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Science & Justice

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Technical note

Fingermarks development on gloves: Relative efficiency of 1,2 Indanedione/ZnCl2, ninhydrin and wet powder

Mélina Rousseaua,b, Pierre Ledroita,⁎, Marianne Maloa, Damien Henrota, Hélène Guillea

a Forensic Science Laboratory of the French Gendarmerie, 5 boulevard de l’Hautil, BP 60036 ERAGNY, 95001 CERGY PONTOISE cedex, FrancebUniversity of Maine Institute of Technology, Chemistry Department, Avenue Olivier Messiaen, 72085 LE MANS cedex 9, France

A R T I C L E I N F O

Keywords:GloveNinhydrinIndanedioneWet powderPapillary mark

A B S T R A C T

Powder suspensions such as wet powder are used to develop fingermarks on adhesive surfaces. They can also beused on gloves but these ready-to-use commercial pre-mixed solutions are not entirely satisfactory. Among otherthings, they generate some background noise that can sometimes be substantial and make the exploitation of thefingermarks difficult. Recent studies have proven the effectiveness of a HFE ninhydrin solution on some types ofgloves. Ninhydrin and 1,2-indanedione are reagents that are commonly used for the visualisation of fingermarkson porous and semi-porous substrates. Applying them on gloves might help to overcome the issue of backgroundnoise being produced by powder suspensions. In this study, several formulations of ninhydrin and 1,2-in-danedione are compared to wet powder on a sample of nitrile, latex and vinyl gloves. The subsequent resultsshow a greater effectiveness with the use of wet powder.

1. Introduction

Gloves are frequently collected items on crime scenes. Perpetratorswear them to avoid leaving their DNA or fingermarks on site. Whenfound, these gloves can prove to be a mine of information about thegenetic profile of the the person who wore them as well as his finger-marks. However, this common item is still difficult to process as tra-ditional methods of fingermark visualisation often have inconclusiveresults. The evolution of manufacturing processes (including anti-al-lergenic treatments) and the different materials on the market (latex,vinyl, nitrile…) make the work of the experts much more complicated.It is often difficult to determine, in a simple and practical way, thenature of the glove before it is processed. The different chemical re-agents used during processing can have very different interactions de-pending on the material of the glove. Therefore, it seems appropriate tostudy this complex substrate and to determine if some techniques re-main efficient on a majority of gloves.

Various approaches have already been tried to visualise fingermarkson gloves. According to Pleckaitis, powder suspensions have quite sig-nificant results on nitrile gloves [1,2] but do not work on all types oflatex gloves. In his study, he achieves a high 77% rate of ridge detailsvisualization. The authors also note that the effects of donor and se-cretion type have on the efficiency of this method seem more importantthan the type of glove. Other studies have proven the ability of

ninhydrin to develop marks on latex gloves [1,3,4]. The first solutionswere heptane-based but the evolution in manufacturing processes, in aneffort to avoid any allergenic effect on the skin, has led to a change inthe chemical components of gloves. The surface of these gloves is nowaltered when in contact with some solvents. Other less damaging so-lutions with a methoxyperfluorobutane (or HFE 7100) have then beentried on latex gloves, with success [5]. Velders has also managed todevelop marks on latex and vinyl gloves without using any chemicalprocessing but by simply using gelatin lifters [6]. Other techniques,such as cyanoacrylate or ruthenium tetroxide fuming, have alreadyprovided positive results on these substrates [7,8].

There is no denying that we do not currently have a really efficienttechnique to visualize fingermarks on gloves. Most of laboratories usecurrently cyanoacrylate or wet suspension powder to develop finger-marks on gloves. Arbeli’s recent works [5] show the benefits of con-sidering gloves as semi-porous substrates and to treat them with aspecific ninhydrin solution. We may also consider that other amino acidreagents such as 1,2-indanedione could be effective [9,10].

The first difficulty with gloves is to have conditions where finger-marks could have been left by the bearer. To this end, it is necessary towear gloves of appropriate size thus providing a direct contact betweenskin and glove but they must also be worn for sufficient time. Thesecond difficulty arises from the extreme variability of gloves availableon the market. Several materials are available (latex, nitrile, vinyl…)

https://doi.org/10.1016/j.scijus.2020.07.002Received 25 March 2020; Received in revised form 2 July 2020; Accepted 4 July 2020

⁎ Corresponding author.E-mail address: [email protected] (P. Ledroit).

