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A fluorogenic method for lifting, enhancing, and preserving bloody impression evidence


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This paper describes the use of Zar-Pro fluorogenic lifting strips that can be used on bloody impression evidence. These easy-to-use strips successfully lift and enhance bloody impressions from a variety of substrates, regardless of porosity or background color. The lifting strips are highly sensitive and fluoresce when coupled with proteins and excited with an alternate light source.
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Journal of Forensic Identif ication
260 / 61 (3), 2011
1 Midwest Forensics Resource Center, Research Project, Madonna
University, Livonia, MI
2 Michigan State Police, Northville Crime Laboratory, Northville, MI
Re ce iv ed Ju ne 10, 2010; a cce pte d Sep tem ber 25, 2010
Technical Note
A Fluorogenic Method for Lifting, Enhancing,
and Preserving Bloody Impression Evidence
Jessica Zarate 1
Charles Morden 2
Abst r ac t: Thi s pap er de scr ibe s t he u se of Zar-P ro f luoro ge n ic l ift-
in g st rip s th at ca n be us ed on bl ood y impr ession evid enc e. The se
ea sy-to - use str ips succe s sf u l ly lif t a nd enha nce bloo dy impr essio ns
from a var iet y of sub stra tes , reg ard less of po ros it y or background
color. T he lif t i ng st r ips ar e h igh ly sen sit ive a nd f luo res ce wh en cou -
pled w ith pr oteins an d excit ed wit h an alt erna te lig ht sourc e.
Introduct i on
Current blood enhance me nt methods vary in effectiveness and
there is no un iversally accepted procedure for lif ting, en hancing,
or preserving bloody impre ssion evidence. In most cases, foren-
sic an alyst s deter mine t he optimal processi ng me tho d based on
the desire d cont rast (someti mes using the f luorescent prop erties
of t he i mpression or s ubstrate), the porosit y of t he s ubstrate, the
safet y of the blood enhancement chemicals, the ease of preparing
and apply i ng the re agent s, and the avai labil it y of equipme nt and
laboratory re sou rce s [1].
Photog r aph ing impre ssion ev idence i s u sual ly the first step
in its preservation. Some blo ody im pre ssions may retain su ffi-
cient color to be visuali zed and photographe d w ithout t he ne ed
for subsequent enhancement. Often , however, a pho tog raph of
the i m pression is not a dequ a t e b ecau s e of a lack of cont r a st
Journal of Forensic Identif ication
61 (3), 2011 \ 261
between the impression and the background . In the se inst ances,
en h ance ment me thod s are needed t o imp rove t he c ont r a st for
visua lization of i mpression de tails.
The ability of some enhancement methods to achieve f luores-
ce nce is ben ef ici al. Blood is no t n atu rally f luo resc e nt whe n
vis u alized wit h an alt er n ate lig h t s ource (ALS) [2, 3], even
though it c ontai n s s ome plasma pr otei n s [4, 5 ]. So me of the
prot ein s that are fou nd in blood plasma are com posed of ami no
acids (e.g., phenylalanine, tyrosine, and t r y ptophan) that contain
intri nsic f luorophores [68]. Even with the pre sence of int r insic
f luorophores, bloody impre ssion s absorb light t hat da rkens the
impressio n detai ls whe n visu a lized w ith an ALS [1, 9]. T h i s
da rkening provides an effect ive cont rast on some f luorescent or
light subst rate s w ithout the need fo r s ubs equent enha nce ment
[9]. Howeve r, w hen co ntras t between the i mpre s sion and t he
subst rate ca n not be achieved, f luorogenic blood enhan cem ent
methods ca n be used.
The resu lting f luore scence achie ved by f luo rogenic blood
en hancement chem icals is of ten preferred over nonf luo rogen ic
metho d s bec ause of i ts hig h sen sit ivit y, which al lows for the
vi suali z atio n of i mpre ssion det ails t h at are n ot visible under
norma l l ighting condit ions. Fluorogen ic enha nce ment can also
optimi ze i mpre ssion det ails by imp roving contras t an d elimi-
nating distrac t ing background s. Some of the n egative a spe cts
wi th current f luorogen ic met hods are t hey va r y i n i n tensity,
the resu lti ng f luorescence is ofte n shor t lived, and the en h anc e-
ment process may alt er or destroy the impre ssion e vidence. As
a result, f luorogenica lly en hanced imp res sions usual ly require
im mediat e photography t o preserve the impressio n.
The overall effectiveness of enh ancement methods is affected
by t he porosit y of the su bst r ate. The degre e of porosit y af fects
the absor pt ion a nd di ffusion of enha ncement chemicals, depend-
ing on the chemical comp osition and processi ng me tho d [1].
It is a com mon practice in forensics to l ift nonblood impres-
sion s fro m s ubst ra t es using v a r iou s l i f t i ng medi a . However,
prev iously, these lif ting te chniqu es have not been succ essfully
appl ied to bloody impres sions. Si nce 1987, for ensic scient ist s
have been tryi ng to creat e an effect ive met hod for lif ting bloody
impressio ns, but to d ate have ha d limited s uccess [1, 2 , 10 12].
Cu r r ent met hods lack du r abilit y, pra cticality, s ensitivit y, and
the ability to preserve the lifted impression for f uture analysis .
Journal of Forensic Identif ication
262 / 61 (3), 2011
The ef fectiveness of the re c e ntly developed f l uorog e n ic
bloo d-l ifting strips (Z a r-Pro1, Livon ia, MI) is due, i n part, t o
th e c ompo sit ion of t itanium dioxide i n t he lifting mat er ials .
