Medical Uses Of Infrared Photography Cultural Studies Essay

Medical Uses Of infr bed radiation emission Photography Cultural Studies EssayTattoos have been an invaluable method for the identification of non skeletonised remains. The throw and/or location of the stain depose be substantially exclusive to provide adequate identification, and especially when combined with other distinguishing features they can definitively let out and individual.During an autopsy the pathologist depart take note of tattoos just as they would any other distinguishing marks, such as birth marks, defects or scars. In cases such as mass disasters, it can nigh cartridge holders be one of only few methods available for the initial tryout of the remains. In 2001, Kingsholm et al studied some(prenominal) nameless bodies and remains plant in Danish waters, some of which had tattoos. Disco very and detailing of any tattoos can also aid in tracing unidentified bodies back to their cultural backgrounds, thus in some cases tattoos have important historical as pects.Tattoos can also indicate a history of incarceration (Mallon et al 1999) and in such cases the individual sporting this unique design may not wish to be easily identified. Repeat offenders for example, may choose to come to or alter their defining features and members of gangs or organised crime groups may wish to no pertinacio employr be associated with that particular faction. Some tattoos may take to heart to connect one individual with another, such as love tattoos, which can also aid in identification of the individual sporting the design.Different shed light on sources and perk up techniques have been apply routinely in criminal investigations the following holds of infrared light (IR) picture taking handed in this introduction are all relevant to this take up as they go some length towards explaining the nature of infrared and thitherfore what might be expected, allowing for deduction of a hypothesis which is presented later in this report.Infrared describes the part of the spectrum just beyond the apparent red wavelengths (700 1200 nm)There are many utilize of infrared hity spanning many divergent fields.For art picture taking purposes, Infrared can be used to motion picture objects in the distance, or in foggy conditions overdue to the infrareds ability to penetrate the haze (Milsom 2001). For portrait picture taking, infrared is sometimes favoured to give the get alongance of a clear complexionInfrareds (IR) ability to penetrate the superficial layers of the epi dermis of skin is exploited in medical photography as a method of photographing venous patterns belowneath the skin and of documenting healing under lesions in the skin. They set in motion that imaging in the heart felt up-infrared range provided relatively grave contrast of subcutaneous veins. This works due to the fact that haemoglobin is a chromophore that drags near infrared, and the skin ties very little IR relative to the absorption of infrared demonstra ted by the veins (Haxthausen, 1933), or transmits or reflects most of the near infrared spectrum, and so it appears lighter by contrast to the Acheronianened veins.Zharov et al (2004) identified the potential difference of this technique as a diagnostic method for varicose veins at a astuteness of 1-3mm into the skin.The use of infrared photography for the let onion of varicose veins or any other subcutaneous abnormalities is demonstrated by Marshall (1981). This research uses infrared reflectance (as well as ultraviolet) to measure the densities across pigmented lesions of the skin and undercoat it to be a useful method.The study by Haxthausen (1933) found that for documenting superficial afflictions, such as psoriasis, ordinary photography was far superior to infrared photography, as under the infrared conditions, the imperfections were removed. Afflictions that occurred in the deeper layers of the skin were captured best apply infrared photography.In cases of burn injury i s can be difficult to measure the misemploy or the thermal burn depth. Anselmo et al (1976) found that infrared photography could be used as a valuable and non invasive method of assess burn depth. Their try used Wratten 89A infrared filter Infrared photography allowed for the differentiation betwixt viable and necrotic dermis.Infrared photography of bloodstains and Gunshot counterweightForensic applications of infrared photography include detecting gunshot residue on habiliments (Bailey et al 2007) and less commonly, for detecting bloodstains on dark textileing or at crime scenes. A report by Raymond and Hall in 1986 illustrated a dark falsifyed sofa, showcased in the report as a barren and white photograph for the visual spectrum comparison. In this photograph there is no obvious bloodstain, it cannot be rarified from the rest of the sofa due to the dark colour of the sofa. The infrared photograph was taken using the Wratten 88a filter. In this photograph the sofa had li ghtened and now by comparison, the r each(prenominal) of bloodstained sofa (now darkened by contrast) could easily be distinguished.When using infrared photography to detect and document traces of blood on dark clothing, the infrared will make the blood appear darker and the