Science & Justice 60 (2020) 473–479

1355-0306/ © 2020 The Chartered Society of Forensic Sciences. Published by Elsevier B.V. All rights reserved.

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with specific treatments (powdered or powder-free, sterile or non-sterile) as well as different physical characteristics (thickness, surfaceroughness…) giving surfaces more or less favourable to fingermarks.Most of the time, determining the type and composition of a glovefound at a crime scene before looking for fingermarks is quite a chal-lenge for the experts. It is therefore essential to find a visualisationprocess that will be efficient on a large panel of gloves. And thus, theaim of this study is to compare the effectiveness of different visualisa-tion methods (ninhydrin, 1,2-Indanedione/ZnCl2 and Wet Powder) on awide variety of gloves.

Operational laboratories face a challenging surface with gloves.Some of these experts use powder suspensions, cyanoacrylate process orspecific ninhydrin formulation to develop fingermarks. But in manycases, a swab for DNA purpose is done instead of developing finger-marks due to the lack of an effective method.

2. Material and method

2.1. Gloves

So as to get a representative sample of what can be found at a crimescene, 16 types of gloves were used, including nitrile (10), latex (5) andvinyl (1) gloves. They are representative of the consumer market inFrance. Each type of gloves’ characteristics are detailed in Table 1.

2.2. Chemicals

1,2-Indanedione and ninhydrin powders and black and white wetpowders were purchased from BVDA. Ethanol (absolute), methanol,acetic acid (96%) and ethyl acetate were provided by VWR. HFE 7100was purchased from 3M.

2.3. Fingermark enhancement techniques

2.3.1. Ninhydrin and 1,2-Indanedione/ZnCl2The ninhydrin and 1,2-Indanedione/ZnCl2 formulations are detailed

in Table 2. For each reagent, two solutions were tested. The first one(IND-Zn 1 or Ninhydrine 1) corresponds to our current routine reagentin which HFE 7100 replaces petroleum spirit (to avoid glove dete-rioration). The second one (IND-Zn 2 or Ninhydrine 2) was a for-mulation already published [5].

The preparation of the Ninhydrin 2 solution requires the use of a

stock solution (Ninhydrin 2 stock) containing 5 g of ninhydrin powderdissolved in 5 mL of acetic acid, 45 mL of ethanol and 2 mL of ethylacetate. Then, 13 mL of this solution are then added just before pro-cessing to 250 mL of HFE 7100 to get the working solution.

The preparation of the IND-Zn 2 solution requires the use of a stocksolution (IND-Zn 2 stock) containing 0.125 g of 1,2-Indanedione dis-solved in 5 mL of acetic acid, 50 mL of methanol, 50 mL of ethyl acetateand 400 mL of HFE-7100.

The preparation of IND-Zn 1 and IND-Zn 2 requires the preparationof a zinc chloride solution beforehand. The solution containing 0.2 g ofzinc chloride is dissolved in 5 mL of ethanol, 0.5 mL of acetic acid and95 mL of HFE-7100.

The ninhydrin 1 solution precipitated after 24 h, therefore has notbeen retained for the study due to its instability.

The gloves were briefly immersed in the ninhydrin or 1,2-Indanedione/ZnCl2 solution and then allowed to air dry. After a fewminutes, treated substrates were protected from light, put in a reseal-able plastic bag and stored at room temperature in a ventilated closetfor 48 h. A climatic chambers where humidity rate and temperature arecontrolled could have been used to accelerate the reaction especiallywith ninhydrin, but this was not the case in this study. Enhanced fin-germarks, developed with ninhydrin in dark purple, were observed withwhite light. Enhanced fingermarks, developed with 1,2-Indanedione/ZnCl2, were observed using a Coherent Tracer laser at 532 nm to ir-radiate the samples with a green light and using an orange filter for thedigital recording.