Tit a niu m diox ide c reates an adhe sive bo nd wit h biomole cules,
su ch as t he plasma prot eins found i n blood [4 , 5]. It has al so
be e n u s ed i n sm a ll p a r t icl e form a s a n enhanc ement chemi-
ca l for no nblood lat e nt im pres sions on both t he adhesive a nd
nona d hesive side s of dark- colo red tape [13 –15] and ot her da rk,
nonporous substrates [14, 16].
Bloo dy impres sions have also been s ucc essf u lly e n hance d
with the use of titan ium dioxide. This technique has been li mited
in effect iveness to mostly da rk, nonporou s substrate s [16]. As a n
en hancement chem ical, titanium dioxide in small p article for m
is con sis tent and effective. Its fine, wh ite powde r is nontox ic
and non f lammable [13, 14], but recom mended wor king solut ions
cont ain pur e a n hydrous met hanol, which is f la m mable an d not
recommended for use at cr i me scenes [1, 17]. Tit anium dioxide is
also not n aturally f luorescent and in this form can not be f luoro-
genically en hanced throug h visu ali zat ion w ith an A LS.
Fluoroge nic lif t ing strips a re u n ique b ecause they a re intrin-
sicall y f l uore s c ent and d o no t re q u i r e ex t r i ns ic f luo roge n ic
en hance ment chem icals. The intri nsic f luore scence of the lif t ing
st r ips i s belie ve d to be attrib uted to a phenome non k now n as
metal-en h anced f luor escenc e. Bloo dy and ot her proteina ceous
secretions contain f luor ophores, components of a molecu le t hat
caus e t he mole cule to be f luores cent. Whe n t hese f luorophores
are i m mobilize d w ith i n close prox imit y t o certai n meta ls, they
can be excit ed with an ALS [6 –8 , 18]. T he interaction b etween
prot ein -intrinsic f luoro phore s a nd met al cre ate s h igh -inten sity
f luore scence, wh ich has been repor ted t o dramatically i ncrease
f luore scent capa bilit ies [7, 18].
Th e objective s of th is r esea rch we re t o an aly ze t he f luoro -
genic blood-li fting s trip s’ (1) a bilit y to li f t blood y i mpr essions
fr om a variety of substrates with various degrees of poro sity, (2)
abil ity to l ift aged bloody impre ssions from various s ubstrates,
(3) abilitiy t o f luor esc e t he lif t ed aged and diluted imp ression s
when illuminate d with an A LS a t 505 n m , and (4) se nsitivit y on
wate r-diluted bloody impression s.
The author, Jessica Zarate, researched and developed the Zar-Pro product and
Journal of Forensic Identif ication
61 (3), 2011 \ 263
Materia ls and Metho ds
Zar-P ro Fl uoregenic Lifting Str ips
The lifti ng strips are ma nufact u red in sheets and cut to siz e
ac cor ding to u se. Sm aller s t r ips can be cut f rom a la rge sh eet
for f ingerpr i nts or the la rge shee ts can be left u ncu t for la rge r
ha ndpr i nts or foot wear i mpr ession s. T h e st r i ps a r e co mposed
of wh ite nylon tra nsfer membranes with a spe cializ ed chemical
formul atio n that i s bond ed to the m emb r a ne and i s activate d
with a 50:50 methanol (l aborator y gra de, Fl i nn Scientif ic Inc.,
Batavia, Ill inois) and water solution. Trials were also condu cted
with a 50:50 ethanol (labo rato r y g rade, Flinn S cie ntif ic Inc.,
Ba t a v i a , Il l i noi s) and wa t e r solution that wa s fo u n d to be
su itable, but not a p referred a lter na tive to the meth a nol. The
wh ite bac kgro und of t he l i f ting strip provides a nice contrast
for the lifted bloody impression s un der normal lighting cond i-
tion s while also abso rbi ng light when visual ized with an A LS,
pr ovi d i ng a con t r asting d a r k backg r ound for the fl uor e scen t
imp ression . T h e l i f ted i mpre ssions are affixe d t o t h e l if ting
st r ips and cannot easi ly be s cratched o r alt ered, i n a manner
similar to t hat of a photog raph. It is also i mpo r tant to note t hat
the li f ted i mpressions need to be lat erally rever sed, sim ilar to a
gel-l ifte r or ca sti ng ma ter ial. The l ifting str ips have a sh el f life
of at least six months pr ior to use, a nd the lif ted impressions are
preserved af ter nearly two year s in the same condition with their
f luorogenic properties st ill viable for an alysis.
The blood u s e d in t h i s study was dr awn by a l aborat o r y
te chnic ian. The blo o d samples were take n i ntravenously and
draw n d i rectly i nto pu r ple top (ant icoa g u lant) tube s (7.2 m g
BD Vacut ainer br and g lass collect ion tube wit h K 2 EDTA). Th e
tubes of blood were s tored and refriger ate d bet wee n use s in the
labo rat ory ref r igerator se t between 38 t o 4 0 °F. Blo od samples
were refrigerated for no more than one week to prevent degra da-
tion. Before impression s were dep osite d, t he blood was warmed
in the t u bes via wate r bath to approximately 98 °F a nd sha ken
thor oug hly t o mix the contents. Fresh blood s amples we re also
used with t he lif t ing st r ip in l ie u of the sa mples with K 2EDTA
to demonst r ate t h at t he ant ico agula nts d id not fa ctor into the
effectivene ss of t he lif ting s trip s.