environ clothing appear lighter by contrast. This is all due to the sorb capabilities of the clothing and of the blood. Blood absorbs throughout the overt spectrum and the near infrared spectrum (typically entrancing most wavelengths of near infrared 700-900nm) and so its appearance in infrared records will be darkened, in contrast the clothing might only absorb through the visible light range of the spectrum, and so in the infrared records will appear lighter, or transparent.Dark clothing can hinder the victorious visualisation of blood spatter patterns in much the same way that darkened mummified skin can hinder the perception of tattoos, or that charring on a fire damaged document can affect the succe ederful visualisation of the piece. A study by Perkins (2005) used digital infrared photography, Wratten 89B filter to photograph blood spatter on some(prenominal) different materials. The dark clothing appeared to reflect the infrared, thus enhancing the contrast between the clothing and the blood patterns.Bailey et al (2007) used digital infrared photography to better visualise gunshot residue on dark clothing. It is very similar in twain methodology and results to the use of this technique in bloodstain analysis. The tv camera ISO was set at 200 and the filter used was the Wratten 87. The GSR, undetected under visible light conditions, appeared dark against a lightened cloth under IR.The use of infrared in analysis of obliterated writings and questioned documentsInfrared photography also has many applications in the field of forensic comprehension.It is a common method for detecting obliterated writing (Creer 1976) for detecting forged, or altered documents, such as cheques a nd to aid in the test of writing obscured by charring on fire damaged documents (Bartha. 1973)McCaul et al (2007) discuss the problems facing forensic scientists when traditional photography techniques fall short at documenting certain evidence. In the examination of documents, IR can be used to detect forgeries or alterations, relying on the fact that the visually similar signs may reflect or absorb infrared at varying levels and wavelengths.Parallels can be drawn between the uses of infrared for examining obliterated writing and this study into examining master tattoos from underneath span tattoos. The use of correction fluid or other inks to move through writing serves to render the profound text illegible, in the same way that the cover tattoo serves to distort, hide or in all cover the schoolmaster profound tattoo. If infrared photography can allow for the underlying writing to be visualised, than it is goodly possible that underlying lord tattoo could be recovered. The successful recovery of obliterated writings is dependent on the different inks used and their infrared sorb capabilities. Some ink, when irradiated with infrared, will absorb it. This is due to the presence of different Chromophores in the different inks (Ellen, 2006)A chromophore is the chemical group of a molecule that is responsible for the molecules colour, and they absorb, reflect and transmit different wavelengths. opposite examples include chlorophyll, melanin and amethyst.Infrared photography can also be used to examine/restore writing on charred documents (Bartha 1973). The success of the visualisation is dependent on the degree of charring. The charred composition is darkened due to partly converted resinous material before being wholly degraded to elementary carbon. The carbon in the pen ink absorbs the infrared and so appears dark under IR, by contrast the charred paper looks lighter. The Video Spectral Comparator (VSC) is often used in the examination of obliter ated writing (G M Mokrzycki 1999). The VSC uses Infrared radiant energy and filters to see through inks and other obliterations, and reveal obscured objects. The use of infrared photography is not an rarified method for visualising and recording obliterated writing, S. Sugawara (2004) discusses the use of both near and middle infrared in deciphering obliterated writings by tone at writing do by 101 different pens.Erasures describe inks that have been made invisible by removal of the colour components of the inks. Sometimes when these components are removed, remnants are odd behind. Sometimes whatever remains on, or just below, the surface can be detected using infrared. This is the same principle encountered in a paper by McKechnie et al (2008) in which infrared was used to detect remnants of ink left behind in the skin post-laser removal treatment. The findings of this research will be analysed in greater detail later on in this research paper.Other uses of infrared photography The uses of Infrared photography do not jump and end at medical and forensic uses however, for example, Bridgeman and Gibson (1963) used infrared to examine paintings.A paper by J R J Van Aperen De Boer (1969) successfully applies Infrared Reflectography to view the under-drawings of carbon pencil, with varying degrees of success of medieval paintings.Pencil lead (which is primarily graphite) absorbs throughout the infrared range of the spectrum, and the visible range. Because of this, under both near and far infrared conditions the graphite will remain as right away viewable as