2.4. Powder suspensions

The glove was first placed on a tilted working surface [11]. Blackand white wet powders are ready-to-use commercial powders fromBVDA. Before using them, they are shaken to get an homogeneousmixture. The white or black wet powder solution was then applied onthe glove using a brush so as to cover the whole surface. Once the wetpowder had been applied, the glove was immediately rinsed with water.It then air dried for 48 h before being analyzed. Enhanced fingermarks,developed with wet powder (white or black suspension), were observedwith white light.

2.5. Experimental conditions

The number of donors was fixed at 5 (4 males (35, 39, 44 and45 years old) and 1 female (23 years old)) thus bringing the number ofmarks to 30 allowing the comparative study (five fingerprints and onepalm print per donor). The donors rubbed their hands before putting onthe gloves so as to homogenise the secretions and the potential con-taminants on their hands. Gloves were then worn for 15 min. The glovesize was selected so as to provide a good contact between the skin andthe surface of the glove. Each glove was then removed, flipped andstored in a brown envelope (no light exposure) at room temperature.Between each sampling, a minimum time of 30 min is requested.

The effectiveness of the ninhydrin or 1,2-Indanedione/ZnCl2 solu-tions was evaluated in comparison to wet powder. The experimentalprotocol was defined in accordance to current recommendations [12].

Each type of glove was thus worn three times per donor.For the first wearing, the first glove was treated with the ninhydrin

2 solution, and the second glove with wet powder.For the second wearing, the first glove was treated with the IND-Zn1

solution, and the second glove with wet powder.For the third wearing, the first glove was treated with the IND- Zn 2

solution, and the second glove with wet powder.Different mark ageing were also tested during this study: 1 day,

7 days and 1 month.

Table 1List of gloves.

N° Brand Material Withpowder

Color Features

1 Nitra-Tex Micro-Touch Nitrile No Blue2 VWR Nitrile No Blue Light, harsh

surface3 LLG Labware Nitrile No Blue4 Kimberly-Clark Nitrile No Blue5 NightHawk Nitrile No Black Harsh surface6 Dexter Nitrile No Blue Harsh surface7 Kimtech (Science

Brand), nitrile-xtraNitrile No Blue or

violetHarsh surface

8 Semper quard Nitrile No Blue Harsh surface9 Kimtech (Pur Brand) Nitrile No White Sterile10 VWR Nitrile No Blue11 Mapa professionnel,

solo extra 998Latex No Yellow

12 Mapa confort pro Latex Yes White13 VWR international Latex Yes White14 Triflex Latex Yes White Sterile15 Medical polysem Latex No White16 Vinyl Vinyl No White

Harsh surface:internal surface of the glove is a bit rough, not smooth.

M. Rousseau, et al. Science & Justice 60 (2020) 473–479

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2.6. Instrumental

All enhanced fingerprints were digitally recorded using a NikonD800 with a 105 mm camera lens. The lighting conditions (white lightor green light) as well as the use of a specific bandpass filter dependedon the method used to develop latent fingerprints. The conditions inwhich the photographs were made were held constant throughout allthe period of the analysis: the aperture was set to f/25 and the ISOsensitivity to 200.

2.7. Evaluation method

Concerning the marks’ analysis, a scoring was established so as toevaluate the quality of the observed mark. The hand was divided in 6areas (the five fingers and the palm area) and a score was assigned toeach area. The scoring in use is the one used by the Ecole des SciencesCriminelles de Lausanne [13]. Each mark was scored from 0 to 3 ac-cording to the criteria detailed in Table 3.

Note that for the fingers, only the distal areas had been scored andnot the proximal and intermediate phalanges from which good qualitymarks were sometimes developed.

3. Results and discussion

3.1. One day ageing fingermarks

Concerning nitrile gloves, the wet powder method shows greatereffectiveness than the ninhydrin or 1,2-Indanedione/ZnCl2 solutionstested (Table 4).

Concerning latex gloves, wet powder is far less effective than withnitrile gloves but remains significantly the best method (Table 5).However, the ninhydrin solution seems to work better than with nitrilegloves. This can be attributed to the fact that latex gloves are lighterand probably more porous to the solvent system. There may be moreabsorption of secretion and reagent, thus making the visualisation ofmarks using ninhydrin easier on latex gloves, whereas some of the ni-trile gloves used in this study were slightly dark.