Journal of Forensic Identif ication
264 / 61 (3), 2011
Su bst rat es
The sub st r ates wer e ch o sen for anal ysis bec a u se of t heir
su r fa c e t ype (i.e., t hey ofte n pre s ent pro ble m s for e n h a nce-
ment a nd v isua lizat ion) and beca use t hey can be en cou ntered
at c r ime scenes. The n onpor ous subst rat es included alumi num,
bla ck plastic, blue plastic, glass , steel sheet metal, linoleu m, a nd
glazed ceramic ti le. T he sem iporous subst r ates i ncluded painted
drywa l l, two sample s of brown le athe r, t wo s a mples of black
leat her, brown vinyl, black vinyl, hu man ski n (inne r for earm),
painted concrete, glossy paper, a nd stai ned wood. (Two sa mples
of both b row n and bla ck leat her were ch ose n fo r the res earc h
tria ls be cause of t he inc onsiste nt re s ult s obt a i ned i n a pre v i-
ou s rese a rch , i n which tit a n ium dioxide wa s u sed to d evelo p
blo ody i mpr essions on d a rk su r faces. The study ana lyzed three
black leat her samples and two br ow n le ather s ample s, a nd the
results were incon sistent [16]. The leather sample s were f u r t her
select ed becau se of their dif ferences in coloration, t ext u re, and
gener al c omp osition.) The por ous substrat es in cl ude d ca nva s,
nylon, den i m, an d cotton fa bric. E ach sub strate ha d a tot a l of
40 i mpr essions de posited for analy sis.
De posit ion Parameters
Opti mal qualit y bloo dy impressions were made on the variou s
subst r ates u sing set para mete rs, d epend ing on the sub strat e’s
surface texture and porosit y. The var iables control led throughout
the re search trials involved blood volume s, sk in and lab tempera-
tur es, pre- a nd p ost dep osition waiting int erva ls, and depo sition
pressure. The de posit ion meth odology wa s based on a r ese arch
st udy specif ica lly pertaining to t he de position of blo ody impres-
sio ns [19]. T he s ubstrate i mpr ession a nd d ilution t r ials were left
to dr y for one hour before ap plying t he lif t i ng st r ips . T he aged
imp ression trials were lef t for one hou r, one d ay, one week,
one m ont h, t h r ee m ont hs, a nd six mont hs b efore apply i ng t he
li f ting st r ips. Reproducibility of impressio n e vid enc e i s di ff i-
cult , but the dep osition para met ers wer e se t to c reate consistent
and compar able optimal qualit y impressions for analysis of the
subst r ate a nd aged i m pre ssion t r i als. The d ilut ion trial s we re
conducted for obser vational purposes a nd were not collectively
ra t ed b e caus e of t h e d i f f iculty of cont rol l i ng t he depositio n
quality with the w ater-dilut ed impression s.
Journal of Forensic Identif ication
61 (3), 2011 \ 265
Applic ation and Lif t ing Process
The l ifting strips wer e removed f rom the plastic storage bags
and activated with the metha nol and water solution. The activat-
in g solu t ion wa s applie d dire ctl y to t he l ifting strip s, using a
pump st yle spr ay bottle. T he st r ips wer e misted until t hey wer e
completely satura ted . T he lif t ing st r ips should only b e hand le d
with nit r ile glove s. La tex glove s contain prot eins t hat c an be
tra n sferred to t he l ifting strips, leaving a p rot ein residu e th at
can be vi sua lize d with an A LS. Up on sat u ration , the strip s were
ai r- d r ied sl ightly to eli m i nat e any visible pooling of s olution.
The lif ting strips were place d direc t ly on t op of t h e b loo d y
im pre ssion s with the act ivation side dow n. Ade quat e p ressure
was applied to en sure bond ing was complet e. The l ifting strips
were t hen removed from t he subst rat e.
Visu aliza tion with an ALS
The ALS used in this project was a Rofi n Polilight (Melbou rne,
Aust r alia). Th e i mpr essions we re vis ual i zed at 505 nm wit h a n
orange bar rie r f ilter. Th e prope r tie s of the l ifting st r ips created
br ightly f luor escent bloody impres sions with hig h c ont rast for
visua lization with mini mal back grou nd inter fer ence.
Resu lts and Di scussion
Su bst rat e Impre ssi on Trials
The age d impr ession t r ials were conduct ed on t went y-t wo
subs trates. For t y impressions we re dep osited on each substra te
for a tot al of 880 impression s t hat were li f ted for ana lysis. The
nonp orous substrat es produced identif iable l ifte d impressions
th at had exc ept ional clarity a nd contra st on all of the su bst rate
tri als. Most of the s emiporous subst rat es als o p roduced excep -
tion al lif ted impression s ( Figure s 1 5). The black vinyl had a
roug h textured backgr ound that caused some of the r idge det ail
in the li f ted impression s to be dis r upted, but the overall i mpr es-
sion pat terns were still visible in the majority of the lifts (Fig ure
So m e of t h e porous su b s t r ates (ny lon and c ot t o n) al s o
produce d identif iable i mpressions that had except ional clarit y
and c onstrast (Figure 6). D enim prod uced some iden t if iable
lifte d impressions (Fig u re 7), but the majorit y of t he lif t s had no
visible ridge deta il. T he da rk ba ckg rou nd and prominent weave
pat tern in the de n i m made i t difficu lt to d etermine t he print
qu ality while depositing the blood impression. Ca nv as did not
Journal of Forensic Identif ication
266 / 61 (3), 2011
produ ce identifia ble impres sions i n the major ity of th e tria ls.