to the naked eye.Thus far this project has looked at both medical and forensic uses of infrared photography, many of which have in common the idea that infrared can be used to recover, or detect traces of one material (for example ink) from underneath another material (such as correction fluid). These underlying or otherwise camouflaged materials are not readily viewable with the naked eye, or easily recor ded using ordinary photographic methods. This is the same principle as is to be employed in this research.The detection of latent residue tattoo ink pigmentsThe use of infrared photography to record tattoos is by no means a recent phenomenon. As long ago as 1938 Jrg used infrared photography to detect tattoos that were otherwise undetectable with the naked eye.Although infrared photography has been utilized to study tattoos, there is not a great deal of literature available on the topic. Below some specific examples are given. The following are 2 examples found provide useful validation of infrared penetrating capabilities coupled with its specific use for detecting tattoo designs that have been affected by environmental conditions, or purposefully made difficult to visualiseMckechnie et al use infrared photography to attempt to visualise latent tattoo ink residue from laser removed tattoos.This research article only used 2 participants, and with a success rate of 50% and so a follo w up experiment would be required using a larger sample size to validate the findings. Both participants had their tattoos removed by laser treatment to the extent that they were no longer visible to the naked human eye. One of the participants tattoos was professionally do the other was an amateur tattoo. Although the authors explain the difference between amateur and professional tattoos as a possible factor (that is that professional tattoos use more ink and are injected deeper into the dermis than amateur tattoos) and cross reference it with infrareds ability to penetrate the skin, they do not expand on the colour or pigment as being factors resulting in the success or failure of the trial.Visualising tattoos on mummified remains using infrared photographyOne of the original journal articles of interest that could be said to have initiated the archetype behind this project idea, or at the very least inspire a belief of the success of the project, uses infrared Reflectography t o examine tattoos on mummified remains, the mummified tissue normally being darkened to the extent that visualisation under normal photography conditions is near impossible (Alvrus et al 2001) It showcases the usefulness of infrared for lightening certain aspects of a subject in order to see others. In this case, the darkened mummified tissue made it difficult to visualise the tattoo under normal photographic conditions (visible light). Under Infrared conditions however, the contrast between the tattoo and the surrounding skin was enhanced the darkened mummified skin appeared lighter, and by contrast the tattoo (which appeared darker) was readily visible. This is due to the differing absorption/reflection of infrared. The substances in the tattoo absorb the bulk of the infrared the surrounding skin reflects the infrared.A similar technique is used in the identification of tattooing on a 1600 year old mummified physical structure found in Alaska (Smith and Zimmerman 1975) Tattooing was identified on the hands and forearms of the Eskimo female remains using infrared photography. The darkened skin obscured the tattoos to the extent that they could not be viewed under visible light spectral range photography.Skin onerousness as a factorOne of the other variables accounted for in this project is the area on the body of that tattoo, the thought behind this being that the thickness of the skin might come into play. According to E J Wood (1985) the thickness of the epidermis ranges from 0.06 0.1mm (from eyelids, to back and callused areas, respectively). The dermis ranges from 2 4mm thick, and accounts for the bulk of the skin. Although any differences in skin depth tend to be minute, they may still account for variable success rates due to the migrating nature of tattoo ink through the dermis and the penetrating capabilities of infrared. A skilled tattooist will not allow the needle to penetrate the skin no deeper than 2mm, the reasons for which are discussed bel ow in The tattoo shape. The ink must be deposited deeper than the epidermis, or else the ink will fade as the outer layers of the skin shed, therefore the thickness of the epidermis will affect how deep the ink must be deposited. It is also assumed that the thickness of the dermis will correlate with the thickness of the epidermis. This is why this research paper has chosen to look at the area on the body of the tattoo as a possible factor.The tattoo processThe process of tattooing involves injecting pigment, suspended in a carrier, through the epidermis and into the dermis of the skin, no more than 2mm or else the tattooist risk the ink bleeding, creating a smudged effect, regardless of the tattoo technique employed (the settings of the modern tattoo machine do not allow for the needle to penetrate any deeper than 2mm). There is no exact science as to the pressure