter tubes as substitutes for straight infrared photography (15); and the adaptation of automatic re- cording microdensitometers in the recognition and evaluation of specular and physical characteristics of writing materials (16). There are, unfortunately, instances when the investigative capabilities of the current methods fail to reveal any latent significant information that a questioned document may bear. ACcordingly, there exists the necessity for the deveIOpment of additional non- destructive investigative techniques. The phenomenon of infrared luminescence (that fluorescence which occurs in the near infrared region of the spectrum) provides an additional non-destructive method of examination. In the present study a technique was devised and employed to photographically detect and record the infrared luminescent capabilities of writing inks. Hypothesis. The detection of infrared luminescence in writing materials offers the examiner of questioned documents a technique that can supplement or extend his current investigative potential. II. DEFINITIONS OF TERMS USED Luminescence. The general term "luminescence" includes the emission of light that results from all processes except incandescence. It is a phenomenon of radiation which occurs during and/or after which a material capable of luminescence has been exposed to some form of external photon radiation. Since the generic term (Latin, Lumen, "light" + -escence) denotes a process of generating radiation during and after ex- citation, luminescence includes fluorescence and phos- phorescence. Fluorescence describes the emission of light at the same time as excitation; phosphorescence describes the emission of light that follows excitation.l According to Leverenz, luminescence should be limited to the emission of visible radiation (1.7 e.v. to 3.1 e.v. photons); but this traditional limitation is generally ignored because the human eye is but one of many photosensitive devices now being used to detect luminescence.2 e.g., image tubes and photographic emulsions. 1 Humboldt W. Leverenz, An Introduction to Lumin- escence pf Solids (New York: JoHH Wiley 6 Sons,_IQSU), pp. Vii‘Viiio 2 Ibid., p. 136. 31bid., p. use—usu. Luminescence, as characterized by Leverenz, is the emission of radiation that is in excess of the thermal radiation produced by heat in a given material. Thermal radiation is radiation that is emitted after absorbed energy is converted into low-quantum-energy heat that diffuses through the material. Luminescence radiation is radiation that is emitted after an appreciable part of the absorbed energy is temporarily localized as relatively high-quantum-energy excitation of atoms or small groups of atoms.u Luminescence results when an excited atom or group of atoms is raised to a higher energy level and then returns to a state of lower energy.5 The Optical energy difference between the two levels is emitted in the form of photons. In the case of Optical excitation, the emitted radiation almost always has a lower frequency than the exciting radiation. Further, it is essential for the exciting radiation to be absorbed if it is to be re-emitted as some form of luminescence. According to the law of conservation of energy, the emitted light must have the Leverenz, 92. cit., pp. 1-2. Jack De Ment, Fluorescent Chemicals, (Brooklyn: Chemical Publishing Co., 19H2), pp. H-S; Humboldt W. Leverenz, An IntroductiOn to Luminescence (New York:John Wiley 8 Sofi§,I950), CHapST-I and V: Peter Pringsheim, Luminescence of Liquids and Solids (New York: Interscience Publishers, 1833), pp. 8—13. same energy as or smaller than the incident radiation, i.e., it must have a longer wavelength. Familiar examples of luminescence which is visible to the unaided eye are the narrow spectral lines and bands of radiation emitted by (l) electronically excited gases, such as in lightning and neon lamps, (2) certain oxidizable organic matter in liquids exposed to air, for example in glowworms and fireflies, and (3) coatings of tiny phosphor cyrstals excited by invisible alpha particles, electrons, and ultraviolent, as in luminescent watch dials, television picture tubes and "fluorescent" lamps. In all these cases of luminescence, the temper- ature of the luminescing material is best maintained near or below room temperature. Also, the quality and quantity of luminescence radiation are strongly dependent on the nature of the emitting material; the quality and quantity of thermal radiation depend chiefly on the temperature 7 rather than on the nature of the emitting solid material. Infrared luminescence. A phenomenon similar to visible fluorescence under ultraviolet light except that the emission occurs in the infrared region and hence is invisible to the human eye. Chapter II discusses two 6 . De Ment, 220 Clto,"po lo Leverenz, op. cit., p. 2. relevent methods of detecting infrared luminescence. While infrared luminescence can be induced by violet and ultraviolet excitation, Barnes (H) and Godown (1) found that it is most efficiently excited by visible light from high-energy incandescent lamps. According to Leverenz this luminescence phenomenon, which has as its excitation source low-energy photons (visible light or UV), would be a luminescence desig- 8 nated as photoluminescence. Infrared Spectrum. That region of the spectrum that extends out indefinitely from the red end of the visible spectrum. As the wavelengths increase, the radiation emerges into heat waves and finally into radio waves. For the purpose of this report, the infrared spectrum will encompass that region from approximately 7000 A to 9000 A. This infrared region is that to which the infrared film used in this study was sensitive. Max- imum sensitivity of the film was within the range 7700 A to 8H00 A.g Leverenz, pp. cit., Table 10, p. 1&8. 9 . . "Cine-Kodak and Kodak ngh Speed Infrared Film," Kodak Pamphlet No. M-9, Rochester: Eastman Kodak Company. CHAPTER II METHODS OF DETECTING INFRARED LUMINESCENCE Infrared luminescence can be detected most con- veniently by either of two methods. One method utilizes an infrared image converter tube of the type present in the military sniperscope. The second method utilizes any suitable camera loaded with infrared film. (Figure I). I. INFRARED IMAGE CONVERTER TUBE This device has an objective lens that focuses the primary image on a cathode which is so sensitized that it will give off electrons when illuminated by ultra- violet, visible, or infrared radiation. A typical cathode for this purpose is a silver-cesium oxide-cesium film. When an image is projected on the cathode, electrons will be emitted from its surface in proportion to the illum- ination at any point. The emitted electrons form an elec- tronic image which is a reproduction of the light image. The electronic image is focused on a zinc silicate phosphor screen after the image has been accelerated to a high velocity by a series of high-voltage electric fields. The electrons (Electronic image) falling on the screen excite it to fluorescence, and a visible green image is seen on the screen. The image is viewed through an eyepiece. If 10 a permanent record is desired, the image can be photo- 1 2 graphed with any green sensitive film. ’ Figure 2 illustrates the infrared image converter tube. Since the military device is designed to focus on objects at a distance greater than four feet, it is nec- essary that a close-up attachment be fitted over the objective lens. A close-up attachment of approximately three diopters will permit a viewing distance of about nine inches. Supplementary lenses of other than three diopters may be used if different viewing distances are required. The use of an image converter tube device for the detection of infrared luminescence requires a totally darkened room and a prOperly filtered light source to ensure that no stray light will fall on the object and interfere with the luminescence phenomenon. A source of high incandescent energy is used to illuminate the object and to excite the infrared luminescence which the object may be capable of producing. However, all incandescent lamps emit more energy in the infrared than in the visible 1 Walter Clark, Photography by Infrared (New York: John Wiley 3 Sons, 19%): pp. 123-1713.” David Barnes, "Infrared Luminescence of Minerals," Geological Survey Bulletin 1052-C (Washington: Government Printing Office, 1958 3 Leverenz, pp. cit., p. ”60. 