Some lift s from the canvas displayed over all impression patterns
and ridge pat h, but most displayed blo ody we ave patter n s repli-
cating the clo sely bound patter n in the fabr ic. Overall, 19 of the
22 s ubs t rat es produc ed lifts with i ndividual i zing ridge detai ls
th at ha d exceptional cla r it y and contra st (Table 1).
Nonp orous Subst rates:
Alu mi num * **
Blac k Plast ic ***
Blue Plast ic ***
Gla ss ***
Sea led Til es ***
Met al ***
Lin oleu m ***
Sem iporou s Subs trate s:
Sta ined Wo od ***
Pai nted C oncret e ***
Brow n Lea ther #1 ***
Brow n Lea ther # 2 ***
Blac k Leat her #1 ***
Blac k Leat her #2 ***
Hum an Ski n ***
Pai nted D rywa ll * **
Brow n Viny l ***
Blac k Vinyl **
Glos sy Pap er ***
Poro us Sub strat es:
Nylo n ***
Cot ton * **
Den im *
Can vas *
0 = no vis ible pr otein aceou s mate rial, no vis ible ri dge det ail
* = visib le prot einac eous m ateri al, no visibl e ridg e deta il
** = visibl e prote inac eous ma teri al, vi sible r idge de tail i nclud ing som e ridg e
path s or i mpress ion pat tern
*** = v isible prote inace ous ma teria l, vis ible ri dge det ail i ncludi ng imp ressio n
pat tern a nd rid ge pat h with clear detai ls
Table 1
Substrate lift quality; visualized under normal lighting conditions.
Th e li f t ing strips demon strated a br oad range of effective-
ness on s ubstrates w it h va r ious degrees of porosity. The tex t u re
of the su bst rate af fe cte d t he lift qu ality mor e t han the porosity
did. T he l ifted impr essions th at were of the bes t qu alit y we re
from subs trat es with l ittle or no b ackground tex t ure (e.g., black
pl astic, aluminum, se a led tile , smoo t h leat h e r s, and glossy
paper) ( Figu res 3b and 4b). Substrates th at were slightly af fected
Journal of Forensic Identif ication
61 (3), 2011 \ 267
by backg rou nd texture we re the st a ine d wood, painted d r y wal l,
and painted concrete. Ma ny of these substrates had some isolat ed
occu rrences such as clu mps in pai nt , bubbles f rom stain, crea ses,
scratches, o r oth er si mila r mark s ( Figure 1b). The backg rounds
in these subst rates d id not h ind er the lif t q uality bec aus e most
were isolat ed occu r ren ces. T he substrates with slightly text u red
or pat t er ned back g rou nds (e.g., blu e plast ic, l inoleu m , brown
leather #1, brow n vinyl, human skin, nylon, and cot ton) produced
identifia ble li f ts w ithout affecti ng t he ove rall lif t qua lit y, but
evid enc e of t he bac kground pa t terns were visible (Figures 5a,
5b, 6a). The more prominent textured and pat ter ned backgrounds
(e.g., black vinyl, den i m, a nd c a nvas) a ffe cted the lift qual ity
to t he point tha t the background pat t erns disrupted much of the
impressio n det ail (Fig u res 2b and 7b).
Subst r ate p orosit y d id n ot af fect lift q u alit y; howeve r, t he
degree of p orosity did det ermine whether the e nti re imp ression
could be li f t ed f rom the s ubst rat es. Li f t ed impr e ssions from
no nporo us and sem i p orou s sub st r ates had l it tle to n o blood
resid ue left on the substrates (Figures 1a, 2a, 3a), wit h the excep-
tion of glo ssy paper (Fig u re 4a). Gloss y paper was categor i zed
as se mip orous becaus e of its shiny protective coating, but based
on its deg ree of porosit y, it was mor e poro us t han some of the
othe r s emipor ous subst rates. The othe r p orous subst r ates (e.g.,
nylon , denim, cotton, and ca nvas) all left visible blood resid ue
on the s ubstrates ( Figure s 6a an d 7a). W hen l ifting impression s
from por ous s ubstrat e s , the lifting strips worke d bes t wh e n
increase d pressur e was ap pl ied to f u r t her bond the lifti ng strip
to t he impression.
(a) (b)
Figure 1
Wood: (a) substrate after the lift; (b) blood lift.
Journal of Forensic Identif ication
268 / 61 (3), 2011
(a) (b)
Figure 2
Black vinyl: (a) substrate after the lift; (b) blood lift.
(a) (b)
Figure 3
Brown leather #1: (a) substrate after the lift; (b) blood lift.
(a) (b)
Figure 4
Glossy paper: (a) substrate after the lift; (b) blood lift.
Journal of Forensic Identif ication
61 (3), 2011 \ 269
(a) (b)
Figure 5
Human skin: (a) blood lift; (b) close-up of blood lift.
(a) (b)
Figure 6
Nylon: (a) substrate after the lift; (b) blood lift.
(a) (b)
Figure 7
Denim: (a) substrate after the lift; (b) blood lift.
Journal of Forensic Identif ication
270 / 61 (3), 2011
Age d Impressi on Tri als
Bloo dy impr ession s were d e posited o n six surfa ces: t h ree
nonp orous (aluminu m, black plas tic, and me t al), t wo semipo-
rous ( bla ck lea t her and wood), and one p orou s (c otton). T h e
six surfa ces were sele cted as a represent ative sample f rom the
subst r ate impr ess ion tria ls. The six sub strat es h ad te n bloo dy
impressions deposited for each int erva l i n the age d i mpr ession
tr ials. They were lef t for one hour, one day, one week, one month,
th r ee mont h s, an d si x mo nths befor e lif t i ng for a tot al of 360
lifted impressions. Subs equent e n hancement was conducte d o n
aged impressions that were fai nt or inv isible under norma l light-
ing conditions thr oug h f luorogenic enha nce ment with an ALS.