exerted on the needle by the individual tattooist, as it is a matter of personal judgement (direct quotation from Mark tattooist from Dannys tattoo studio in Sneinton, Nottingham) depending on the area of the body on which the tattoo is being performed. Tattooing on an individuals back or upper arm will require greater pressure because the skin is much thicker, the setting of the tattoo machine will also have to be altered for deeper penetration through the epidermis and into the dermis. at one time injected into the upper layer of the dermis, the pigment is suspended in the fibroblasts (Sperry 1991). When looking at a tattoo, the tattoo is being viewed through the epidermis.Over time the deposited tattoo ink will disperse deeper into the dermis, and so it is possible that time, both between original and cover, and time since cover, could be a feature in the investigation.Tattoo Ink pigments more than often than not, the tattooist will use a tattoo ink containing pigments which will be manufactured outside of the tattooists own premises, the exact content and purity of which is in most cases, unk nown. There are certain guidelines in place for manufacturers of tattoo inks to abide by when producing the inks, however manufacturers of tattoo ink are not squeeze by law to disclose the ingredients used in the inks. A study by Timko et al (2001) found that, of 30 inks studied, the most commonly identified elements were aluminium, oxygen, te and carbon at 87, 73, and 67 percent respectively.Professional tattoo artists have access to over 100 different colours (Kirby et al 2005), many of these are mixtures of colours, for example red and white to make pink, thus making it difficult to classify pigment-wise. The research by Kirby et al (2005) found significant variability in pigment cluster sizes in professional tattoos, compared to amateur tattoos. They also found colour pigment granules to be larger than black pigment granules.This was initially an area of interest, but not one that this research paper will focus on due to the difficulty encountered in obtaining the relevant info rmation.This study uses infrared photography in an attempt to visualise an original tattoo from underneath a cover tattoo, the success of which could be due to a number of different factors. A summary of these factors are as followsTo look at the colours used in both the original tattoo and the cover tattoo and how this affects the successful visual percept of the original tattoo using infrared.To look for any correlation linking time since cover tattoo (up to date of photograph) and success of the experiment. This essentially will be looking at the effects of the migration of tattoo ink.To look at any trends involving time elapsed between original tattoo and cover tattoo, and the success of the infrared photographs obtained. As above, this will be examining the effects of ink particle migration.To look at the area on the body of the tattoo and discover if there is a blood between this and the success of a particular photograph. Essentially, this is investigation skin density as a factor.Taking into account all the research discussed previously and the results obtained by the various studies in the field of infrared photography a few hypotheses have been deducedThe first of all is that the penetrative nature of infrared suggests it is possible to recover the underlying pigment of the original tattoo from beneath the cover tattoo. The reasons behind this are thought at this stage to be due to the colours present, or possibly even the c formerlyntration of black used in the colour mixtures.The way in which an object appears when photographed using infrared is a direct consequence of their absorbing capabilities.For the purposes of this particular study inspiration was drawn for the research into questioned documents, or more specifically the detection of different inks using infrared. Most inks have different absorbing capabilities, some will only absorb through the visible light spectrum, and some throughout the visible light and into the infrared range. The reason behind this, as mentioned earlier, is due to the chromophores in the dye molecules.In the same way that infrared might be used to detect the underwritings of obliterated text, IR could be used to detect the underlying tattoo pigment, depending on the chromophores, or colours used.The abet hypothesis is that any variation in the depth/thickness of the skin will be such a minute difference that it is un seeming to affect the overall success of the project.The factors of time (time between original and cover, and time since cover) are likely to have minimal effect, if any, on the successful visual recovery of the underlying tattoo. It is thought that any trends are more likely to be observed in the extreme time periods, for example, between tattoos that are under a year old and tattoos that are over 30 years old. This is because the most recently done tattoos will not have been affected by migration, whereas very aged tattoos will have undergone decades of migration of the ink particles.Method and materialsA sample number of 33 (n33) individuals were used in this research, all of whom volunteered their time and consented for the presentation