11 range of the spectrum. If infrared radiation is per- mitted to strike the object under observation, some of the infrared radiation will be reflected and will be observed on the screen. Such reflected radiation can either mask completely or at least weaken the sought for infrared luminescence. In addition, reflected infrared may be erronously identified as infrared luminescence. It is therefore necessary that the infrared radiation which is emitted by the light source be eliminated. Effective filtering may be accomplished by placing a solution of copper sulfate of suitable concentration in front of the incandescent light source. Proper pre- cautions must be instituted to ensure that no stray un- filtered light strikes the object. If the copper sulfate solution is effective in filtering infrared from the light source, then only visible light will strike the object and will accordingly excite any latent infrared luminescence. The infrared image converter is sensitive to vis- ible light as well as to infrared. Therefore, any object which reflects visible light can be observed on the screen. If we desire to observe only infrared luminescence, the reflected visible light must be filtered before it strikes the image tube. Effective filtering is accomplished by attaching an appropriate infrared transmitting filter over the objective lens of the image converter tube. 12 II. PHOTOGRAPHIC METHOD The photographic method is essentially the same as the image converter tube method. The major difference is that a camera loaded with infrared film is substituted for the image converter tube. The filtering procedure is identical to the already described. That is, the incandescent source is filtered through a copper sulfate solution, and the reflected visible light from the object is filtered by placing a suitable infrared transmitting filter over the camera lens. The photography is per- formed in a totally darkened room except, of course, for the filtered light source. (See Fig. 3). One factor which must be considered with infra- red photography is that of focusing compensation. Infra- red rays, because of their longer wavelength, do not focus in the same plane as visible rays. It is usually necessary to make an increase in the lens-to-film distance in order to correct for the focusing difference between u infrared and visible rays. For best definition, infrared LiWalter Clark, Photographypy Infrared (New York: John Wiley 8 Sons, 19H67, pp. lQ-IB. 13 photographs should be exposed with the smallest lens Opening that conditions will permit. This is partic- ularly important since adjusting the lens-to-film distance corrects only for longitudinal color aberration; ordinary photographic lenses are not corrected in other aberrations for the infrared part of the spectrum. III. ADVANTAGES AND DISADVANTAGES OF THE TWO METHODS The image converter tube method and the photo- graphic method each offer distinct advantages and dis- advantages. The prime merit of the image converter is its capability of rendering rapid infrared luminescence detection. The image converter tube and its necessary accessories require little more bench space than a stan- dard laboratory microscope. It can thus always remain set up for immediate use; an examination with the image converter could probably be completed in the time it would take just to prepare a camera in the photographic method. The undesirable features of the image converter method are more numerous. The physical hazards of working with an electrical device which generates high voltage is a most important consideration. Since most of the available image converters are secured through the surplus market, the purchaser must thoroughly check 1% the entire unit to ensure that the wiring and other electrical connections are securely insulated and safe. At the time of this report surplus image converters are not readily available on the market. Those image con- verters which are available will often be of poor quality or in poor mechanical condition; the purchaser of a sur- plus "sniperscope" or "snOOperscope" assumes the risk of an early mechanical breakdown. To add to the difficulties, re- placement parts are practically non-existant. The Operator of an image converter will usually find that the sensitivity of the device to infrared luminescence is less than that of infrared film. The sensitivity of the Operator's eyes are also a factor that can contribute to the problem. It is certainly conceivable that faint luminescence may go undetected when both of these sensitivity factors come into play. The resolution of the image converter is also less than that of the camera lens-infrared film combination. Since the phosphor screen of the image converter was not designed to produce needle-sharp images, the oper- ator can expect to experience difficulty in deciphering restorations. The photographic method offers few, if any, real disadvantages. Its capabilities of providing superior sensitivity and resolution outweigh its equipment require- ments and lengthier manipulations. 15 Because of the anticipated advantages of superior sensitivity and resolution, the photographic method was used in the preparation of this study. An image con- verter was used to compare its own sensitivity with that of the photographic experimental method. IV. INFRARED-SENSITIVE FILMS Kodak High Speed Infrared Film (HIRAOZ) was used in the preparation of this study. Since Kodak infrared materials are ordinarily used in the United States, this discussion will be limited to Kodak products. Most photographic films, whether they are ortho- chromatic or panchromatic, are not sensitive to infrared. Only when the emulsion is treated with Special dyes can infrared sensitivity be attained.5 While some of these dyes have been known for a long time, it was not until 1931 that dyes were discovered which made infrared photo— 6 graphy as Simple as photography with normal materials. In 1925, when H. T. Clarke at the Kodak Research Laboratories was preparing the dye Kryptocyanine, it was noted by him that a second dye was formed during the reaction. This second dye was found to sensitize film from 6,500 A to 9,000 A; it was termed Neocyanine. The max- imum sensitivity of Kryptocyanine extended only to 8,000 A. 6 "Infrared and Ultraviolet Photography, " Kodak 16 By treating the Neocyanine sensitized plates with ammonia, it was possible to photograph the spectrum to beyond 10,000 A. In 1930 using Neocyanine plates, Babcock, of Mount Wilson Observatory, photographed the solar Spectrum as far as 11,63” A, the farthest limit that had ever been photographed. Babcock also made the first photograph in total darkness using heat rays, the plate being sen- sitized with Neocyanine.7 During the years 1931-1935 a new group of sen- sitizers were develOped. This group, called the tri- carbocyanines, made it possible to photograph the Spectrum to beyond 11,000 A. Meggers and Kiess, at the Bureau of Standards in Washington, succeeded in photographing hundreds of new Spectral lines out to about 12,000 A. Since 193u—1935, develOpment of the tetra- and pentacarbocyanines have permitted the sensitizing of photographic plates that will record infrared out to about 13,600 A.9 Kodak infrared materials such aS Kodak Infrared Sheet, Kodak Infrared 35mm IR135, Kodak High Speed 35mm IRM02, Cine-Kodak High Speed, Kodak Infrared 7 Clark, pp. cit., pp. 77-90. Clark, loc. cit. 17 Sensitive Plates are sensitive not only in the extreme red and infrared regions (6,300 A to 9,000 A) but are also sensitive in the blue region (3,500 A to 5,300 A). These ranges are approximate.10 With infrared sensitive materials it is necessary to use over the lens a deep orange or red filter to absorb blue and sometimes visible red light if the photo- graph is to be made only by infrared radiation. Several of these filters are discussed in Fig. A. "Photographs can be made with infrared films without a filter, but the rendering will be similar to that of a blue-sensitive film. The quality will be less satisfactory than that produced by either orthochromatic or panchromatic film. Reds, greens, and yellows will be reproduced darker than normal; blues, lighter."ll The latitude of infrared materials is less than that of most panchromatic films. - 12 Therefore, correct exposure is more critical. 0 "Infrared and Ultraviolet Photography," op. cit., 11Ibid., p. H. 12 , Ibid., p. U. 18 msRARgD FILM SNOOP ERSCOPE |NFRARED * LUN\\N ESCENCE V|S\BLE LIGHT ABSORBED /\ A I l I c ‘ ' ’. INFRARED \ TRANSNHTTING / FlLTER Iogcoppm SULFAT \ Cu. sol-5&0 ., D OCUMENT FIGURE 1 A SCHEMATIC OF THE EXCITATION AND DETECTION OF INFRARED LUMINESCENCE (Similar to Wilson, (5) 19 FIGURE 2 13 SCHEMATIC OF ELECTRONIC IMAGE CONVERTER Infrared radiation passes through an infrared transmitting filter (F). The radiation is focused by the optical lenses (L) upon the photocathode (P) of the image tube (IT). The electrons released by the photocathode (P) fall upon a fluorescent screen (W) covered with a phosphor of a composition Similar to that of cathode-ray tubes. Electrons activate the phosphor (S) to a greenish Fluorescence and the electron image formed on the screen (8), is observed through a magnifying eyepiece (EP). Zaboj V. Harvalik, "An Electronic Image Con- verter and Its Use in Chromatography," Anal. Chem., 22:11u9, September, 1950. CHAPTER III REVIEW OF THE LITERATURE The literature abounds with information and techniques which deal with the infrared spectrum and with standard techniques of infrared photography. The infrared Spectrum and its photography are, of course, related to the present study. The literature review that follows will deal primarily with works which discuss infrared luminescence and its detection. There have been included several summaries of papers which discuss the electronic image converter. These papers do not discuss the use of the image con- verter for the detection of infrared luminescence. How- ever, these references have been included as information sources for those interested in the construction and in the criminalistics applications of the electronic image converter. 