The results obtained for vinyl gloves are presented in Table 6. Al-though not statistically representative as they were conducted on asingle type of gloves, they show a greater efficiency of the IND-Zn 1

solution as wet powder and ninhydrin 2 did not enable the visualisationof any mark. Fig. 1 shows examples of marks developed during thetests.

Table 2Ninhydrine and 1,2-Indanedione/ZnCl2 formulations.

IND-Zn1 IND-Zn2 (stock) IND-Zn2 Ninhydrin1 Ninhydrin2 (stock) Ninhydrin2

1,2-indanedione powder 0.4 g 0.125 g – – – –Ninhydrin powder – – – 2 g 5 g –Acetic acid 5 mL 5 mL – 5 mL 5 mL –Ethyl acetate 45 mL 50 mL – 35 mL 2 mL –HFE-7100 410 mL 400 mL – 450 mL – 250 mLEthanol – – – 10 mL 45 mL –Methanol – 50 mL – – – –IND-Zn 2 stock – – 100 mL – – –Ninhydrin 2 stock – – – – – 13 mLZnCl2 solution 40 mL – 2 mL – – –

Table 3Evaluation method.

Score Description

0 No ridges are visible at all, no sign of fingermark.1 Ridges are visible over a small area of the mark or over the whole mark, but it is extremely difficult to retrieve second level characteristics (such as minutiae) due to

extremely poor ridge details.2 Ridges are visible on almost the whole area of the mark, and second level characteristics can be retrieved. Nevertheless, the quality is not optimal due to a low contrast

(strong background staining or faint ridges).3 Ridges are very well defined on the whole mark. Second level characteristics can easily be retrieved. The contrast is optimal with no (or extremely faint) background

staining.

Table 4Results for nitrile gloves (one day ageing marks).

Bearing METHODE Score Number of marks Average score

0 1 2 3

1 Ninhydrin 2 251 36 12 1 300 0,21 Wet powder 90 94 50 66 300 1,32 IND-Zn 2 201 51 26 22 300 0,62 Wet powder 81 92 73 54 300 1,33 IND-Zn 1 156 71 42 31 300 0,83 Wet powder 93 94 39 74 300 1,3

Table 5Results for latex gloves (one day ageing marks).


0 1 2 3


Table 6Results for vinyl gloves (one day ageing marks).


0 1 2 3



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Fig. 1. Examples of one day ageing fingermarks (from left to right: glove 6, nitrile, wet powder/glove 12, latex, wet powder/glove 16, vinyl, Ind Zn 1/glove 12, latex,Ninhydrin 2).

Fig. 2. Examples of one week ageing fingermarks (from left to right: glove 1, nitrile, wet powder/glove 11, latex, wet powder/glove 9, nitrile, wet powder/glove 10,nitrile, wet powder).

Graph 1. Comparison of the scored one day ageing marks for all gloves.


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Graph 1 recaps the results obtained on all types of gloves (nitrile,latex and vinyl) and gives the percentage of marks scored 0, 1, 2 or 3 foreach treatment. The wet powder results correspond to an average of thescores obtained during the 3 comparative tests.

3.2. One week ageing marks

Given the results, only one of the 1,2-indanedione solution has beenkept for the subsequent tests. Indeed, IND-Zn 1 provided better resultson recent marks than IND-ZN 2.

As with the results obtained after one day, wet powder remains themost effective development method on nitrile gloves (Table 7) and latexgloves (Table 8). However, this method has not enabled the

visualisation of any marks on vinyl gloves, unlike the ninhydrin 1 so-lution and the IND-Zn 1 solution, which have shown 3 low-qualitymarks (Table 9).

Graph 2 recaps the results obtained on all types of gloves (nitrile,latex and vinyl) and gives the percentage of marks scored 0, 1, 2 or 3 foreach method. The wet powder results correspond to an average of thescores obtained during the 2 comparative tests. Fig. 2 shows examplesof marks visualized during the tests.

3.3. One month ageing fingerprints

The results obtained on more recent marks are confirmed with onemonth ageing marks. Wet powder is the most effective technique on

Table 7Results for nitrile gloves (one week ageing marks).