of their tattoos anonymously in this research paper. All that was required of potential participants was that they had a cover tattoo, there was no other criteria selected for, for example age or gender. The participants were then required to get hold of out a consent form, as no photographs could be taken without. The participants were asked to fill out a short questionnaire to aid in investigation of the various factors discussed in the introduction, an example of which can be found in the appendix.This project utilizes the near infrared part of the spectrum (the far infrared part of the spectrum is commonly used for thermal imaging). The infrared filters allow infrared light to pass through the camera and blocks most of the visible light spectrum.The Fujifilm IS pro digital SLR camera is sensitive to both ultravi olet and infrared light between 380nm and 1000nm.Optimum settings for the camera were assessed during several pre-experiments. Manual setting, ISO 200 and aperture f/6.3, which provided adequate depth of field for the infrared photographsFilters 87 and 88a were used, which are described as deep infrared filters allow no visible light to pass through.The Wratten 87 filter has a sharp cut-off at 800nm, and so transmits freely throughout the infrared region.The 88A has a slightly narrower window with an effective cut-off at 750nm.The control photographs were taken using a UV/IR barrier filter.All photographs are taken at a 90 angle from the subject (as close to as possible without actually measuring the exact angle) this was to eliminate any false positives due to raised tattoos (which can chance in hot conditions).A colour scale, a grey scale and a sizing scale are held in place around the tattoo.The first photo taken is the control photograph, using the IR-UV cut lens. This allows visible light to be captured and so essentially, is just a normal (visible light) flash photography picture.The second photograph removes the UV-IR cut lens, replacing it with an IR filter. The first used is the Wratten 87, as many photographs as necessary are then taken using this filter. The terzetto set of photographs is taken with the 88a IR filter.The Metz 45CL4 electronic flash gun was the light meter of choice, the setting of which differs between photos depending on the light source available at the location.A number of photographs were taken of each tattoo one control photograph, and 2 photographs using each filter. The first infrared photograph was to capture the entire tattoo, including the scales. A second photograph was taken if deemed necessary, which was a close up shot, focussing on any areas of interest highlighted in the first infrared photograph in order to capture better detail.Once all of the photograph records were obtained they were categorized into successfu l and unsuccessful. Of the successful results, due to the varying degrees of success encountered from record to record, it was felt necessary to categorize further still with the introduction of a grading system.The grading system is as follows0 None of the original tattoo could be visualised1 Partial original tattoo visualisation2 Most of original tattoo can be seen3 All of the original tattoo can be seen from underneath the cover tattoo.Please note that some of the images presented in this report have only undergone basic alterations post production. The changes made to the infrared images were limited to minor brightness and contrast changes to accentuate any detail in the pictures that may have been lost when the images were resized and in order to defend detail in the printed hard copy. These changes are as followsBrightness was altered to a maximum of around -10% for the infrared images on Microsoft Office Word 2007. blood was altered to a maximum of +30% on Microsoft Off ice Word 2007.These values are approximate, and dependant on the detail captured in the original, unaltered photographs. The images were not altered in any other wayThe underlying tattoo can be somewhat visualised under visible light photography conditions however visualisation of the original tattoo is accentuated using the Infrared as it removes the camouflage or interference provided by empurpled shading of the cover tattoo. This is a grade 2 example.This was graded as 2 because a substantial amount of the original tattoo can be recovered. In this case, the tattoo, under visible light conditions, is not an obvious cover tattoo as no detail of the underlying tattoo can be detected due to the use of shading and the faded nature of the original tattoo. With the shading of the cover tattoo removed using the IR filters the detail in the original tattoo can be visualised. The black shading of the cover tattoo on the eagles head and wings is not visually removed by the infrared, and so part of the cover tattoo is still camouflaged.Note The dark green and blue of the original tattoo appear darker in the infrared than the other colours of the cover tattoo. The purple in the background has completely disappeared in the infrared photograph.This is a particularly interesting record as it demonstrates the absorbing capabilities of black ink. Although some of the original design can been seen in the control photograph it is somewhat polluted