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Tattoos are a valuable agencies of designation in forensic and condemnable instances, nevertheless sometimes a instance presents itself where this peculiar method of designation is made purposefully complicated either by remotion or change, or where environmental factors have worked to perplex the designation of tattoo designs, for illustration tattoos found on mummified remains ( Zimmerman et al, 1975 ) .

McKechnie et Al ( 2008 ) and J & A ; ouml ; rg et Al ( 1938 ) have demonstrated that it is possible to visualize otherwise undetectable tattoos ( For illustration, tattoos treated by optical maser remotion ) , but what about when this separating characteristic of an person is for good covered, instead than removed, with another design or barricade coloring materials?

The usage of infrared picture taking in medical specialty to see the hypodermic web of venas illustrates its ability to perforate the superficial beds of the tegument, and to observe infrared absorbing constructions deeper in the tegument. This information, along with the findings of several surveies into the usage of infrared picture taking in scrutiny of questioned paperss, or more specifically suggested it would be possible to see the original implicit in tattoo from beneath a screen tattoo.

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The purpose of this survey was to try to visualize an original tattoo, or at least adequate to once and for all turn out its presence, from underneath a screen tattoo utilizing non invasive infrared digital picture taking. A sample size of 33 persons ( 37 records in entire ) volunteered to take part in the survey, their screen tattoos were photographed utilizing the IS Pro camera at a 90 & A ; deg ; angle from the country of involvement. The camera was set to ISO 200 f6.3 and infrared filters 87 and 88a were used.

This research indicated that the successful recovery of the original implicit in tattoo was chiefly dependant on the colorss used in the screen design


Thankss to Professor David Bryson for supplying the equipment and the information and experience needed to exert it and to my undertaking supervisor Jon Wright.

Thankss to Carrie Bowman and Chris Howell who travelled nigh and far with me and helped recruit and exposure participants.

Thankss to everyone who took clip out of their twenty-four hours to take part in this research


Tattoos have been an priceless method for the designation of non – skeletonised remains. The design and/or location of the tattoo can be well sole to supply equal designation, and particularly when combined with other separating characteristics they can definitively place and single.

During an necropsy the diagnostician will take note of tattoos merely as they would any other distinguishing Markss, such as birth Markss, defects or cicatrixs. In instances such as mass catastrophes, it can sometimes be one of merely few methods available for the initial scrutiny of the remains. In 2001, Kingsholm et al studied several unidentified organic structures and remains found in Danish Waterss, some of which had tattoos. Discovery and detailing of any tattoos can besides help in following unidentified organic structures back to their cultural backgrounds, therefore in some instances tattoos have of import historical facets.

Tattoo can besides bespeak a history of captivity ( Mallon et al 1999 ) and in such instances the single sporting this alone design may non wish to be easy identified. Repeat wrongdoers for illustration, may take to take or change their shaping characteristics and members of packs or organised offense groups may wish to no longer be associated with that peculiar cabal. Some tattoos may function to link one person with another, such as ‘love ‘ tattoos, which can besides help in designation of the single featuring the design.

Different visible radiation beginnings and filter techniques have been used routinely in condemnable probes ; the undermentioned utilizations of infrared ( IR ) picture taking presented in this debut are all relevant to this survey as they go some length towards explicating the nature of infrared and therefore what might be expected, leting for tax write-off of a hypothesis which is presented subsequently in this study.

Infrared describes the portion of the spectrum merely beyond the seeable ruddy wavelengths ( 700 – 1200 nanometer )

There are many used of infrared picture taking crossing many different Fieldss.

For art picture taking intents, Infrared can be used to snap objects in the distance, or in dazed conditions due to the infrareds ability to perforate the haze ( Milsom 2001 ) . For portrayal picture taking, infrared is sometimes favoured to give the visual aspect of a clear skin color

Medical utilizations of Infrared picture taking

Infrared ‘s ( IR ) ability to perforate the superficial beds of the cuticle of tegument is exploited in medical picture taking as a method of snaping venous forms underneath the tegument and of documenting mending under lesions in the tegument. They found that imaging in the near-infrared scope provided comparatively good contrast of hypodermic venas. This works due to the fact that hemoglobin is a chromophore that absorbs near infrared, and the tegument absorbs really small IR relation to the soaking up of infrared demonstrated by the venas ( Haxthausen, 1933 ) , or transmits or reflects most of the close infrared spectrum, therefore it appears lighter by contrast to the darkened venas.