The l ifti ng strips were effect ive on the nonporous substrate
tr ials. The lif ted bloody impres sions for samples aged one month
from alu minu m, black plastic, and metal di splayed identif iable
impressions that ha d exceptional clarity and contra st (Figure 8b).
The thre e - and six-mon th li f t s fro m the nonpor ous subst rate s
were fa int , but the major ity of the ove rall impression pat terns
were st ill visible. T he bloody im pre ssion on metal (Fig u r e 9a)
shows how fa ded the imp ression is, yet it still f luore sced (Fig u re
Th e l iftin g strip s were also ef fec tive on the majorit y of t he
semip orous sub stra te t r ial s. The lif t ed bloody im pre ssion s for
sample s aged for one mont h from black leather dis played identi-
fiable imp ressions tha t h ad exc e ptio nal clarity and co ntrast .
The t h r e e- a nd six-mont h l i f t s f rom black le athe r were fa i nt
(Fig ure 10a), but the major ity of the l ifts st ill produced visible
impression patter ns. Staine d woo d d id no t prod uce the s ame
quality l ifte d impre ssion s. T he major ity of t he lifts throug h one
day of agi ng displayed ide nti f iable i mpressions t hat h ad exce p -
tion al cla rit y and contra st. After one week, howeve r, the bloo dy
im pre ssions dep osited on t he stain ed wood began to fade; the
st a in on the wood a ppea r ed to be ab sorbing t h e blood. A f t e r
only one week, the bloody imp res sions were not readi ly visible
without the use of oblique l ight i ng. Because of th i s rea c tio n,
th e majorit y of th e lifted i mpre ssions fro m the s t ained wood
displayed only the over all impre ssion patt ern. By the one-mont h
inter val, the majority of t he li fting strips displayed only a faint
amou nt of bloo d and had no r idge det ail visible. At three and six
mont hs, there wa s no v isible remna nt of blo od on the majorit y
of the l ifting strips.
Porous cotton pro duced identifiable lif ts f rom sa mple s a ged
for one mont h. T he major ity of the li f ts d isplaye d identifiable
Journal of Forensic Identif ication
61 (3), 2011 \ 271
impressio ns. By th ree a nd six mont hs, t he majorit y of the lifted
bloo dy i m pre ssions u nder nor ma l light d isplayed only a fai nt
amou nt of blood and had vi sible rid ge detai ls (Fig u re 11b).
The lifti ng st r ips de monst r ate d t hei r effect iveness in lif ting
bloo d y i mpre s sions f rom mo st of the s ubst r a tes throu g h one
mont h of aging wit h th e exception of the st a ined wood. Many
of t hese lif ted i mpr essions a ged thro ugh one month dis played
ide nt ifiable ridge det ail and had exceptional clarity and contra st.
Lifte d impressions wer e faint, but visible, th rou gh t h ree and si x
months of agi ng fro m most of t he subst rat es with the exception
of wo od and c otton (Table 2). The a nalyses of these l ifte d age d
impressio ns were conduct ed under normal l ighting conditions.
Age d Impre ssion s - Lif t Qual ity ( Norma l Light ing C ondit ions)
Subs trate s 1 Hou r 1 Day 1 Wee k 1 Mon th 3 Month s 6 Mo nths
Nonp orous: Alum inum *** *** *** *** ** **
Nonp orous: Black Plasti c *** *** *** *** ** **
Nonp orous: Metal *** *** *** *** ** **
Sem iporou s: Sta ined Wo od *** *** ** * 0 0
Sem iporou s: Blac k Leat her *** *** *** *** ** **
Poro us: Cot ton *** *** *** *** * *
0 = no vi sible p rotein aceou s mate rial , no vis ible r idge de tail
* = visi ble prot eina ceous mater ial, n o visib le ridg e deta il
** = visib le prot einac eous m ateri al, vi sible r idge d etail includ ing so me rid ge pat hs or i mpress ion pat ter n
*** = visibl e prote inace ous ma teri al, vi sible r idge de tail i nclud ing im pressi on pat tern and ri dge pat h with clear detai ls
Table 2
Lift quality: visualized with normal lighting conditions.
The lifted impre s sio n s that wer e fa i nt or inv i sible u nd e r
normal lig ht i ng condition s wer e subsequently enhanced throug h
visua lization with an A LS to take a dva ntage of t he f luores cent
prop erty of the li f ting st r ips. The enha nced i mpr essions we re
consistent in fluorescent i ntensity and cont rast and had mini mal
ba ckg r ound interfe renc e a mon g each of the s ubst r ates in the
aged impres sion trials. The fluorescent or ange or yellow impres-
sions were v isu aliz ed on the dar k, lig ht-ab sorbent background
of the lif t ing strips, creating opt imal qualit y, brightly f luoresc -
ing, hig h-cont r a st impressions for a nalysis. The li f ting st r ips’
f luore scent pro per ties i ncr eased the se nsitivit y and contrast for
visua lization of lif t ed age d impre ssions that we re faint o r invis -
ible u nde r nor m al lig htin g condit ions . Mo st of the subs t rate s
from t he age d impression t r ial s produced ident ifiable impres -
sions on samples aged for one month when v iewe d un der normal
lighti ng conditions. Therefor e, subseque nt en hanceme nt of lif ted
impressio ns wa s not always necessa r y.