by the dark colours of the cover tattoo. The blue and particularly by the purple of the cover design are visually removed in the infrared photograph, highlighting the contrast and allowing for better determination of the actual design.It would be expected that if there were a trend amongst these results that as the time since the cover tattoo increases, so would either the success or failure rate. At the same time, the remaining (factor either success or failure) would decrease as the other increases to show that there is a clear correlation. This does not occur, and so suggests that there is no link between time since the cover tattoo, and the overall success rate.Also there does not appear to be any detectable trend in the observed graph patterns between fig. 9 and fig.10A summary table of records, including information on colours used, the grade allocated to each record, and a brief description of what can be seen with each record, is available in the appendices (Appendix 4) the findings of which are discussed in the discussion section of this research paperIt should be noted that this graph only presents the number of cover tattoos with black ink in the design and does not take into account whether or not the black ink is directly responsible for the obscuring of the original tattoo design. It does, however, present a slight trend, which is to be expected.In cases where the cover tattoo is colourful, the Wratten 87 filter appeared to be the filter of choice as it removed all colour of the cover design to reveal the underlying original tattoo.In cases where the cover tattoo consisted of cut black or grey shading, the Wratten 88a appeared to be the ideal filter to better accentuate the original design from the cover tattoo design traffic.Of the unsuccessful examplesThe following results are characterised according to the observed reason why the original tattoo could not be visualised. Please note that in 100% of the unsuccessful records the cover tattoo design contained black ink, however in some cases it is not deemed to be the reason for unsuccessful visualisation (In some cases for example, the black of the cover does not cover the original design)DiscussionThis research has proved definitively that infrared photography can be employed to detect an original tattoo design from underneath a cover tattoo.Of the several factors investigated in this paper that were thought to affect the success of the recovery of the original tattoo using the IR filters, the only factor with any real m erit were the colours used in the original and cover tattoos.The time since the cover tattoo was investigated due to the behaviour of the ink once deposited in the skin. As explained in the tattoo process section, once the ink is deposited, over time some of the particles will disperse throughout the dermis. It was thought that the effect of this, if any, would be to hinder any successful recovery of the underlying tattoo.No obvious correlation was discovered between the time since the cover tattoo and the successful recovery of the original tattoo from underneath the cover tattoo. cartridge holder between original tattoo and cover tattoo also yielded no apparent association to the success rate. The graphs and a brief description of the findings can be seen in the results section of this paper (fig. 18 and Fig. 19)When looking at the area on the body as a factor (essentially that is looking at the depth or thickness of the skin) it seemed necessary to take two examples from areas of differing skin thickness and compare the success rates from each.The skin thickness of the wrist will be significantly less than the thickness of the skin on the back, which along with the soles of the hands and feet, is one of the areas on the body of the largest skin density. Of the results for the wrist tattoo, 50% were successful. This was the same as with the results from the examples photographed on the back (Fig.17) suggests that the area on the body of the tattoo had little or no bearing on the results.As predicted it is the colours used in both the original underlying tattoo, and the cover tattoo, that has the most bearing on the successful visualisation of the original tattoo.Visualisation of the underlying tattoo was most prominent and effective with the examples with purple, red, light blue and white cover tattoos this is likely to be due to the different chromophores (the functional group of the pigment molecule that gives it its colour) in the different colours used , as they will absorb or reflect the infrared wavelengths at varying levels. Red and purple cover designs yielded the best results because these colours were completely visually removed by the infrared filters, leaving only the underlying original tattoo visible.Referring to Fig.1 and 2 of record 26, the purple of the cover design is completely visually removed under the infrared photographic conditions, allowing the black outline of the original underlying tattoo to be completely visualised.Records 22, 26 and 26b are by chance the best examples, each receiving grade 3 in the grading system for complete visualisation of the original tattoos. The original designs can be easily distinguished as there is no interference from any fragm