Zharov et Al ( 2004 ) identified the potency of this technique as a diagnostic method for varicose venas at a deepness of 1-3mm into the tegument.

The usage of infrared picture taking for the sensing of varicose venas or any other hypodermic abnormalcies is demonstrated by Marshall ( 1981 ) . This research uses infrared coefficient of reflection ( every bit good as UV ) to mensurate the densenesss across pigmented lesions of the tegument and found it to be a utile method.

The survey by Haxthausen ( 1933 ) found that for documenting superficial afflictions, such as psoriasis, ordinary picture taking was far superior to infrared picture taking, as under the infrared conditions, the imperfectnesss were removed. Afflictions that occurred in the deeper beds of the tegument were captured best utilizing infrared picture taking.

In instances of burn hurt is can be hard to measure the harm or the thermic burn deepness. Anselmo et Al ( 1976 ) found that infrared picture taking could be used as a valuable and non invasive method of assess burn deepness. Their experiment used Wratten 89A infrared filter Infrared picture taking allowed for the distinction between feasible and necrotic corium.

Infrared picture taking of bloodstains and Gunshot residue

Forensic applications of infrared picture taking include observing gunshot residue on vesture ( Bailey et al 2007 ) and less normally, for observing bloodstains on dark vesture or at offense scenes. A study by Raymond and Hall in 1986 illustrated a dark colored couch, showcased in the study as a black and white exposure for the ocular spectrum comparing. In this exposure there is no obvious bloodstain, it can non be distinguished from the remainder of the couch due to the dark coloring material of the couch. The infrared exposure was taken utilizing the Wratten # 88a filter. In this exposure the couch had lightened and now by comparing, the country of bloodstained couch ( now darkened by contrast ) could easy be distinguished.

When utilizing infrared picture taking to observe and document hints of blood on dark vesture, the infrared will do the blood look darker and the environing vesture appear igniter by contrast. This is all due to the absorbing capablenesss of the vesture and of the blood. Blood absorbs throughout the seeable spectrum and the close infrared spectrum ( typically absorbing most wavelengths of close infrared 700-900nm ) and so its visual aspect in infrared records will be darkened, in contrast the vesture might merely absorb through the seeable light scope of the spectrum, and so in the infrared records will look lighter, or transparent.

Dark vesture can impede the successful visual image of blood splatter forms in much the same manner that darkened mummified tegument can impede the sensing of tattoos, or that coaling on a fire damaged papers can impact the successful visual image of the authorship. A survey by Perkins ( 2005 ) used digital infrared picture taking, Wratten # 89B filter to snap blood splatter on several different stuffs. The dark vesture appeared to reflect the infrared, therefore heightening the contrast between the vesture and the blood forms.

Bailey et Al ( 2007 ) used digital infrared picture taking to better visualise gunfire residue on dark vesture. It is really similar in both methodological analysis and consequences to the usage of this technique in bloodstain analysis. The camera ISO was set at 200 and the filter used was the Wratten # 87. The GSR, undetected under seeable light conditions, appeared dark against a lightened fabric under IR.

The usage of infrared in analysis of blotted out Hagiographas and questioned paperss

Infrared picture taking besides has many applications in the field of forensic scientific discipline.

It is a common method for observing obliterated authorship ( Creer 1976 ) for observing forged, or altered paperss, such as checks and to assistance in the scrutiny of composing obscured by coaling on fire damaged paperss ( Bartha. 1973 )

McCaul et Al ( 2007 ) discuss the jobs confronting forensic scientists when traditional picture taking techniques fall abruptly at documenting certain grounds. In the scrutiny of paperss, IR can be used to observe counterfeits or changes, trusting on the fact that the visually similar inks may reflect or absorb infrared at varying degrees and wavelengths.

Analogues can be drawn between the utilizations of infrared for analyzing obliterated authorship and this survey into analyzing original tattoos from underneath screen tattoos. The usage of rectification fluid or other inks to cover composing serves to render the underlying text illegible, in the same manner that the screen tattoo serves to falsify, conceal or wholly cover the original implicit in tattoo. If infrared picture taking can let for the underlying authorship to be visualised, than it is wholly possible that underlying original tattoo could be recovered. The successful recovery of blotted out Hagiographas is dependent on the different inks used and their infrared absorbing capablenesss. 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. Other illustrations include chlorophyll, melanin and amethyst.