20 21 I. LITERATURE ON DETECTION OF INFRARED LUMINESCENCE Godown was one of the first to report the potential value of detecting infrared luminescence in writing materials.l His preliminary experiments dealt with the electronic image converter (military surplus sniperscope) and with infrared photography. He achieved satisfactory results with a 5 percent aqueous copper sulfate solution in plastic cells to filter the light source, and Wratten 87, 87C, 88A, and 898 filters on the camera lens. Results were unsuccessful when a solution of nickel sulfate was used at the light source. No exposure or film type data was presented. Godown suggested various areas in which experimental endeavors might be directed. These first efforts by Godown were directly responsible for the inception of continued research in the "questioned document" area by this writer and others. Somerford described the early work performed by Godown and credits Godown with making the first photograph Showing infrared luminescence of writing Linton Godown, "Infrared Luminescence," unpublished paper read at the American Academy of Forensic Sciences, Chicago, February, 1960. 22 materials.2 Somerford also discussed John Gosling's (Kodak Research Laboratory) unpublished research which yielded satisfactory results with a 5 or 10 percent copper sulfate solution in a one centimeter glass or lucite chamber at the light source, and Wratten 87, 87C, 88A, and 988 filters on the camera lens. Gosling used Kodak Infrared Sheet Film, Kodak Infrared Aero- graphic Film, Kodak High Speed Infrared Film, and Kodak Photographic Plates. Gosling suggested a 500 watt projector lamp as the light source and an exposure approximately twelve times that required for a normal reflected infrared photograph. Somerford also reported that unpublished research by David Crown (San Francisco Postal Laboratory) "revealed that of 1&8 ballpen inks examined 66 exhibited luminescence. The latter group generally contained dyestuffs consisting of methyl violet and Victoria blue. However, when these two dyes were blended with phthalocyanine dye, luminescence was not achieved. It follows that success in the application of IR-luminescence is dependent upon the presence of certain ink dye components and the absence of induline, and phthalocyanine blue dyes." Somerford included in his report several schematic drawings by Simeon Wilson 2 g 0 Albert W. Somerford, "Technique Of Infrared Lumin- escence," Identification News, pp. u-6, 10, July, 1961. 23 (Chicago Postal Laboratory) which depict the excitation and recording techniques of infrared luminescence. Gosling presented a technique whereby various combinations of light filters, radiation wavelengths, and photographic films permit the selective discernment of overlapping multi-colored stampings on bank checks which are otherwise unreadable.3 Gosling mentions that the use of infrared luminescence is one technique which may assist in the differentiation and separation of the unreadable stampings (imprints). For the photography of infrared luminescence he used an 8x10 view camera at 1:1 magnification, an 8-inch f/7.7 Kodak Ektar lens covered with a Wratten 87 filter, and two 500 watt projector lamps covered with glass cells (2 cm. thick) containing 10 percent copper sulfate in water placed at a distance of 2H inches and at an angle of #5 degrees from the copy board. Exposures were made on Kodak Infrared Aerographic Film for two minutes at f/7.7. Negatives were developed for five minutes in Kodak D-l9 at 68 degrees F. J. W. Gosling, "Photographic Separation of Colored Imprints by Masking Techniques," Identification News, 12:H-10, May, 1962. 2H Stoll discussed Six components and character— istics of papers that provide means of paper identif- ication: fibers, Sizing chemicals, pigment fillers and coatings, physical characteristics, watermarks, and reflection properties,” In his discussion Of reflection prOperties, Stoll mentioned that comparing the infrared luminescence of paper samples by photography can reveal differences. A photograph is presented which Shows the infrared luminescence comparison of sixteen papers. Barnes, in studying nearly 200,000 mineral specimens at the U.S. National Museum, found that 1,500 Specimens would exhibit infrared luminescence. He used a 500 watt photospot as an excitation source, and a surplus military sniperscope as a detecting device. A 5 percent aqueous solution of COpper sulfate in a plastic chamber was used to filter the light source; four filters of varying infrared transmission were used in front of the image converter lens. The apparatus was supplemented with an ultraviolet light source and a weak infrared light source. u Robert P. Stoll, "Analysis and Identification of Paper," Identification News, 13:4-10, 12, September, 1963. 5 David Barnes, "Infrared Luminescence of Minerals," Geological Survey Bulletin 1052-C (Washington: Government Printing Office, 1958. 25 The source of weak infrared radiation (25 watt bulb) was covered by an infrared transmitting filter. It was used primarily to distinguish infrared luminescence from reflected light that was leaked by the filters on the sniperSCOpe. Harvalik used an image converter tube to detect infrared luminescence, infrared reflection, and ultra- violet reflection on chromatOgraphic columns.6 Detection of infrared luminescence was achieved by a mercury arc source that was filtered by a combination of a Corning 3389 and a “#07 filter; a 5860 Corning filter was used when a higher excitation source was required. A Corning 2590 was used to cover the converter tube. Reflected infrared was observed by placing a Corning 25u0 filter in front of the light source. Reflected ultraviolet was detected by using a mercury arc as a light source in connection with a Corning 5860 ultraviolet filter; a Corning 5860 filter was also attached to the converter tube in order to prevent any visible ultraviolet fluor— escence from being observed. Harvalik also presented Schematic diagrams of the converter tube and its power source 0 Zaboj V. Harvalik, "An Electronic Image Converter and Its Use in Chromatography, "Anal. Chem., 22:11H9- 1151 (1950). 26 Zyuskin discussed the photography of ultraviolet fluorescence and infrared luminescence. In his discussion of infrared luminescence he suggested that effective dif- ferentiation of some inks was possible by varying the copper sulfate concentration (9 to 120 grams/liter) in combination with radiation sources of various wave- lengths and camera filters of varying wavelength char- acteristics. By use of the various filter and source combinations he found that it was possible to decipher and make readable overlapping and multi-colored ink stampings. The technique of Zyuskin is Similar in concept to that set forth by Gosling's masking tech- niques. Much of the technical clarity has been lost in the translation from the original Russian; the Russian filter designations could not be related to American filters. Hoover and MacDonell discussed glass filters that they found to be useful in infrared luminescence detection. N.M. Zyuskin, "The Luminescence Photography by Ultraviolet and Infrared Radiation," Translated from: Zhurnal Nauchoi i Prikladnoi Fotografii i Kinematografii 5 (u), 27u-279, 1960. Through courtesy of Eastman Kodak, Rochester, New York; Translated by Carlo A. Bauman. 8H.L. Hoover and H.L. MacDonell, "Infrared Lumin- escence Using Glass Filters," Journal p: Forensic Sciences, 9:98-99, January, 1965. 27 They described: filters that can be used in place of the liquid cOpper sulfate filter; Sharp cut—off filters that are available for differentiating luminescence bands of intermingled substances; filters that are useful with long wavelength sensitive infrared films; and the use of photoflash and electronic flash as radiation sources. Wavelength vs. %Transmission curves for infrared films and filters are also presented. 28 II. LITERATURE ON ELECTRONIC IMAGE CONVERTERS Kuhn in 195H described his adaptation of a British type CVlH7 image tube for use in the infrared examination of questioned documents (as a substitute for standard 9 infrared photography). Two schematic diagrams, a parts list for construction of the image tube housing, and a parts list for the construction of a power supply are provided. Kuhn suggested that other applications of the image converter tube include its use in analytic chem- istry, chromatography, the examination of inks, paper, hairs, fibers, and other objects by a comparison of their properties of reflection, absorption, and fluor- escence in infrared and ultraviolet light as seen through the image tube. Kuhn in 1959 discussed the modification and adaptation of a World War II army surplus sniperSCOpe, RCA type 1P25 for use as a substitute for standard infra- 10 red photography in the examination of questioned documents. A schematic Show the electrical circuit of the sniper- scope power supply. Kuhn compares the British CV1H7 tube with the RCA 1P25. 