Journal of Forensic Identif ication
272 / 61 (3), 2011
(a) (b) (c) (d)
Figure 8
Aluminum (aged 1 month): (a) blood lift (ALS); (b) blood lift (normal
lighting); (c) substrate after the lift (ALS and no barrier lter); (d) substrate
after the lift (normal lighting).
(a) (b)
Figure 9
Steel sheet metal (aged 6 months): (a) blood lift (normal lighting); (b) blood
lift (ALS).
Journal of Forensic Identif ication
61 (3), 2011 \ 273
(a) (b)
Figure 10
Black leather (aged 6 months): (a) blood lift (normal lighting); (b) blood lift
(a) (b) (c)
Figure 11
Cotton fabric (aged 6 months): (a) substrate after the lift (normal lighting);
(b) blood lift (normal lighting); blood lift (ALS).
Journal of Forensic Identif ication
274 / 61 (3), 2011
Subsequent en hancement with an ALS was mar ke dly benef i-
cial for the st ained wood. Many of the l ifted im pre ssion s f rom
st aine d wo od were faint af te r on e we ek a nd by thre e months ,
th e re we r e no visibl e remnant s of blood on t he lifting st r ips
under norma l lighti ng conditio ns. W hen t he l ifts were sub se-
quently enha nce d wit h an ALS , lift ed impression s aged for on e
mont h wer e identif iable. At three and six mo nth s of agi ng, the
li f t s sti l l dis pla yed overal l imp r ession pat te r ns, bu t wit hout
specific ridge pat h det ail to support an identificat ion.
The ot h e r aged impressi on substrates (aluminum, black
plastic, metal, and cot t o n f abric) that had bee n ag ed for six
month s d i spl ayed ide ntifiable i m pres sio ns in the major it y of
th e t r ial s whe n visu a lized w ith a n A LS (Figure s 8a, 9b, 10 b,
and 11c). The ALS enhan cem ent inc reas ed t he sens itivit y and
imp r ove d the cont r a s t on lifted i m pressions th at were f a i nt
(Table s 2 a nd 3).
Age d Impre ssion s - Lif t Qual ity ( Visua lize d with an ALS )
Subs trate s 1 Hou r 1 Day 1 Wee k 1 Mon th 3 Month s 6 Mo nths
Nonp orous: Alum inum *** *** *** *** *** ***
Nonp orous: Black Plasti c *** *** *** *** *** ***
Nonp orous: Metal *** *** *** *** *** ***
Sem iporou s: Sta ined Wo od *** *** *** *** ** **
Sem iporou s: Blac k Leat her *** *** *** *** *** ***
Poro us: Cot ton *** *** *** *** *** ***
0 = no vi sible p rotein aceou s mate rial, no vis ible r idge de tail
* = visi ble prot eina ceous mater ial, no visib le ridg e deta il
** = visib le prot einac eous m ateri al, vi sible r idge d etail includ ing so me rid ge pat hs or i mpress ion pat ter n
*** = visibl e prote inace ous ma teri al, vi sible r idge de tail i nclud ing im pressi on pat tern and ri dge pat h with clear detai ls
Table 3
Lift quality: visualized with an alternate light source (ALS)
Du r i ng the se t r i als, espe cia lly during t he a ged i mpr ession
trials, as the age of t he impressio ns i ncrease d, t he more fixed
the im p r e s sio n s be c a me to the non p o r ous and som e of the
semiporous subst rates. The subs t rat e’s composit ion and por os-
it y se e med to h ave the grea t est eff ect on this pro c ess. Eac h
su bst r ate pr oduc ed co nsistent res u lts t h roug hou t the t r i als i n
the amou nt of blood that re mai ned on t he substrate after lif t ing,
wh ich notic eably i ncr ease d as t he i mpre ssion s aged. It i s the
author’s opi nion th at as the impressions age d, the b ond bet we en
th e blood y imp ress ion and t he su bst ra te inc reas ed, ma k i ng it
ha rder for the lifti ng st r ip to l ift the ent ire impressio n from the
subst r ate s. I n th e appl ication of the lifti ng strips, s ome of th e
blo od-bi nding ing redients were imparted to the bloody imp res -
sio ns left behi nd on the subst rat e. This occur rence a llowed fo r
Journal of Forensic Identif ication
61 (3), 2011 \ 275
the lifting str ip to li ft a copy of the substrate impression (Figures
8a and 8b), while also provid i ng an e n hanced substrate imp res -
sio n for a nalysis ( Figures 8c and 8d). The whitish-grey bi nding
ingredient s of the lif ting st rip often improved the cont rast of t he
subs trate impression u nde r nor mal lighting conditions (Fig u res
8d and 12 a) and als o pr ovided a f luoresc ent impr ession when
vi sualize d with an A LS ( Figure s 8 c a nd 12b). T he f luor escent
inten sity observed on the f i xe d substrate imp ression s appe are d
to be grea ter on substrat es of decreased p oro sit y. T he s u r fac e
on which the impre ssion was dep osite d d id dictat e t he f luores -
ce n t cap a bilit ies. Th e por ous sub s t r a t e impre s sion s did not
produce any obse r vable f luorescence wh en visu aliz ed wit h an
AL S. O ve rall, the occurre nce of t his aging ef fe ct on the nonpo-
rous a nd on s ome of the sem iporous sub strates broa dened the
effective ness of the li fting st r ip, e spe cially r ega rdi ng the aged
impressio ns.