Infrared picture taking can besides be used to examine/restore composing on charred paperss ( Bartha 1973 ) . The success of the visual image is dependent on the grade of charring. The charred paper is darkened due to partially converted pitchy stuff before being wholly degraded to simple C. The C 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 frequently used in the scrutiny of blotted out authorship ( G M Mokrzycki 1999 ) . The VSC uses Infrared radiant energy and filters to see through inks and other annihilations, and uncover obscured objects. The usage of infrared picture taking is non an uncommon method for visualizing and entering blotted out authorship, S. Sugawara ( 2004 ) discusses the usage of both close and in-between infrared in decoding obliterated Hagiographas by looking at composing made by 101 different pens.

Erasures describe inks that have been made unseeable by remotion of the color constituents of the inks. Sometimes when these constituents are removed, leftovers are left behind. Sometimes whatever remains on, or merely below, the surface can be detected utilizing infrared. This is the same rule encountered in a paper by McKechnie et Al ( 2008 ) in which infrared was used to observe leftovers of ink left behind in the skin post-laser remotion intervention. The findings of this research will be analysed in greater item later on in this research paper.

Other utilizations of infrared picture taking

The utilizations of Infrared picture taking do non get down and stop at medical and forensic utilizations nevertheless, for illustration, Bridgeman and Gibson ( 1963 ) used infrared to analyze pictures.

A paper by J R J Van Aperen De Boer ( 1969 ) successfully applies Infrared Reflectography to see the under-drawings of C pencil, with changing grades of success of mediaeval pictures.

Pencil lead ( which is chiefly graphite ) absorbs throughout the infrared scope of the spectrum, and the seeable scope. Because of this, under both close and far infrared conditions the black lead will stay as readily viewable as to the bare oculus.

Therefore far this undertaking has looked at both medical and forensic utilizations of infrared picture taking, many of which have in common the thought that infrared can be used to retrieve, or detect hints of one stuff ( for illustration ; ink ) from underneath another stuff ( such as rectification fluid ) . These underlying or otherwise ‘camouflaged ‘ stuffs are non readily viewable with the bare oculus, or easy recorded utilizing ordinary photographic methods. This is the same rule as is to be employed in this research.

The sensing of latent residue tattoo ink pigments

The usage of infrared picture taking to enter tattoos is by no agencies a recent phenomenon. As long ago as 1938 J & A ; ouml ; roentgeniums used infrared picture taking to observe tattoos that were otherwise undetectable with the bare oculus.

Although infrared picture taking has been utilized to analyze tattoos, there is non a great trade of literature available on the subject. Below some specific illustrations are given. The following are 2 illustrations found provide utile proof of infrared penetrating capablenesss coupled with its specific usage for observing tattoo designs that have been affected by environmental conditions, or purposefully made hard to visualize:

Mckechnie et Al usage infrared picture taking to try to visualize latent tattoo ink residue from optical maser removed tattoos.

This research article merely used 2 participants, and with a success rate of 50 % and so a follow up experiment would be required utilizing a larger sample size to formalize the findings. Both participants had their tattoos removed by optical maser intervention to the extent that they were no longer seeable to the bare human oculus. One of the participants ‘ tattoos was professionally done ; the other was an recreational tattoo. Although the writers explain the difference between amateur and professional tattoos as a possible factor ( that is that professional tattoos usage more ink and are injected deeper into the corium than recreational tattoos ) and cross mention it with infrared ‘s ability to perforate the tegument, they do non spread out on the coloring material or pigment as being factors ensuing in the success or failure of the test.

Visualizing tattoos on mummified remains utilizing infrared picture taking

One of the original diary articles of involvement that could be said to hold initiated the idea behind this undertaking thought, or at the really least animate a belief of the success of the undertaking, uses infrared Reflectography to analyze tattoos on mummified remains, the mummified tissue usually being darkened to the extent that visual image under normal picture taking conditions is near impossible ( Alvrus et al 2001 ) It showcases the utility of infrared for buoy uping certain facets of a topic in order to see others. In this instance, the darkened mummified tissue made it hard to visualize the tattoo under normal photographic conditions ( seeable visible radiation ) . Under Infrared conditions nevertheless, the contrast between the tattoo and the environing tegument was enhanced ; the darkened mummified tegument appeared lighter, and by contrast the tattoo ( which appeared darker ) was readily seeable. This is due to the differing absorption/reflection of infrared. The substances in the tattoo absorb the bulk of the infrared ; the environing tegument reflects the infrared.