9 . . . Richard Kuhn, "Infrared Examinations With an Electronic Image Converter," The Journal of Criminology, Criminal Law and Police Science, H5:h86—989,—No. u, 195%. 0 Richard Kuhn, "Recent Developments in the Use of Infrared Image Converters," Journal pf Forensic Sciences, #:11-17, No. 1, January, 1959. 29 Lechat discusses an apparatus called the "Hainaut H.S.L." which permits the examination of objects by direct and reflected light; it permits photography of normal Size and moderate magnification as well as micro- photographs. The examinations can be made under infra- red, ultraviolet, white, and sodium light. The British image converter tube type CV1M8 is used in the con- struction of the apparatus. Photographs, electrical circuits, and parts lists are included. Edlin discussed his adaptation of a standard laboratory microscope and an electronic image converter for the direct infrared viewing of specimens. Schem- atics and photOgraphs illustrate the source of infrared radiation, the lens system, infrared filters, the image converter cell, and the high voltage power supply unit. Harrison (9), O'Hara and Osterburg (l8), and Kirk (17) mention in their texts that the electronic image converter is useful for infrared viewing of objects. ll Rene Lechat, "Infrared PhotoscOpy," Inter. Crim. Police Review, 69:170-179, JuneeJuly, 1953. 12 C.H. Edlin, "Infrared Microscopy Using Electronic Image Conversion," Inter. Crim. Police Review, 96:83—88, March, 1956. CHAPTER IV EQUIPMENT AND MATERIALS USED IN THE STUDY I. PHOTOGRAPHIC Camera. A 35mm Exakta camera equipped with a 50mm f/1.9 Xenon lens was used for all of the photography. A Kodak +2 close-up attachment was fitted over the camera lens. This attachment permitted the camera to be placed approximately thirteen inches from the object mounting board. At this distance the image Size of the ink lines on the film was adequate for detecting the presence or the absence of infrared luminescence. The +2 attachment, however, will not provide a sufficiently large film image for most document problems. Attachments ranging from +6 to +10 would be more suitable for actual questioned doc- ument problems. These attachments provide a considerably larger film image and will permit the making of better quality photographic enlargements. The initial focusing was performed by removing the camera back, plaCing a piece of onion skin paper over the image Opening at the film plane, and then moving the camera to and from the object board until the ink lines were in Sharp focus on the onion Skin paper. The lens was set at f/1.9. No filter was on the lens during the focusing. The position of the camera was marked on the table so that the camera could be removed when necessary and returned to 30 31 its correct position without re-focusing. For the actual photography a Wratten 87C filter was fitted over the close-up lens on the camera. The 87C was selected because of its ability to adequately absorb any visible light which was reflected by the paper stock or ink lines. The 87C provides a Sharp transmission cut- off at just below 8000 A. Tests with the 87, 88A, and 89B filters disclosed that they did permit some passage of visible light. (See Figure A for % Transmission vs. Wave- length curves). In instances of weak luminescence, the photographing of visible light could definitely mask the luminescence. All of the photOgraphy was performed in a dark room in order to eliminate all light other than that being filtered by the COpper sulfate solution. The camera lens was set at f/l.9. No infrared focusing compensation was employed. The negative images, even at this maximum lens aperture, were distinct and sharp without focusing com- pensation. Tests with smaller lens openings revealed that the slight increase in sharpness, if any, was not significant enough to warrant the necessity of an increased exposure time. Increased exposure time also increases the possibility of camera movement resulting from environ- mental vibrations; any camera vibration on a 35mm format can nullify the increased sharpness prOvided by smaller lens apertures. A Simple hand magnifying glass was used to view the negatives. 32 Film. Kodak High Speed Infrared 35mm HIR u02 film was used for all of the photography. It was chosen (1) because of its faster film speed (8X that of regular infrared film), and (2) because of its extended sensi- tivity into the infrared range. Regular infrared film cuts off at approximately 8720 A; HIR H02 extends to approximately 9000 A. Exposure Time. Twenty seconds exposure at f/l.9 was used for all of the photography. This exposure combination provided negatives of optimum density. The following procedure was used in order to avoid 'possible camera movement caused by the Opening and closing of the Shutter: A piece of black cardboard was held in front of, but not touching, the camera lens; the Shutter was then opened and the hand removed from the Shutter release; the black cardboard was removed from in front of the lens and twenty seconds were counted off; at the end of twenty seconds the black cardboard was again placed in front of the lens; the Shutter was then closed. Film Developer and Development. Kodak D-76 developer was used. It is the developer that is recom- mended by Kodak for use with HIR #02 film. It provided excellent tonal gradations; accordingly it was capable of revealing the presence of extremely faint infrared luminescence. The use of a contrast develOper such as l 0 "Cine-Kodak and Kodak High Speed Infrared Film," Kodak anrhlet No. M-Q. Rochester: Eastman Kodak Company. 33 Kodak D-19 is not recommended. The film was developed in a daylight developing tank for ten minutes with 10 seconds agitation at one minute intervals. Stop Bath and Fix. A standard acetic acid stop bath and Kodak Rapid Fixer were used. Films were washed for twenty minutes, dipped in a wetting agent bath, and hung to dry without being wiped. II. LIGHT SOURCE AND CuSObf FILTER Light Source. A 35mm Kodak slide projector Mod. 500 equipped with a 500 watt bulb was used. The projector lens was retained because it provided a more concen- trated beam. A Slide projector proved to be the most convenient and efficient excitation source. The built- in fan helped to eliminate the heat problem which is an inconvenient characteristic of photoflood bulbs., In addition, the projector housing eliminated the extran- eous light that is difficult to eliminate when using photo- floods. Microscope and Similar illuminators were found to be inefficient excitation sources because of their low wattage. The various papers which bore the ink lines were taped one at a time on a vertical backboard. The Slide projector was placed at a 95 degree angle to the back— board; the distance from the projector lens to the back- 3” board was 9 1/2 inches. Periodic exposure meter readings were made to ensure that the illumination remained constant throughout the study. The room was totally dark except for the illumination from the slide projector. Copper Sulfate Filter. The filter consisted of a 10% aqueous solution of copper sulfate in a clear, semi- flat sided one pint wine bottle. The liquid light path was 35mm. The filter was placed in front of and in contact with the projector lens. The bottle provided complete coverage of the lens and the light leaks from the lens housing. This filter provided efficient absorption of the infrared that emanated from the projector lens and lens housing. However, it was necessary to eliminate the light leaks from the lamp housing vents. The leaks were elim- inated by covering the vents with a loose fitting box. The box was removed immediately after each exposure was made. This prevented the projector from overheating. The copper sulfate filter did not overheat at any time. Figure 3 illustrates the photographic set-up. Figure 5 illustrates the absorption curve for 10% aqueous cx>pper sulfate in a one centimeter layer. 35 TEST INK LINES I Illllllllllll I g_, to}. Cu 504 I ‘25" +2 CLOSE UP LENS CE! (316 FlLTER L CAMERAE FIGURE 3 DIAGRAM OF PHOTOGRAPHIC SET-UP :11 7 wt! 3 ‘i’ >- C E a C I n i 5’.‘ 8 a 3 a ”n I 0—“ m 0 m 33 3 [RAISIIWAIG mmumu 5 _ 0mm .. § _. MISI" .. 1|)! 0 no son m ”A FIG. R %TRANSMISSION vs. WAVELENGTH; 87,87C,88A AND 898 KODAK WRATTEN FILTERS. (FROM "KODAK WRATTEN FILTERS FOR SCIENTIFIC AND TECHNICAL USE", P. 77) FIG. 5 % TRANSMISSION vs. WAVELENGTH; 10% AOUEOUS COPPER SULFATE, WATER, 50% NICKEL SULFATE. (FROM wALTER CLARK, PHOTOGRAPHY p1 INFRARED, P. R23) 38 III. WRITING MATERIALS Ballpen inks. A total of 92 ballpens or ball- pen refills were used. Each was assigned a number. They are listed in Appendix A. The pens and refills were col- lected in the St. Louis area from users, retail stores, and from a local manufacturer. The predominant color was blue. Red, green, black, and gold inks were also collected in order to investigate more completely the luminescent characteristics of ballpen inks. The total collection was considered to be representative of those inks which might be encountered in the majority of ball- pen ink problems. Liquid inks. A total of 20 bottles of blue and colored inks were collected. Each was assigned a number. They are listed in Appendix B. All of the inks were purchased from local retail stores. Paper stock. A Spiral Shaped line of every ink was placed on each of the following 17 paper samples. The paper samples were cut to approximately 3 x H inches, and could accomodate ten ink lines. 