Dilu tio n Trials
Wat e r- d i lut e d b loo d y i m pression s were depos ited on f ive
subst rates: two nonporous (glass and blue plast ic), two sem iporous
(b rown vinyl and gloss y pap er), a nd one porou s (cot ton fabr ic),
which were selecte d as representative samples from the substr ate
impr ession trials. The water-to-blood dilutions were 1/10, 1/100,
an d 1/100 0; und ilu ted blo od wa s use d as a c ont r ol . Ten trial s
were con duc ted for each of the four d i lut ion s and left for one
hour befo re li f t i ng f rom the f ive sub strat es for a t otal of 20 0
lifted im pre ssions. The wate r- dilute d bloody impressions were
also vis ual ized with a n ALS to vis uali ze i mpression deta ils that
were not visi ble und er nor mal lighting condit io ns.
Th e und iluted impressio ns p rod uce d op timal qu alit y lif t ed
imp r e ssio n s that displ ayed the overall im pression pa t t e r ns,
rid g e pat h s , dev i a t ions, and dimensional at t r ib utes, ha v i ng
exc ept ional clarit y a nd contras t ( Figure 13a). Li f ts f rom glass,
blue pla stic, and glossy paper produced identif iable impre ssions
th at dis played overall i mpr ession p atte r n s, r idge pat hs, dev ia-
tion s, and some dim ensio nal at t r ibutes with the 1/10 d ilu tions,
howe ver, wit h a l ighte r con t r a st (Figure 13b). T h e majorit y
of the l i f ted imp ression s f rom b row n v i nyl d isplayed overa l l
impressio n pat terns w ith s ome r idge detai ls paths w ith the 1/10
di lut ion s. Cot t on a t 1/10 and gl ass, blue pl astic, glossy pa per,
and brown vinyl at 1/10 0 d isplayed som e v isible prote inaceous
mate ria l, but with no visible ridge details (Fig u re 13c). Cotton at
1/100 and al l t he other substr ates at 1/1000 did not display any
visible proteinaceous materials (Figure 13d).
Journal of Forensic Identif ication
276 / 61 (3), 2011
The lifted imp ression s from these trials were also visuali zed
with a n ALS (Fig u res 14 a- d). Ma ny of the lif t ed i mpre ssion s
th at we r e faint or inv i sible under nor m al lig hting co ndit ion s
were effectively e n han ced with an A LS. The 1/10 dilutions were
often faint (Fig u re 13b) and were en hanced through visual iza-
tion with an A LS ( Figure 14b). T he 1/100 dilutions were often
invisible or fai nt u nder norma l lighting conditions (Figur e 13c),
but t he majo r ity of th e imp ressio ns di spl ayed ove r all i mpre s-
sio n patte r ns with some ridge paths and de viations wit h an A LS
(Figure 14c). The 1/1000 t r ials, however, d id not produc e visible
prot eina ceous mat eria ls in t he major ity of the s ubs t rat e t r ials ,
eve n w ith s ubsequent enha nce ment (Figu r es 13d and 14d).
The dilution trials effect ively demonst r ated t he lif ting strips’
abilit y to lif t di luted bloody impression s made with 1 pa r t blood
to 100 parts water. The abilit y to vi sualiz e dilute d lifted impres-
sion s with a n ALS fur ther demons t rat es th e se nsitiv ity of the
li f t i ng strip s a nd the int e nsit y of the r esult i ng f luore s cenc e.
The sen sitiv ity of the l ifting strips in these t r ial s cou ld on ly be
na r rowed t o a r ange be t wee n 1/10 0 and 1/1000. In t he f ut u re,
more d ilution trials w ill be conducted t o spe cif y t he se nsitivit y
of the l ifting strips within a na r rower r a nge.
Fluo res cen ce
The f luor esc enc e produced by the li f ting st r ips was con sis -
te nt and long last i ng. The re wer e no noticeable dif fer ences i n
f luorescent i nten sit y between lifte d im pre ssion s when vis u al-
iz ed w ith an A LS af ter an hour or a fter six month s. T hes e li fted
impressio ns were ex pos ed t o an A LS for short, but oft en repet i-
tive, pe r io ds. T he aver age exp osu re times range d from 15 to 20
mi nut e s. T he l ifted imp res sions wer e vi sual ized wit h an A LS
ma i n ly to r ate the impr ession qual it y a nd t o phot ograph the
en hanced impre ssion.
Journal of Forensic Identif ication
61 (3), 2011 \ 277
(a) (b)
Figure 12
Painted drywall: (a) substrate after the lift (normal lighting); (b) substrate
after the lift (ALS).
(a) (b) (c) (d)
Figure 13
Glossy paper (normal lighting) blood–water dilutions: (a) 0; (b) 1/10;
(c) 1/100; (d) 1/1000.
(a) (b) (c) (d)
Figure 14
Glossy paper (ALS) blood–water dilutions: (a) 0; (b) 1/10; (c) 1/100;
(d) 1/1000.
Journal of Forensic Identif ication
278 / 61 (3), 2011
Conclusion and Re comme ndations
These recently developed fluorogen ic blood-lifti ng strips have
de mon strat ed their n ear u n ive rsal effective ness in thi s stud y.