A similar technique is used in the designation of tattooing on a 1600 twelvemonth old mummified organic structure found in Alaska ( Smith and Zimmerman 1975 ) Tattooing was identified on the custodies and forearms of the Eskimo female remains utilizing infrared picture taking. The darkened tegument obscured the tattoos to the extent that they could non be viewed under seeable light spectral scope picture taking.

Skin thickness as a factor

One of the other variables accounted for in this undertaking is the country on the organic structure of that tattoo, the idea behind this being that the thickness of the tegument might come into drama. Harmonizing to E J Wood ( 1985 ) the thickness of the epidermis scopes from 0.06 – 0.1mm ( from palpebras, to endorse and callused countries, severally ) . The dermis scopes from 2 – 4mm midst, and histories for the majority of the tegument. Although any differences in skin deepness tend to be minute, they may still account for variable success rates due to the migrating nature of tattoo ink through the corium and the perforating capablenesss of infrared. A skilled tattooist will non let the acerate leaf to perforate the tegument no deeper than 2mm, the grounds for which are discussed below in ‘The tattoo procedure ‘ . The ink must be deposited deeper than the cuticle, or else the ink will melt as the outer beds of the tegument shed, therefore the thickness of the cuticle will impact how deep the ink must be deposited. It is besides assumed that the thickness of the corium will correlate with the thickness of the cuticle. This is why this research paper has chosen to look at the country on the organic structure of the tattoo as a possible factor.

The tattoo procedure

The procedure of tattooing involves shooting pigment, suspended in a bearer, through the cuticle and into the corium of the tegument, no more than 2mm or else the tattooist hazard the ink hemorrhage, making a smudged consequence, irrespective of the tattoo technique employed ( the scenes of the modern tattoo machine do non let for the acerate leaf to perforate any deeper than 2mm ) . There is no exact scientific discipline as to the force per unit area exerted on the acerate leaf by the single tattooist, as it is a affair of personal opinion ( direct citation from Mark – tattooist from Danny ‘s tattoo Studio in Sneinton, Nottingham ) depending on the country of the organic structure on which the tattoo is being performed. Tattooing on an person ‘s dorsum or upper arm will necessitate greater force per unit area because the tegument is much thicker, the scene of the tattoo machine will besides hold to be altered for deeper incursion through the cuticle and into the corium.

Once injected into the upper bed of the corium, the pigment is suspended in the fibroblasts ( Sperry 1991 ) . When looking at a tattoo, the tattoo is being viewed through the cuticle.

Over clip the deposited tattoo ink will scatter deeper into the corium, and so it is possible that clip, both between original and screen, and clip since screen, could be a characteristic in the probe.

Tattoo Ink pigments

More frequently than non, the tattooist will utilize a tattoo ink incorporating pigments which will be manufactured outside of the tattooist ‘s ain premises, the exact content and pureness of which is in most instances, unknown. There are certain guidelines in topographic point for makers of tattoo inks to stay by when bring forthing the inks, nevertheless makers of tattoo ink are non forced by jurisprudence to unwrap the ingredients used in the inks. A survey by Timko et Al ( 2001 ) found that, of 30 inks studied, the most normally identified elements were aluminium, O, Ti and C at 87, 73, and 67 per centum severally.

Professional tattoo creative persons have entree to over 100 different colorss ( Kirby et al 2005 ) , many of these are mixtures of colorss, for illustration ruddy and white to do pink, therefore doing it hard to sort pigment-wise. The research by Kirby et Al ( 2005 ) found important variableness in pigment bunch sizes in professional tattoos, compared to amateur tattoos. They besides found color pigment granules to be larger than black pigment granules.

This was ab initio an country of involvement, but non one that this research paper will concentrate on due to the trouble encountered in obtaining the relevant information.

This survey uses infrared picture taking in an effort to visualize an original tattoo from underneath a screen tattoo, the success of which could be due to a figure of different factors. A sum-up of these factors are as follows:

  • To look at the colorss used in both the original tattoo and the screen tattoo and how this affects the successful visual image of the original tattoo utilizing infrared.
  • To look for any correlativity associating clip since screen tattoo ( up to day of the month of exposure ) and success of the experiment. This basically will be looking at the effects of the migration of tattoo ink.
  • To look at any tendencies affecting clip elapsed between original tattoo and screen tattoo, and the success of the infrared exposure obtained. As above, this will be analyzing the effects of ink atom migration.
  • To look at the country on the organic structure of the tattoo and discover if there is a relationship between this and the success of a peculiar exposure. Basically, this is probe skin denseness as a factor.