1. White file cards (3 x 5 inches). 2. One brand of safety paper comprised of the colors yellow, green, and blue. 3. One brand of safety paper comprised of the colors yellow, green, blue, pink,and gray. 39 A. One brand of white bond comprised of eight different types. Each of the eight types exhibited a different ultraviolet fluorescence. They were Specif- ically chosen because of this characteristic difference. The purpose was to determine whether or not differences in ultraviolet fluorescence would affect an ink'S infra- red luminescence. The paper samples are listed in Appendix C. CHAPTER V EXPERIMENTAL PROCEDURE The study was organized into Six phases. They were (1) the experimental controls, (2) the photography of unaltered ink lines on the seventeen paper stocks, (3) the photography of eradicated ink lines on the seventeen paper stocks, (4) the photography of erased ink lines on the seventeen paper stocks, (5) the photography of oblit- erated ink lines on the seventeen paper stocks, and (6) the chemical testing of the blue colored ballpen inks for their presumptive constituents. I. EXPERIMENTAL CONTROLS The following control procedures were instituted in order to confirm that it was infrared luminescence and not reflected visible or reflected infrared that was being recorded on the film. (It should be recalled that the image of an ink line which exhibits infrared lumin- escence will be recorded as black or as a shade of gray on the film. Ink lines that are capable of reflecting infrared or visible will also record as black or as a Shade of gray on the film). A representative sampling of those ink lines which exhibited infrared luminescence was selected for rephoto- graphing by the standard infrared photography technique. H0 LII (The film characteristic of the apparent luminescent lines was a dense black, or a Shade of gray that was definitely darker than that of the paper stock). The standard infra- red photographic technique consisted of using an 87C filter on the camera lens, and the Slide projector light source without the copper sulfate filter in front of it. The results of this control photography disclosed that those ink lines which had exhibited apparent infrared luminescence were now recorded as either clear lines on the film, lines that exhibited less density than the background paper stock, or the lines were rendered invis- ible. These are the characteristics to be expected when little or no infrared or visible light is reflected from an object being photographed. II. UNALTERED INK LINES A Spiral Shaped line of every ink was placed on each of the 17 paper stocks. The identifying number that had been assigned to each ink was written at the head of each spiral. The lines were drawn in this irregular Shape in order to evaluate the significance of an abrupt change in directional movement. The lines were then photo- graphed by the experimental technique, and the presence or absence of infrared luminescence was determined by a visual reading of the photographic negatives. H2 III. ERADICATED INK LINES A Spiral Shaped line of each ink which had ex- hibited luminescence was placed on each of the 17 paper stocks. The ball pen ink lines were then eradicated with a saturated solution of calcium hypochlorite. Light rubbing with a cotton tipped stick was necessary to com- plete the eradication. The lines which were drawn with the liquid inks were eradicated with Carter's Rytoff eradicator solution. Except for one or two of the non-blue inks, no rubbing was required. All of the eradicated ink lines were dried at room temperature, and were then photographed by the experimental technique. IV. ERASED INK LINES A Spiral Shaped line of each ink which had ex- hibited luminescence was placed on each of the 17 paper stocks. Some of the lines were erased with a standard ink eraser; others were erased with an electric eraser. Minimal destruction of the paper stock was attempted. V. OBLITERATED INK LINES A Spiral Shaped line of various inks was placed on the 17 paper stocks. Luminescent and non-luminescent H3 inks were used in various combinations. e.g., non- luminescent inks obliterated with luminescent inks, luminescent inks obliterated with non-luminescent inks, inks that luminesced strongly obliterated with inks that luminesced weakly, inks that luminesced weakly obliter- ated with inks that luminesced strongly, and inks Obliterated with an ink of a different color. VI. CHEMICAL TESTS FOR CONSTITUENTS A color Spot chemical test procedure devised by Crown was used to classify each of the blue ballpen inks.l According to Crown, the procedure permits the presumptive detection of various ballpen constituents. After chemical testing, the inks were classified into Specific groups. Accordingly, ink lines from each of the Sixty- nine blue ballpens or refills were drawn on filter paper. Using Crown's procedure, a drop of concentrated hydrochloric acid was added to each line. The resulting color and bleed (if any) was observed and noted. The Spot was permitted to dry at room temperature. A drOp of saturated David Crown, et al., "Differentiation of Blue Ballpoint Pen Inks," The Journal of Criminal Law, Crimin- ology and Police Science, 52:338-3H3, September-October, HH aqueous sodium bicarbonate was added to the test area. The resulting color or colors were observed and noted. The colors were compared with the color reactions as set forth in Crown's scheme; The ink was then class- ified into its presumptive constituent group. Crown's scheme is reproduced as part of Table III. The results of the chemical tests in the present study are set forth in Table III. Crown's original paper provides a comprehensive 2 description and interpretation of the color reactions. CHAPTER VI FINDINGS AND CONCLUSIONS 1. UNALTERED INK LINES General. Fifty-three of the ninety-two ballpen inks exhibited some degree of infrared luminescence. Nineteen of the twenty liquid inks exhibited some degree of infrared luminescence. In addition to the blue inks, some of the reds, greens, blacks, and both golds luminesced. Therefore, the photographic detection technique is applicable to ballpens and liquid inks, and to the variety of colors which comprise them. The intensity of luminescence was arbitrarily categorized into three degrees of film density: strong, medium, or weak. Luminescence was considered strong if it recorded as black on the film; medium if it recorded as a Shade of gray; weak if it was barely perceptible. Experimental photographic technique pp. converter tube technique.- The photographic technique was found to be significantly more sensitive than the image converter tube (sniperscope). Those inks which exhibited a strong photographic luminescence were generally easily detected with the converter tube. However, those which exhibited a medium photographic luminescence were H5 H6 difficult or impossible to detect with the converter tube; inks which were barely perceptible on the film could not be detected with the converter tube. White paper stocks. The eight white bond papers and the white file card revealed no significant differ- ences in their effect on luminescence. Any ink that luminesced exhibited a consistant degree of lumines- cence on all nine of the white paper stocks. As pre- viously stated, each of the nine white paper stocks fluoresced differently under ultraviolet light. Appar- ently there is no correlation between a paper's ultra- violet fluorescence and an ink's capability to exhibit infrared luminescence. At least no relationship was observed in this study. Colored paper stocks. The study disclosed that a colored paper stock can Significantly influence the luminescent capabilities of an ink. The colored safety papers used in this study produced some rather sur- prising results. For instance, ink #6 exhibited medium luminescence on the white stocks, and weak luminescence on Graham blue and Bergstrom yellow; it did not lumin- esce on any of the other colored safety papers. Inks #32 and #38 luminesced weakly on the white stocks, weakly on Graham blue, and medium on Bergstrom yellow; these two inks did not luminesce on the other colored H7 safety papers. Another interesting variation was exhibited by ink #67. It exhibited weak luminescence on the white paper stocks, was rendered invisible on Graham blue and Bergstrom yellow, but recorded as a clear line on the remaining colored safety papers. These examples and many others to be found in Table I clearly demonstrate that inks comparisons which involve colored papers should be