0 1 2 3

1 Ninhydrin 2 290 8 2 0 300 0,01 Wet powder 74 108 58 60 300 1,32 IND-Zn 1 192 62 28 18 300 0,62 Wet powder 77 91 77 55 300 1,4

Table 8Results for latex gloves (one week ageing marks).


0 1 2 3


Table 9Results for vinyl gloves (one week ageing marks).


0 1 2 3


Graph 2. Comparison of the scored one week ageing marks for all gloves.

Table 10Results for nitrile gloves (one month ageing marks).

Bearing METHODE Score Number of prints Average score

0 1 2 3


Table 11Results for latex gloves (one month ageing marks).


0 1 2 3


Table 12Results for vinyl gloves (one month ageing marks).


0 1 2 3



477

nitrile gloves (Table 10) and latex gloves (Table 11). On the contrary,this method is not effective on the vinyl gloves from our sample. Onlythe Indanedione solution allows the visualisation of a few marks(Table 12).

Graph 3 recaps the results obtained on all types of gloves (nitrile,latex and vinyl) and gives the percentage of marks scored 0, 1, 2 or 3 foreach method. The wet powder results correspond to an average of thescores obtained during the 2 comparative tests.

The analysis of the results for all types of gloves show a stability ofthe results obtained with Wet Powder up to a month time, unlike to theninhydrin and indanedione solutions (Graph 4). These differences in theefficiency of treatments may be related to differences in targetedcompounds. Exact mechanism of wet powder is unknow as yet but it isreasonable to assume that the greasy substances of the mark play a partin the development when indanedione and ninhydrin react with aminoacids. Amino acids could deteriorate or interact with the glove moreeasily than greasy substances over a short time (less than one month).We may also consider that this could be caused by the microstructureand porosity of the gloves. Therefore, greasy substances quite probablystay at the surface and penetrate the interior of the glove less easily,facilitating their visualisation.

However, results remain highly conditional to the type of glove andthe material has a significant role to play. Table 13 and Graph 5 recapthe results obtained per glove for 24 h ageing marks. An analysis of theresults obtained with wet powder shows that this treatment works wellon nitrile gloves except for gloves No. 5 which are black and for whichblack wet powder was replaced by white wet powder. The latter ob-viously seems less effective, thus confirming a tendency already ob-served on adhesives as part of our real cases. Wet powder results areweaker on latex gloves and unsuccessful on the vinyl gloves sample.The indanedione solution works on some nitrile gloves and only givessatisfactory results on one latex glove (No. 12) and the vinyl glove (No.16). Ninhydrin, which is overall the least effective method, providesalmost no results on nitrile gloves, only provides positive results on 2latex gloves (Nos. 12 and 13), and remains ineffective on vinyl. The

Graph 3. Comparison of the scored one month ageing marks for all gloves.

Graph 4. Average score as a function of ageing (for all gloves).

Table 13Average score (one day ageing marks).

Glove Material Wetpowder Ninhydrin 2 IND-Zn1

1 Nitrile 0.9 0.0 0.52 Nitrile 1.9 0.7 1.13 Nitrile 1.7 0.0 1.84 Nitrile 1.4 0.0 0.45 Nitrile 0.0 0.0 2.06 Nitrile 0.8 0.1 0.87 Nitrile 1.4 0.1 0.18 Nitrile 1.2 0.0 0.69 Nitrile 2.3 1.1 0.810 Nitrile 1.6 0.1 0.311 Latex 1.1 0.1 0.112 Latex 0.5 1.4 1.213 Latex 1.1 1.0 0.314 Latex 0.0 0.4 0.315 Latex 0.3 0.0 0.016 Vinyl 0.0 0.0 1.1


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color of the glove is undoubtedly a determining factor on the ability toobserve ninhydrin-developed marks. Thus, dark gloves (No. 5 or No. 7)offer no positive result but the same can be said about some whitegloves. In this case, the white gloves are sterile which involve a specificmanufacturing process and can be a part of the explanation. The colorof the glove cannot therefore be regarded as the only cause. Powderedgloves (Nos. 12, 13 and 14) provide few results which must be due tothe fact that powder absorbs secretions. A weak luminescence of the1,2-indanedione can be observed on glove No. 13, as if the reaction didnot occur. Furthermore, it has been observed that, in general, back-ground noise was more important on latex gloves (Nos. 11, 12, 13, 14and 15) than on nitrile gloves. From these results, a practitioner in thefield should use wet powder, in particular, if he is not sure in the ma-terial.