Taking into history all the research discussed antecedently and the consequences obtained by the assorted surveies in the field of infrared picture taking a few hypotheses have been deduced:

The first is that the acute nature of infrared suggests it is possible to retrieve the implicit in pigment of the original tattoo from beneath the screen tattoo. The grounds behind this are thought at this phase to be due to the colors present, or possibly even the concentration of black used in the coloring material mixtures.

The manner in which an object appears when photographed utilizing infrared is a direct effect of their absorbing capablenesss.

For the intents of this peculiar survey inspiration was drawn for the research into questioned paperss, or more specifically the sensing of different inks utilizing infrared. Most inks have different absorbing capablenesss, some will merely absorb through the seeable light spectrum, and some throughout the seeable visible radiation and into the infrared scope. The ground behind this, as mentioned earlier, is due to the chromophores in the dye molecules.

In the same manner that infrared might be used to observe the underwritings of blotted out text, IR could be used to observe the underlying tattoo pigment, depending on the chromophores, or colorss used.

The 2nd hypothesis is that any fluctuation in the depth/thickness of the tegument will be such a minute difference that it is improbable to impact the overall success of the undertaking.

The factors of clip ( clip between original and screen, and clip since screen ) are likely to hold minimum consequence, if any, on the successful ocular recovery of the underlying tattoo. It is thought that any tendencies are more likely to be observed in the utmost clip periods, for illustration, between tattoos that are under a twelvemonth old and tattoos that are over 30 old ages old. This is because the most late done tattoos will non hold been affected by migration, whereas really elderly tattoos will hold undergone decennaries of migration of the ink atoms.

Method and stuffs

A sample figure of 33 ( n33 ) persons were used in this research, all of whom volunteered their clip and consented for the presentation of their tattoos anonymously in this research paper. All that was required of possible participants was that they had a screen tattoo, there was no other standards selected for, for illustration age or gender. The participants were so required to make full out a consent signifier, as no exposure could be taken without. The participants were asked to make full out a short questionnaire to assistance in probe of the assorted factors discussed in the debut, an illustration of which can be found in the appendix.

This undertaking utilizes the close infrared portion of the spectrum ( the far infrared portion of the spectrum is normally used for thermic imagination ) . The infrared filters allow infrared visible radiation to go through through the camera and blocks most of the seeable light spectrum.

The Fujifilm IS pro digital SLR camera is sensitive to both UV and infrared visible radiation between 380nm and 1000nm.

Optimum scenes for the camera were assessed during several pre-experiments. Manual scene, ISO 200 and aperture f/6.3, which provided equal deepness of field for the infrared exposure

Filters 87 and 88a were used, which are described as deep infrared filters ; let no seeable visible radiation to go through through.

The Wratten 87 filter has a crisp cut-off at ~800nm, and so transmits freely throughout the infrared part.

The 88A has a somewhat narrower window with an effectual cut-off at ~750nm.

The control exposure were taken utilizing a UV/IR barrier filter.

All exposure are taken at a 90 & A ; deg ; angle from the topic ( as near to as possible without really mensurating the exact angle ) this was to extinguish any false positives due to raised tattoos ( which can go on in hot conditions ) .

A color graduated table, a gray graduated table and a sizing graduated table are held in topographic point around the tattoo.

The first exposure taken is the control exposure, utilizing the IR-UV cut lens. This allows seeable visible radiation to be captured and so basically, is merely a normal ( seeable visible radiation ) flash picture taking image.

The 2nd exposure removes the UV-IR cut lens, replacing it with an IR filter. The first used is the Wratten 87, as many exposure as necessary are so taken utilizing this filter. The 3rd set of exposure is taken with the 88a IR filter.

The Metz 45CL4 electronic flash gun was the light metre of pick, the scene of which differs between exposures depending on the light beginning available at the location.

A figure of exposures were taken of each tattoo ; one control exposure, and 2 exposures utilizing each filter. The first infrared exposure was to capture the full tattoo, including the graduated tables. A 2nd exposure was taken if deemed necessary, which was a close up shooting, concentrating on any countries of involvement highlighted in the first infrared exposure in order to capture better item.

Once all of the exposure records were obtained they were categorized into ‘successful ‘ and ‘unsuccessful ‘ . Of the successful consequences, due to the changing grades of success encountered from record to record, it was felt necessary to categorise further still with the debut of a scaling system.