conducted on the same brand and color of paper. See also photographs in Appendix D. Visual ink colors. The visual color of an ink provides no indication of the ink's capability to exhibit infrared luminescence. Inks which exhibited similar visual colors or hues were found to exhibit distinctly different luminescent properties. For instance, inks #11 and #12 appeared to be identical in color when viewed under a microscope. However, ink #11 luminesced strongly on all seventeen papers; ink #12 recorded as a clear line on all of the papers. Directional changes pp pen movement. Abrupt directional changes did not appear to alter a ballpen's luminescent capability. Luminescent ballpen lines exhibited no break in luminescence as a result of directional change. Pen pressure did cause a Slight variation in intensity. The influence of pen pressure was noticable with those inks which exhibited weak H8 luminescence. These changes in luminescence intensity could usually be accounted for by visually observing a change in the color intensity of the original ink line. Old pp poorly mixed liquid inks. A most Signif- icant change in luminescent properties occurred with liquid ink #18 (Waterman's Permanent Black). This bottle was purchased from a local stationary store which was disposing of old inks. The bottle had never been opened. As was the case with all of the liquid inks, the #18 bottle was not shaken prior to dipping the pen. An examination of the #18 negatives (white paper series) disclosed that #18 luminesced strongly, weakly, inter- mittently, and not at all. No other inks, ballpen or liquid, had exhibited these extreme differences on white paper stock. A visual examination of the original #18 ink lines disclosed that they were of equal color and density on the papers. Accordingly, the #18 bottle was shaken and lines were re-drawn on those papers upon which no luminescence had been detected. An examination of the new negatives disclosed that #18 now luminesced with no breaks in the line. However, there still occurred distinct changes in luminescence intensity of lines on the same paper. These changes occurred whenW the pen had not been re-dipped frequently. AS before, the visual color intensity of the ink lines was similar u9 on all of the papers. These findings make it definitely conceivable that the liquid ink writing on a document can exhibit extreme variations in luminescence and yet be the same ink. Of course these variations are not likely to occur with fresh ink in which the constituents are homogeneous. The document examiner who is confronted with a liquid ink problem Should exercise considerable discretion and caution when evaluation his luminescence observations. II. ERADICATED INK LINES The attempted restoration of ballpen inks by infrared luminescence was generally unsuccessful. Several attempts at restoration by standard infrared photography were likewise unsuccessful. In almost every instance the ballpen ink lines required rubbing in order to provide a complete eradication. It was found that even the most gentle rubbing with the hypochlorite solution caused excessive removal of the luminescent constituents. Luminescence was detected in instances where visual fragments of the ink lines were permitted to remain. However, the experimental procedure was no more effective than the visual examination under a microscope. No rubbing for eradication was required with the liquid inks. Accordingly, all of those inks which 50 luminesced in the unaltered state could be restored after liquid eradication. Those Skrip inks which con- tained the fluorescing ingredient RC,35 were of course restorable under ultraviolet illumination also. Successful restoration of eradicated inks ulti- mately depends upon (1) the capability of an ink to luminesce and (2) the degree of physical removal of the luminescent constituents. III. ERASED INK LINES Generally, the restoration of the ballpen and liquid inks was unsuccessful. As with the eradicated ink lines, sUccess was dependent upon (1) the capability of an ink to luminesce and (2) the degree of physical removal of the luminescent constituents. IV. OBLITERATED INK LINES The most successful restorations occurred when both the obliterated and obliterating inks luminesced to different degrees. Strong over weak inks and weak over strong combinations permitted satisfactory restor- ations. Failure usually occurred when a non-luminescent ink covered a luminescent ink. No definite rules can be established because of the many interrelated factors which govern the lumin- escence of the inks involved. The color of the paper 51 stock and the luminescent characteristics of the over- laying ink are probably the most important governing factors. Obliterated ink problems, as a general rule, should be more easily resolved than the problems of erasure and eradication. Several of the successful restorations are listed here. #H9 over #13 on Bergstrom yellow safety #HS over #38 on Bergstrom yellow safety #20 over #57 on Graham green safety #38 over #53 on Graham green safety #57 over #20 on Bergstrom blue safety V. CHEMICAL TESTS FOR CONSTITUENTS Following the scheme devised by Crown, the ballpen inks used in this study were found to belong to one of the following seven groups: I. Methyl Violet - Victoria Blue II. Phthalocyanine - Methyl Violet - Victoria Blue III. Phthalocyanine - Victoria Blue - Rhodamine 8 IV. Victoria Blue V. Victoria Blue - Indulin VI. Phthalocyanine - Methyl Violet VII. Phthalocyanine — Rhodamine B An evaluation of the chemical test findings dis- closed that the presence of phthalocyanine apparently contributes to the non-luminescence capability of a 52 ballpen ink. The presumptive presence of phthalo- cyanine was indicated in twenty-eight of the ballpen inks. Only four of the phthalocyanine containing inks exhibited luminescence: #32, #38, #67, #85. Inks #32, #38, and #67 exhibited very weak luminescence; #85 exhibited a slightly stronger luminescence. If phthalocyanine does inhibit luminescence, perhaps its quantitative presence in these four inks was so minimal that the luminescence was not entirely quenched. Thirty-six of the ballpen inks contained the combination methyl violet and Victoria blue. All of these inks exhibited strong luminescence on white paper stocks. If the sampling in the study provided a rep- resentative collection, it would appear that the methyl violet - Victoria blue combination is the most prevalent in current use. Those inks which were classified under Groups IV, VI, and VII did not exhibit luminescence. The results of the chemical tests are outlined in Table III. CHAPTER VIII SUMMARY A non-destructive photOgraphic technique has been presented which permits the detection of infra- red luminescence in ballpen and liquid writing inks. The method, which utilizes Kodak High Speed Infrared film, has demonstrated a superior sensitivity to weak luminescence when compared with results achieved with the electronic image converter or with standard Speed infrared film. Previously reported film exposure times of from fifteen to thirty minutes may be reduced to fifteen to thirty seconds. The study has demonstrated (1) that all colors of inks may exhibit infrared luminescence, (2) that colored papers can significantly influence the degree of luminescence, (3) that an ink will not luminesce on a colored paper if it will not luminesce on white paper, (H) that the UV fluorescent characteristics of a white paper do not affect luminescence, (5) that under suitable conditions successful restorations of erasures, erad- ications, and obliterations may be achieved, (6) that the accurate luminescence comparison of two inks must be made on the same paper stock, (7) that extreme caution is required when evaluating the luminescence of 53 5H liquid inks in comparison problems,(8) that a com- parison of luminescence between two or more ballpen inks may effectively differentiate them, (9) that inks which exhibit identical visual colors may exhibit dis- tinctly different luminescent qualities, (10) that the detection of the presence or absence of infrared lumin- escence can serve as a valuable adjunct to the established non-destructive techniques. BIBLIOGRAPHY BIBLIOGRAPHY lo BOOkS Clark, Walter. Photography py Infrared. New York: John Wiley 8 Sons, 19H6. H72 pp. De Ment, Jack. Fluorescent Chemicals. Brooklyn: Chemical Publishing Company, 19H2. 2H0 pp. Leverenz, Humboldt. Ap Introduction pp Luminescence pp Solids, New York: JOhn Wiley 8 Sons, I950. 569 pp. Pringsheim, Peter. Luminescence of Li uids and Solids. New York: Interscience PublISHErs, I953. 201 pp. 2. Periodicals Crown, David. "Differentiation of Blue Ballpoint Pen Inks," Journal of Criminal Law, Criminology and Police Science, 52:338-3H3, September-October, 1961 Edlin, C.H. "Infrared Microscopy Using Electronic Image Conversion," Int. Crim. Police Review, 96:83-88, 1956. Gosling, J.W. "Photographic Separation of Colored Imprints by Masking Techniques," Identification News, l2:H-10, May, 1962. Harvalik, Z.V. "An Electronic Image Converter and Its Use in Chromatography," Anal. Chem, 22:11H9-1151, 1950. Hoover, Herbert, and MacDonell, Herbert. "Infrared Luminescence Using Glass Filters," Journal p: Forensic Sciences, 9:89-99, January, I965. Kuhn, Richard. "Infrared Examinations with an Electronic Image Converter," The Journal of Law, Criminology and Police Science, H5:H86-H90,—Nov.