4. Conclusion

Among the different techniques used in this study, visualisationusing wet powder stands as the most effective on our panel of gloves.This technique provides very positive results on nitrile and latex glovesand seems less sensitive to the ageing of marks than techniques tar-geting amino acids. However, its use is limited when used on darkgloves and vinyl gloves for which a specific HFE-7100-based 1,2-in-danedione formulation is favored. It must be concluded that the ma-terial definitely has an effect on the effectiveness of visualisation butthat other factors (color, powder) must also be taken into account. Thisvariability also seems to depend on other intrinsic characteristics of theglove, including its microstructure, which could explain the differencesregarding reaction and background noise.

CRediT authorship contribution statement

Mélina Rousseau: Investigation. Pierre Ledroit:Conceptualization, Methodology, Validation, Writing - original draft.Marianne Malo:Methodology. Damien Henrot:Methodology. HélèneGuille: Writing - review & editing.

Acknowledgements

The authors would like to thank Mrs Jehanne Ranvier for her as-sistance in translating this publication.

Appendix A. Supplementary data

Supplementary data to this article can be found online at https://doi.org/10.1016/j.scijus.2020.07.002.

References

[1] R. Ramatowski, Lee, Gaensslen’s, Advances in fingerprint technology, in: CRC Seriesin Forensic and Police Science, second ed., CRC Press, Boca Raton, Fla, 2001, pp.172–173.

[2] J. Pleckaitis, Developing friction ridge detail on the interior of latex and nitrilegloves, J. Forensic Ident. 57 (2) (2007) 230–239.

[3] J. Pressy, Ninhydrine on latex gloves: an alternative use for an old technique, J.Forensic Ident. 49 (3) (1999) 257–260.

[4] D. Rinehart, Developing and identifying a latent print recovered from a piece oflatex glove using ninhydrine-heptane carrier (case 1). Developing latent prints onhousehold rubber gloves using ninhydrine-heptane carrier after superglue fuming(case 2), J. Forensic Ident. 50 (5) (2000) 443–446.

[5] T. Arbeli, Y. Liptz, R. Bengiat, M. Levin-Elad, Development of fingermarks on Latexgloves: the solution to a challenging surface, Forensic Sci. Int. 280 (2017) 147–152.

[6] M.J.M. Velders, Visualization of latent fngerprints on used vinyl and latex glovesusing Gellifters, IAI Educational Conference, ST LOUIS, 2004.

[7] C. Champod, C. Lennard, P. Margot, et al., Traces et empreintes digitales, traité dedactyloscopie, Presses polytechniques et universitaires romandes (2017) 241–253.

[8] M. Scoot, C.A. Does, Fuming interfere with powder suspension processing? J.Forensic Ident. 59 (2009) 144–151.

[9] R. Ramatowski, A.A. Cantu, M.M. Joullie, O. Petrovskaia, 1,2-Indanediones: apreliminary evaluation of a new class of amino acid visualizing compounds,Fingerprint Whorld 23 (1997) 131–140.

[10] C. Roux, N. Jones, C. Lennard, M. Stoilovic, Evaluation of 1,2-Indanedione and 5,6-Dimethoxy-1,2-Indanedione for the detection of latent fingerprints on porous sur-faces, J. Forensic Sci. 45 (2000) 761–769.

[11] P. Ledroit, D. Henrot, M. Malo, Usefull working tool to develop fingerprints onadhesives tapes with powder suspensions, Can. Soc. Sci. 52 (3) (2019) 101–105.

[12] International Fingerprint Research Group, Guidelines for the assessment of finger-mark detection techniques, J. Forensic Ident. 64 (2) (2014) 174–200.

[13] A. Becue, A. Scoundrianos, S. Moret, Detection of fingermarks by colloidal gold(MMD/SMD) beyond the pH 3 limit, Forensic Sci. Int. 219 (1) (2012) 39–49.

Graph 5. Average score (one day ageing marks).


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