The scaling system is as follows:

  • 0 – None of the original tattoo could be visualised
  • 1 – Partial original tattoo visual image
  • 2 – Most of original tattoo can be seen
  • 3 – All of the original tattoo can be seen from underneath the screen tattoo.

Please note that some of the images presented in this study have merely undergone basic changes station production. The alterations made to the infrared images were limited to minor brightness and contrast alterations to stress any item in the images that may hold been lost when the images were resized and in order to retain item in the printed difficult transcript. These alterations are as follows:

Brightness was altered to a upper limit of around -10 % for the infrared images on Microsoft Office Word 2007.

Contrast was altered to a upper limit of +30 % on Microsoft Office Word 2007.

These values are approximative, and dependent on the item captured in the original, unchanged exposure. The images were non altered in any other manner

The underlying tattoo can be slightly envisioned under seeable light picture taking conditions nevertheless visual image of the original tattoo is accentuated utilizing the Infrared as it removes the disguise or intervention provided by violet shading of the screen tattoo. This is a grade 2 illustration.

This was graded as 2 because a significant sum of the original tattoo can be recovered. In this instance, the tattoo, under seeable light conditions, is non an obvious screen tattoo as no item of the underlying tattoo can be detected due to the usage of shading and the bleached nature of the original tattoo. With the shading of the screen tattoo removed utilizing the IR filters the item in the original tattoo can be visualised. The black shading of the screen tattoo on the bird of Jove ‘s caput and wings is non visually removed by the infrared, and so portion of the screen tattoo is still camouflaged.

Note – The dark green and blue of the original tattoo appear darker in the infrared than the other colors of the screen tattoo. The purple in the background has wholly disappeared in the infrared exposure.

This is a peculiarly interesting record as it demonstrates the absorbing capablenesss of black ink. Although some of the original design can been seen in the control exposure it is slightly polluted by the dark colors of the screen tattoo. The bluish and peculiarly by the purple of the screen design are visually removed in the infrared exposure, foregrounding the contrast and leting for better finding of the existent design.

It would be expected that if there were a tendency amongst these consequences that as the clip since the screen tattoo additions, so would either the success or failure rate. At the same clip, the staying ( factor – either success or failure ) would diminish as the other additions to demo that there is a clear correlativity. This does non happen, and so suggests that there is no nexus between clip since the screen tattoo, and the overall success rate.

Besides at that place does non look to be any noticeable tendency in the ascertained graph forms between fig. 9 and fig.10

A drumhead tabular array of records, including information on colors used, the class 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 treatment subdivision of this research paper

It should be noted that this graph merely presents the figure of screen tattoos with black ink in the design and does non take into history whether or non the black ink is straight responsible for the obscuring of the original tattoo design. It does, nevertheless, present a little tendency, which is to be expected.

In instances where the screen tattoo is colorful, the Wratten 87 filter appeared to be the filter of pick as it removed all coloring material of the screen design to uncover the implicit in original tattoo.

In instances where the screen tattoo consisted of cut black or gray shading, the Wratten 88a appeared to be the ideal filter to better stress the original design from the screen tattoo design traffic.

Of the unsuccessful illustrations:

The undermentioned consequences are characterised harmonizing to the ascertained ground why the original tattoo could non be visualised. Please note that in 100 % of the unsuccessful records the screen tattoo design contained black ink, nevertheless in some instances it is non deemed to be the ground for unsuccessful visual image ( In some instances for illustration, the black of the screen does non cover the original design )


This research has proved definitively that infrared picture taking can be employed to observe an original tattoo design from underneath a screen tattoo.

Of the several factors investigated in this paper that were thought to impact the success of the recovery of the original tattoo utilizing the IR filters, the lone factor with any existent virtue were the colorss used in the original and cover tattoos.

The clip since the screen tattoo was investigated due to the behavior of the ink one time deposited in the tegument. As explained in the tattoo procedure subdivision, one time the ink is deposited, over clip some of the atoms will scatter throughout the corium. It was thought that the consequence of this, if any, would be to impede any successful recovery of the underlying tattoo.

No obvious correlativity was discovered between the clip since the screen tattoo and the successful recovery of the original tattoo from underneath the screen tattoo.

Time between original tattoo and screen tattoo besides yielded no evident association to the success rate. The graphs and a brief description of the findings can be seen in the consequences subdivision of this paper ( fig. 18 and Fig. 19 )

When looking at the country on the organic structure as a factor ( basically that is looking at the deepness or thickness of the tegument ) it seemed necessary to take two illustrations from countries of differing skin thickness and compare the success rates from each.