-Dec., 195H. Kuhn, Richard. "Recent Developments in the Use of Infrared Image Converters," Journal p: Forensic Sciences, H:ll-l7, January, 1959. Lechat, Rene. "Infrared Photoscopy," Int. Crim. Police Review, 69:170—179, June-July, 1953. 56 57 BIBLIOGRAPHY (Continued) 2. Periodicals (Cont'd) Packard, Royston. "Selective Wavelength Examinations Applied to Ink Differentiation Problems," Journal p: Forensic Sciences, 9:1000-106, January, I96H. Somerford, Albert. "Technique of Infrared Luminescence," Identification News, ll:H-6, 10, July, 1961. Stoll, Robert. "Analysis and Identification of Paper," Identification News, l3:H-10, 12, September, 1963. Zyuskin, N.M. "The Luminescence Photography by Ultra- violet and Infrared Radiation," Translated from: Zhurnal Nauchoi i Prikladnoi Fotografii i Kine- matografii 5 (H), 27H-279, 1960. Through courtesy of Eastman Kodak, Rochester, New York; Translated by Carlo A. Bauman. 3. Kodak Publications "Cine-Kodak and Kodak High Speed Infrared Film," Kodak Pamphlet No. M-9, Rochester: Eastman Kodak Co. "Infrared and Ultraviolet Photography," Kodak Data Book, ,Rochester: Eastman Kodak Company. H. Government Publications Barnes, David. Infrared Luminescence of Minerals: Department of the Interior, GeologIEaI Survey Bulletin 1052-C. Washington: Government Printing Office, 1958. CITED REFERENCES 10. 11. 59 CITED REFERENCES Godown, Linton. "Infrared Luminescence." Unpublished paper read at the American Academy of Forensic Sciences, Chicago, February, 1960. Kuhn, Richard. "Infrared Examinations with an Elec- tronic Image Converter," The Journal of Crim- inal Law, Criminology and—POlice SoleHEe, H5:H86-H90, November-December, 195H. Kuhn, Richard. "Recent DevelOpmentS in the Use of Infrared Image Converters," Journal pf Forensic Sciences, H:1l-17, January, 1959. Barnes, David. Infrared Luminescence of Minerals. Department of The Interior, GeologiEaI Survey Bulletin 1052-C. Washington: Government Printing Office, 1958. Thirty cents. Somerford, Albert. "Technique of Infrared Luminescence Photography," Identification News, ll:H-6,10, July, 1961. Gosling, J.W. "Photographic Separation of Colored Imprints by Masking Techniques," Identification News, l2:H-10, May, 1962. Hoover, Herbert, and MacDonell, Herbert. "Infrared Luminescence Using Glass Filters," Journal p: Forensic Sciences, 9:89-99, January, 196H. Osborn, Albert. Questioned Documents. Albany: Boyd Printing Co., Second Edition, 19H6. Harrison, Wilson. Suspect Documents. New York: Frederick A. Praeger,.Publishers, 1958. "Filters and Pola-Screens," Rochester: Eastman Kodak Company, Data Book. Conway, James V.P. Evidential Documents. Springfield: Charles C. Thomas, 1959. 12. 13. 1H. 15. 16. 17. 18. 60 CITED REFERENCES (Continued) Clark, Walter. Photography EX Infrared. New York: John Wiley 8 Sons, 19H6. "Infrared and Ultraviolet Photography," Rochester: Eastman Kodak Company, Data Book M-3, 1961. Packard, Royston. "Selective Wavelength Examination Applied to Ink Differentiation Problems," Journal of Forensic Sciences, 9:100-106, January,_I96H. Lechat, Rene. "Infrared Photoscopy," International Criminal Police Review, 69:170-179, June- July, I953. Somerford, Albert. "Recent Technological Develop- ments in Questioned Document Examinations," Identification News, 13:8,1H-15, Feb. 1963. Kirk, Paul. Crime Investigation. New York: Inter- science, I953. O'Hara, C.E. and Osterburg, J.W. Ap Introduction pp Criminalistics. New York: MacMillan, 1952. TABLE I LUMINESCENCE CHARACTERISTICS OF BALLPEN INKS * GRAHAM SAFETY TBERGSTROM SAFETY ‘ I INK $1165? I YELLOW GREEN GRAY PINK (BLUE YELLOW GREEN BLUE 1 L i L I L L L | L L L “L _ 2 L I L” L L L i L L L L 3 L I L L L L i L L L Lw L 4 L I L ; L i 5;; L: Li L L L 5 = ‘ i f i 6 Ln i T I i Lw _ “Lu 7 i I ’ 8 Z A 9 Q ’ 10 5 I _ 11 L 3 L L I L L L L L L 14 5 i i 15 16 —— 4 I17 L 1 L Lm L Lw L L Lm L 18 L i L L L L L L L L 19 i _____ ____ _ 20 L i L L L Lw L L L L 21 22 L L L L L Lw 23 L L L L L L L L L *L denotes strong luminescence Lm " medium " Lw " weak " 61 Empty box denotes no luminescence detected 62 TABLE I (Continued) LUMINESCENCE CHARACTERISTICS OF BALLPEN INKS WHITE GRAHAM SAFETY 'BERGSTROM SAFETY NK STOCK YELLOW GBEEN GRAY BINLBLUE YELLOW GW 24 25 26 27 L L L L L L L L L 28 I I I- 29 L L L I L Lw L L Lw L 30 L L L I L L L L L L”_ 31 32 Lw I Lw Lm 33 34 i 36 I W“ _______t __ 37 L Lm Lw Lm Lw Lm L Lm Lmd 38 Lw Lw Im_ 40 41 L L L L L L L L 42 L L L L L L L L 43 44 L L L L Lw L L L L 45 I __________ I” H a 46 Lw __r __ __ _ Lu" _wm _“”~ 47 L L L L L L L L ""1 48 63 TABLE I (Continued) LUMINESCENCE CHARACTERISTICS OF BALLPEN INKS WHITE STOCK t; t I i I GRAHAM SAFETY ? [YELLOW GREEN GRA Y PINK 131;; g Lw Lw BERGS TROM SAFETY illiénLjfiflgflljfllfliq Lw Lw 49 L Y t—j L 5 L L L m..- -———.. w. 50 51 -— 1—”fi*—— ‘1? I 2t"t" I I I t“ L i L L p . -—-—-____.—__-._. ,P Lw Lw 54 3 L L _uL_;LLn--iLL;-- L L 55 L L L LLLL ._____L L 56 A I ; 57 Lw ; : A- C? Lw Lw Lw 58 Lu ____- ' LwL L L L 59 L L L "'11“ L -L - [_L if _ L_ L L 60 Lw i i L" 51 g " ‘ ” ‘ ‘ 62 L 3 L L 4 L L->? Em“ ___Ew-_LPH- 63 66 Lm 67 Lw 64 Lm j L Lw g L Lw E L 65 L j L L ? L L i 1 ”f L Lw Lw 68 69 70 .——__ —— -1»— __.-..-.._._--_ __4r—-——..-.—._...—.— 0—.——————.——.- 64 TABLE I (Continued) LUMINESCENCE CHARACTERISTICS OF BALLPEN INKS BERGSTROM SAFETY .__.-.' _— b— -—.-_.--.___..——{>—-—--————-— ..1 GRAHAM SAFETY !WHITE¥77 ___ —— _- -4.-- _. __..-__ _.._-- I L by». L III—9“; l. I.“ II. Ilflt."4' 1" IL. 1 L _. ~.1---.-‘——-———.— 4-. .-._. .. .. >v_.-.,..__-__.- _- ” a _ _ L . _ I I _ m r. iJla’JI. .IIL. _ L _ ._ 4L _ I- ..-... m . _ N p M _ _ F 4 -7 4p— __.——._—.———— _ _ _ . _ I _ u I . p 4 Lw I 312091;: imJow GREEN GRAY - PINK BLUE YELLOW GREEN BLUE 71 72 73 74 75 76 77 78 79 81 82 83 84 85 86 _..._--—_-_-__(...._-......_._.-..}_._._.___.-. I . -I...-._._ _. ‘ ——_____.. _ _ _. _ . v . 1 87 88 89 90 91 92 TABLE II LUMINESCENCE CHARACTERISTICS OF LIQUID INKS cu. ' BERGS TROM SAFETY GRAHAM SAFETY C WHITE 10 11 12 13 14 15 16 2O M. w mw m . w mmwm “w I m m L Lm .L L m m m L L L _L m .L_ L _n - I Sui... m I N I w . m LIw m . w I m. L. L L L L L _L “L L ML L _ u _ . G --.__I..-_.--.-T--_ if. I _ I a I w I I _ III-1 III--- . I _. . o m _ _ u M _ _ u _ _ I _ _ _ .I I m .w. m_ _ u _ m ,L Iran .7“ Tu erTunry Tamra .L Tu “Tu In” H.LW.L _ u _ W _ m _ I I . _ m _ m I m _ m E. M I. I .---_-::--.. -I- L- I _ I . .. U m: m "mw I w mm“ L _ mi w” _u LLI .L.LHL.L L..L.L LLI LLIL LWL LILWL L I 4 u, I I L w H t. .M T -_..-..--I-T--..r.-I+II IIIEW- .. m mm: M uww_w.. .wm mm “wwn _ _m H “LN ,LLLMLL .L“ “mm ”L LI .LWL "m _ . _ _ . . _ . ._ _ .. .- . w 4. m * . 4IM .__ I_.I h .im ._-I-. 4 mm m_ M W U m I _ M " mm . - --L m GL _Lm ML L_L_LUL L MLWL LWL L" LIL m - I p .w . M. . I If I I: I I” lilyll Ill-TIIIIIIIIIH ._ J N m M m __W W. W W m. “W W“ .mU _ m; “mm LLWL Lme L L” L L” ”L.L I . I _ . . m _ . _ _ I m G-- L I __ III-Ii L I I _ m w _ I I I m I 0 w . _ . m: I I I mL ML L_LLLWL L LMMLL_ “LML _ w m m m m I I .«I III, 4‘ I if- ‘ .III [a _ K. _ _ I C _ m m m _ m L WL L L L L L L L L L L L L L L L L K m 65 TABLE III "SCHEME FOR THE PRESUMPTIVE IDENTIFICATION OF BALLPEN INK FORMULATIONS" (after Crown) "The ink line is spotted with concentrated hydro- chloric acid, using a micropipette. The color of the ink line itself and the color of the "bleed", if any, should be observed. When necessary, the hydrochloric acid spot should be absorbed on filter paper and neu— tralized with saturated sodium bicarbonate solution, and the resultant colors observed. A second Spot should be made on the ink line with N,N-dimethy1form- amide (or other solvents which release the red dye) and then observed under ultraviolet light, either short or long wavelength. All hydrochloric acid spots on the document itself must be neutralized afterwards, to pre- vent damage to the document. Should aberrant reactions be encountered, conventional chromatography, followed by spot testing, should be employed. 1. Non-phthalocyanine Inks-~absence of greenish or olive color on ink line; no fluorescence. a. Indulin and Victoria b1ue--purple ink line. b. Iron blue and methyl violet--positive iron test with KCNS. 0. Victoria blue--absence of violet coloration after neutralization. d. Victoria blue and methyl violet--vivid violet coloration after neutralization. 66 67 TABLE III (Continued) Phthalocyanine Inks--greenish or olive coloration of ink line. 2. Presence of rhodamine B--bright pink fluores- cence. e. Phthalocyanine and rhodamine B--no blue or purple colors after neutralization. f. Phthalocyanine, Victoria blue and rhodamine B-- purple, blue, and red colors after neutral- ization. 2. Absence of rhodamine B--no pink fluorescence. 3. No bleed in HCl. g. Phthalocyanine and alkali blue. 3. Bleed in HCl. h. Phthalocyanine, Victoria blue and alkali blue--no violet coloration after neutral- ization. i. Phthalocyanine and methyl violet—-pale green ink line, pale yellow bleed. j. Phthalocyanine, methly violet and Victoria blue--brownish bleed, violet color, after neutralization. 68 TABLE III (Continued) CLASSIFICATION OF BALLPEN INKS INTO DYE CONSTITUENT GROUPS The chemical tests indicated that each of the sixty-nine blue ballpen inks could be classified into one of seven dye constituent groups. The Specimen number of each ink is listed under its respective group category. Inks which exhibited luminescence are parenthesized. I. METHYL VIOLET - VICTORIA BLUE (l) (27) (54) (79) (2) (29) (55) (81) (3) (30) (62) (82) (H) (37) (6”) (86) (11) (Al) (65) (87) Total 36 (17) (AZ) (66) (88) (18) (50) (75) (89) (22) (51) (77) (90) (23) (53) (78) (91) PHTHALOCYANINE - METHYL VIOLET - VICTORIA BLUE 10 (32) 69 12 33 70 la (38) 71 15 39 72 Total 21 19 no 80 25 52 (85) 28 61 92 16 .36 (67) 7” 83 III. PHTHALOCYANINE - VICTORIA BLUE - RHODAMINE B Total 5 69 TABLE III (Continued IV. VICTORIA BLUE 21 31 35 73 V. VICTORIA BLUE - INDULIN (H9) VI. PHTHALOCYANINE - METHYL VIOLET 9 VII. PHTHALOCYANINE - RHODAMINE B 26 Total n Total 1 Total 1 Total 1 APPENDICES APPENDIX A LIST OF BALLPENS EXAMINED Trade names have been listed only in those instances (1) when the refill bore identifying markings, (2) when a pen was known to contain its original refill, (3) when a pen was a non-refill type. All other pens or refills are listed as "No name." Pens or refills other than blue are so designated. Specimen Specimen 1. Rocket 29. Ritepoint refill 2. Wonder-Rite 30. Fine Riter 21 refill 3. No name 31. Paper Mate 19 refill u. Herald Square 32. Sheaffer's 303 refill 5. Herald Square (black) 33. Scripto refill 6. Herald Square (red) 3”. No name 7. Herald Square (green) 35. Paper Mate refill 8. Wonder-Rite (green) 36. No name 9. Wonder-Rite (black) 37. No name 10. No name 38. Sheaffer's 303 refill 11. No name 39. Ritepoint 201 refill 12. No name no. Ritepoint 353 refill 13. Ready Riter (black) H1. Ritepoint 90H refill 1”. No name “2. Ritepoint 800 refill 15. Sheaffer's refill H3. Ritepoint 120 refill(black) 16. No name nu. Ritepoint 32H refill(red) 17. No name H5. Ritepoint 285 refill(green) 18. No name ”6. Ritepoint refill(gold) l9. Scripto T-OlO H7. Topriter refill(green) 20. Utility Pen (red) #8. TOpriter refill(red) 21. Paper Mate C2 refill us. Topriter refill(black) 22. Dixon Non-Skid Ball lRB 50. Topriter refill(blue) 23. No name 51. Wearever refill 2H. Carter's Laundry (black) 52. Arnold PR92M refill 25. Scripto 0517AJ refill 53. Alco refill 26. No name 27. No name 28. Ritepoint refill 71 72 APPENDIX A (Continued) Specimen 5H. Alco refill 55. Alco refill 56. Alco refill (black) 57. Alco refill (red) 58. Ready Riter MAO (red) 59. No name (green) 60. Ready Riter 5H0 (gold) 61. Ready Riter lUO (blue) 62. No name 63. No name (red) 6”. No name 65. No name 66. No name 67. No name 68. Eversharp KECSH refill (black) 69. Eversharp KECSH refill (blue) 70. Steno-Pen “67F 71. A.T. Cross X-Med.u refill 72. A.T. Cross R—Med.8 refill 73. Paper Mate El refill 7H. No name 75. No name 76. Utility ROOM (green) 77. No name 78. No name 79. No name 80. Scripto Tele-Gauge refill 81. No name 82. No name 83. No name 8H. Ready Riter 332 (green) 85. Gold Bond Kushion Karbide refill 86. No name 87. No name 88. No name 89. No name 90. No name 91. No name 92. No name APPENDIX B LIST OF LIQUID INKS EXAMINED Skrip Permanent Blue-Black #22 Skrip Permanent Jet Black #32 Skrip Washable Blue #uz Skrip Permanent Royal Blue #52 Skrip Washable Black #62 Skrip Washable Purple #82 Rose #Iou Violet Green Cardinal Red Washable Royal Blue Blue Black Dubonnet Brown Carter's Permanent American Blue Waterman's Permanent Black Parker Super Quink - Permanent Blue Specimen l. 2. 3. H. 5. 6. 7. Skrip Persian 8. Sanford Penit 9. Sanford Penit 10. Sanford Penit ll. Sanford Penit 12. Sanford Penit 13. Sanford Penit 1A. Sanford Penit 15. 16. Carter's Violet l7. Carter's Brown 18. 19. 20. Parker Super Quink - Permanent Blue Black 73 APPENDIX C LIST OF PAPER STOCKS I. SAFETY PAPERS Bergstrom Private Design Safety Paper. Yellow Green Blue Graham Exchange Safety Paper. Yellow (Primrose) Green Blue Pink (Rose) Gray II. WHITE BOND PAPERS Graham #20 Bonds. Paper 1. Old Deerfield Paper 2. Ezerase Paper 3. Miller Falls Opaque Parchment Paper A. Oriole Linen Paper 5. Crane's Crest Paper 6. Monetary Paper 7. World Paper 8. Requisition 7n APPENDIX D PHOTOGRAPHS Unless otherwise specified, the photographs that follow were exposed on Kodak High Speed Infrared Film for 15 seconds at f/l.9; develOpment time was 10 minutes in Kodak D76 at 68 degrees P. All of the enlargements were made on the same contrast grade of paper. Four blue ballpen inks were selected to demon- strate strong luminescence, medium luminescence, weak luminescence, and non-luminescence. Their identify is as follows: 1. John Williams -- strong luminescence Specimen #1, "Rocket Pen" medium luminescence Specimen #51, "Wearever" refill 2. Ruth Roberts weak luminescence Specimen #32, "Sheaffer's Dokumental 303 Skrip" refill 3. Dell Andrews u. Donald Collins - non-luminescence Specimen #61, "ReadyRiter 10M Pen" The ink specimens were used to write the four names on a white file card and on each of the eight colored safety papers. The paper stock can be ident- ified by the typewritten name and color which appears in each photograph. 75 76 APPENDIX D (Continued) In comparing the photographs that appear in Appendix, the reader's attention is directed to: a) Figures 7 and 8. Note that "Dell Andrews" exhibits luminescence in Fig. 7; it does not exhibit luminescence in Fig. 8 which was made with an 89B filter. This quenching of luminescence might be attributed to the reflected visible light that the 89B filter transmits. (see Fig. A for the transmission curve of the 898 filter). b) Figures 9 through 13 which comprise the Graham Safety paper series. Note that "John Williams" and "Ruth Roberts" exhibit luminescence regardless of the color of the paper stock; the luminescence does vary in intensity; however, "Dell Andrews" exhibits luminescence only in Fig. 9 which is the blue paper stock. c) Figures 13 and 1%. Note that these two safety papers of similar color (yellow) but of different manu- facturer produce a divergent luminescence effect in the "Dell Andrews" signature. "Dell Andrews" does not luminesce in Fig. 13 (Graham Safety); "Dell Andrews" does luminesce in Fig. l“ (Bergstrom Safety). The lumin- escence characteristics of the four inks on the Berg- strom yellow safety paper are similar to their lumin- escence characteristics on white paper stock (Fig. 7). 77 APPENDIX D (Cbntinued) d) Figures 15 and 16. Note that "Dell Andrews" in Fig. 15 has been rendered almost invisible. In Fig. 16 the "Dell Andrews" signature is distinctly readable. e) Figure 17. Note that the absence of the copper sulfate filter at the light source results in the elimination of luminescence. Figure 17 illustrates the results of the standard infrared photographic technique. f) Figures 18 and 1“. Here again is illustrated the elimination of luminescence in an ink when the 898 filter is used. Note that in Fig. 1a, which was photographed with an 87C filter, the "Dell Andrews" signature exhibits luminescence. In fig. 18, which was photographed with an 898 filter, the "Dell Andrews" signature does not luminesce. The series of photographs illustrates: a) That colored paper stocks can affect the luminescent capability of an ink; b) That the luminescent capability of an ink can be controled by the type of infrared transmitting filter used for the photography; c) That blue ballpen inks may be differentiated by means of photographing their infrared luminescence characteristics. REIT; 1‘th LAI'LI) l . /, ,./"(,,/_, (VI/1W4“ 2. ( —/ fi/ :: 3 ° (Ll/fl? Kama“... n x; ‘ 4 A9 /' 424 ° flm/ /‘ Cw etc-24.22 FIG. 6 THE FOUR INKS AS PHOTOGRAPHED WITHOUT FILTERS ON A PANCHROMATIC, TYPE B SENSITIVITY FILM CPOLARIOD 4X5 TYPE 55 P/N, ASA 50) LIL FIG. 7 87C FILTER COPPER SULFATE FILTER FIG. 8 87B FILTER COPPER SULFATE FILTER 7. SECONDS @ F/1.9 FIG 9 87C FILTER COPPER SULFATE FILTER FIG. 10 87C FILTER COPPER SULFATE FILTER FIG. 11 87C FILTER COPPER SULFATE FILTER FIG. 12 87C FILTER COPPER SULFATE FILTER 4 ~. ‘1 _‘7 f FIG. 13 87C FILTER COPPER SULFATE FILTER 87C FILTER Conn: . R S'JLFATF EI LTER I ~‘1DH .. 1 $ ' f 8...».-. ,--¢ 0 -o.” . A ‘ . T I ' '- J‘OCLJ' .— ‘ V ‘ ‘4 ‘ ‘ _ v.-—— FIG. 15 87C FILTER COPPER SULFATE FILTER - FIG. 16 h-o-«I toned I . .' . D 0 . O 87C FILTER COPPER SULFATE FILTER 87C FILTER 17 FIG. NO COPPER SULFATE FILTER 1/50 SECOND @ F/1.9 FIG. 18 898 FILTER COPPER SULFATE FILTER 2 SECONDS 8 F/1.9 T . 3w,\_‘.r§~z“ 1 : {'H—W 11.41.28» 11.1.»; Sham BERGS TRUI‘I YBLL‘U If 1. 2.1 '."/ r Vt] /‘ 'f { ° JU 627K /[/(4:£L 7/ r" ‘1 ' i/m (4/ ;/ (xvi/[way SERRA); 13’] N h 7', .‘. (l / /' /, «’/ {A}? 1% GRAHAM CLAY Gx—v‘mu‘m mac :4 / GI 11. i LA 1‘ G 3 Mr; N thlhf‘. 1': ii Li f .:. . / ’ , /‘/ £71»: ~ C \L ,- (“[95 ‘9‘") 15‘3" I f / // 7/ l}: ?~.///{ I a—w VLJ/x y U “ML. ”LL/Cé/uo Wed“ 1' -14 w" .m‘f. *. f,’\',T ‘- . u .1- .L .L L»! LL/i‘c u