The skin thickness of the carpus will be significantly less than the thickness of the tegument on the dorsum, which along with the colloidal suspensions of the custodies and pess, is one of the countries on the organic structure of the largest skin denseness. Of the consequences for the carpus tattoo, 50 % were successful. This was the same as with the consequences from the illustrations photographed on the dorsum ( Fig.17 ) suggests that the country on the organic structure of the tattoo had small or no bearing on the consequences.

As predicted it is the colorss used in both the original underlying tattoo, and the screen tattoo, that has the most bearing on the successful visual image of the original tattoo.

Visual image of the underlying tattoo was most dramatic and effectual with the illustrations with purple, ruddy, light blue and white screen tattoos – this is likely to be due to the different chromophores ( the functional group of the pigment molecule that gives it its coloring material ) in the different colorss used, as they will absorb or reflect the infrared wavelengths at varying degrees. Red and purple screen designs yielded the best consequences because these colorss were wholly visually removed by the infrared filters, go forthing merely the implicit in original tattoo seeable.

Mentioning to Fig.1 and 2 of record 26, the purple of the screen design is wholly visually removed under the infrared photographic conditions, leting the black lineation of the original implicit in tattoo to be wholly visualised.

Records 22, 26 and 26b are possibly the best illustrations, each having class 3 in the scaling system for complete visual image of the original tattoos. The original designs can be easy distinguished as there is no intervention from any fragments of the screen tattoo left behind under the infrared conditions.

Record 22 ( Fig.12 and 13 ) is an illustration of a darker original tattoo design with a black lineation covered with ruddy and violet ink design. The original tattoo design in record 22 could be merely slightly detected utilizing seeable light picture taking and electronic flash, nevertheless the item of the designs could non be visualised due to consider shading of the screen tattoo. Under IR photographic conditions, the red of the screen tattoo appeared transparent, and the implicit in design could now be viewed with no intervention of the screen tattoo.

In Record 4b, the original design was significantly bleached black authorship. Mentioning back to the work of McKechnie et Al ( 2008 ) it is already established that infrared will observe and stress faded or purposefully removed tattoo residue in the tegument.

Record 4b besides illustrates this, as the item hardly noticeable by the bare oculus becomes significantly more legible utilizing infrared filters.

Of the 20 successful consequences, 100 % of the records had black ink in the implicit in original tattoos, be it barricade coloring material, shadowing or merely lineation. In such instances as records 26 and 22 it was the black lineation of the original implicit in design that was most dramatic in the infrared image. As mentioned antecedently, this is because the black ink absorbs throughout the close infrared scope of the spectrum, and so any infrared that penetrated the tegument and was non absorbed by the assorted ink pigments used in the screen tattoo, would be absorbed by the black, and this would give a really strong successful visual image. Black ink used in the screen tattoo would forestall the infrared from observing anything beneath it ( fig. 25 )

Of the consequences graded 2 on the success graduated table, about 72.7 % had black in the screen tattoo. In those tattoos in which all of the original tattoo could be visualised, 0 % had black in the screen tattoo. Of the consequences graded 1 on the success graduated table, 100 % of the screen tattoos designs had an component of black ink, be it barricade coloring material, shadowing or merely outline. Of the unsuccessful records ( graded 0 ) , the bulk ( about 66.6 % ) were black screen tattoos, although 100 % of the consequences had black elements in the screen tattoo nevertheless, in instances such as where the original tattoo is integrated into the screen tattoo, it is thought that the presence of black is non the primary ground for the unsuccessful visual image of the original tattoo. Please refer to the appendix 5 ( the complete record aggregation )

Of the successful consequences, the variable degrees of success were more frequently than non attributed to presence of black in the screen tattoo, which unlike purple or ruddy, remained strong in the infrared exposure.

Grade 2 records, in the bulk of instances, stopped short of complete visual image ( grade 3 ) due to the presence of black ink in the screen design that still obscured portion of the original design. This is because the black pigment absorbs the infrared, and works in much the same manner as utilizing infrared to decode blotted out Hagiographas. The infrared penetrates the rectification fluid and is absorbed by the implicit in black ink ( Ellen, 2006 ) .

Second in the running for grounds as to why the experiments in these instances were unsuccessful was that the original tattoo design was integrated into that of the screen tattoo, which meant that regardless of any success in remotion of coloring material under IR conditions, the design of the original tattoo could non be readily distinguished from that of the screen design. This accounts for 4 out of the 18 unsuccessful consequences. For the staying 2 illustrations in the ‘other ‘ class, the grounds for the deficiency of success was attributed to the usage of similar ink colors in both the original and the screen tattoo designs and so it was hard to distinguish between elements of the two.

The other of the illustrations had had the original tattoo treated with 2 optical maser remotion interventions prior to the screen tattoo.

The Grey used in the screen tattoos is either a black and white mix or a cut black ( diluted with distilled H2O ) therefore thining the sum of black pigment, which could supply a principle as to why in some instances, under IR conditions, the Grey screen lightens leting the original tattoo, supplying the ink of which is darker, to be visualised more readily.

In some instances, peculiarly where the original tattoo used dark or black ink covered by a lighter tattoo or shading, the brassy conditions entirely were sufficient to observe all or portion of the original design.

There were a figure of cases where it was hard to categorise the findings:

Photograph 4b was a peculiarly interesting illustration of this. The screen tattoo did non try to camouflage the full original tattoo, it was non necessary as the original tattoo was sufficiently faded so as to do it hard, although non impossible, to observe with the bare human oculus. Although the original tattoo could non be visualised from underneath the black screen design, it did function to better visualize the original tattoo from in between the screen design.

Trouble was encountered when trying to categorise the consequences in the scaling system.

Record 16 was an interesting instance in point for the complexness of categorising the consequences. In this peculiar record, utilizing infrared picture taking a rectangular form, or form was detected that was non seeable in the control record, nevertheless, the original implicit in tattoo design was that of a love bosom, and so it was assumed that the rectangular form was a portion of the screen design and as no love bosom design could be detected, the record was graded 0.

Record 29 was another confusing illustration, as the screen tattoo was uncomplete, intending that the original tattoo could be slightly viewed under seeable light conditions. The screen tattoo was a series of lineations with small shading, all in black ink. This meant that the original design was seeable in both the control and infrared exposure, and so trouble was encountered in categorizing this peculiar record.

A Cadmium of the person records is included in this research paper ( appendix 5 )


There are a figure of grounds why an person might desire to cover a tattoo, such as a desire to maintain a concealed yesteryear, to mask association with a peculiar pack or civilization, to symbolically take a past loved 1s grade, or possibly more by and large merely to mask any distinguishing characteristic that might do them readily identifiable.

This research has proved that in certain state of affairss it can be possible to observe and visually retrieve an original tattoo design one time the tattoo has been for good covered, utilizing infrared picture taking.

Out of all the variables investigated in this paper, the lone 1 with any virtue appeared to be the colorss used in both the original and cover tattoo.

Successful visual image was dependent on the chromophores in the ink, which are responsible for the pigment molecule ‘s coloring material. These reflect and absorb infrared at varying degrees.

Black ink is good documented to absorb infrared, and this is validated by the findings of this undertaking. In all of the records, control and infrared likewise, the black remained the most outstanding component in footings of coloring material.

The colors most readily visually removed in all of the infrared records were violet and ruddy, as they transmit throughout the seeable scope of the spectrum, but reflect all infrared radiation and so although to the bare human oculus the violet appears as solid block coloring material, and the design can non be seen underneath ( records 26 and 26b ) nevertheless, under infrared conditions the colorss appear transparent, uncovering the concealed design.

Greenss and blues, although removed by the Wratten # 87 filter, were still present in the infrared records taken utilizing the Wratten # 88a filter.

This research validates the hypothesis that infrared picture taking can be used to visually retrieve underlying tattoos from screen tattoo designs done purposefully to blockade the visual image of said implicit in tattoo. The success of this engineering is dependent on the colorss used, viz. if the tattoo is covered with black ink the infrared will non observe anything beneath it. This is an priceless technique that could be used to place persons with a history of captivity or pack association that may hold had their identifiable symbol intentionally covered.

Future chances

  • Further survey could be done to measure the composing of inks. This was a hard undertaking as makers are non forced to unwrap the ingredients of the inks.
  • Other future chances include the possibility of looking specifically at optical maser treated original tattoos underneath screen tattoos utilizing infrared picture taking.
  • There are chances to farther pull strings the images on Photoshop package. These include nailing countries of utmost coloring material alterations, that is the countries of the records where the infrared visually removes the coloring material, and happening the differences in the RGB values to supply more informations for statistical analysis.


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