Ma ny of t he cur rent l i m itat ions that ar ise wit h t he enha nce-
ment of bloo dy i mpression ev ide nce will be avoided with t h is
new met hod. T he lif t i ng str ips provide d a si mple and nontox ic
method for lif t i ng a nd photog rahing blo ody impressions f rom
various substrates, regardless of porosit y, background color, and
patterns. T he li f t i ng s t r ips’ f luorog enic prop ert y provid ed a
highly sensitive f luoresce nce of imp ression detai ls tha t we r e
not v isible und er normal lig hting condit ion s. T h e f luoresc ent
proper t ies of the lift ing strips we re not affecte d by the substrates
on w hich the imp res sions were or igin ally d eposited, and t here
were no ca ses in which f luoresce nce was not achieved (alt hough
moisture in the lifting s trip s w ill inhibit t he f luor esc ence, and
the l ifting strips must be completely drie d f r om the ac tivati ng
solution before v isua lizat ion wit h an A L S). Th e lif t i ng s t r ips
were also unique i n the aspect that f i xe d s ubstrate i mpressions
were not a lte red o r des t royed i n the applic ation of the liftin g
st r ip and , i n many ca ses , e n hanced the f ixed su bst r ate im pre s-
sions while lifti ng a copy of t he i mpression. The wh itish- grey
f luor oge n ic bindi n g i n g r edie nts f r om t he lifting strip s were
im parte d t o fixed sub stra te i mpressions on the no npo rou s a nd
on some of t he se mip orous subst rat es, en hancing t hese imp res -
sio ns in both no r mal and alternate lighting.
The lifte d bloody i mpre ssions f rom t h ese t r i als h ave been
preser ve d w ithout any not iceable degrad ation or altera tions of
imp ress ion d etails or q u alit y for near ly two years wit h t heir
f luoroge nic prope r tie s s till viable for analysis . However, more
research i s needed to de ter mi ne whether continuous or le ngthy
exposu re times wit h an ALS may di minish f luorescent inte nsity.
Ack nowle dgm ents
I wou ld like to t h a n k Steve Pa r ke r (K a l a m a zoo Pa p e r
Chem ica ls, Kalam azoo, MI) for supplying tit a niu m dioxide for
us e in the rese arch , Den i se Robaczew ski a n d Molly McKeith
(Madon na University students) for their assistance in the dep osi-
tion of literally t housands of blood y i mpressions , the Mich iga n
St a te Polic e No r t h v ille Crime L a b fo r providing lab o r ator y
equipme nt and re sou rces, Lt. Bob May (M ich iga n Stat e Police
Latent P r int Unit Supe r vis or, Northville Crime Lab) for provid-
ing practical insight to ma ke thi s proje ct a success, Rose Jones
(M ichigan State Police DNA Tech n ician, Northville Crime Lab)
Journal of Forensic Identif ication
61 (3), 2011 \ 279
for drawing my blood we ekly without causing me to o much pain
in the pro cess, and Mike Zarate ( Michigan State Trooper a nd my
husband) for his cont inued su pport and encouragement.
For f u r t her in fo r mat ion, please contact:
Jess ic a Z arat e
Adju nct I n struc tor
Ma don n a Unive rsity
3660 0 S ch oolcr aft Ro ad
Livoni a, Michigan 4815 0
(73 4) 432-530 0
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... The effectiveness of f luorogenic enhancement chemicals is dependent, among other factors, on the substrate porosity and degree of background interference, both of which affect the overall f luorescent sensitivity and contrast for analysis [1,3,7]. Immediate photography is recommended with most f luorogenic enhancement methods [2], because f luorescence is often shortlived [1], and the impression can be altered or destroyed in the enhancement process. ...
... Zar-Pro Fluorescent Blood Lifters (Lifters) provide an easyto-use, nontoxic method for lifting, enhancing, and preserving blood impressions with long-ter m f luorescent capabilities. Impressions can be recovered from various substrates, regardless of the degree of porosity or the background patter ns pertaining to the substrate on which the impression is deposited [7]. The Lifters are also highly sensitive to proteinaceous materials, allowing for the recovery of faint or even invisible impressions that cannot be visualized under normal lighting conditions [7]. ...
... Impressions can be recovered from various substrates, regardless of the degree of porosity or the background patter ns pertaining to the substrate on which the impression is deposited [7]. The Lifters are also highly sensitive to proteinaceous materials, allowing for the recovery of faint or even invisible impressions that cannot be visualized under normal lighting conditions [7]. The f luorescent properties of the Lifters, when combined with blood and visualized under alternate lighting, create brightly f luorescing, high-contrast impressions for analysis [7][8][9]. ...
Zar-Pro Fluorescent Blood Lifters have been successful in lifting, enhancing, and preserving blood impressions; however, this technology had not been explored to determine their effectiveness in the recovery of nonblood proteinaceous impressions. This research project focused on optimizing the detection, enhancement, and preservation of impressions deposited in blood, semen, saliva, an eccrine sweat and sebaceous material mixture, and nonhuman oil using Zar-Pro Fluorescent Lifters.
... Blood holds impressions well because it is highly viscous and once dried, impressions are very stable regardless of substrate porosity. A number of studies have conducted research trials associated with the enhancement of blood impressions [6][7][8][9][10][11][12][13][14][15] but deposition variability associated with the impressions or how this variability impacted the outcomes of the studies was often not discussed. ...
... Some variables that have garnered attention are the laboratory conditions depositor, skin temperature, volume, temperature of biofluid, pre-deposition waiting time, deposition pressure angle and deposition pressure time. Studies that have controlled some of these variables have mainly been associated with the deposition of eccrine/sebaceous [1,17,[19][20][21][22] and blood impressions [7,11,13,15,23] but these guidelines should be considered essential for all fluids being used for research testing. ...
... In addition, depositor friction skin temperature can increase or decrease eccrine/sebaceous sweat production which affects not only the eccrine/sebaceous impressions but impressions deposited in all biofluids given that there is a touch component to all impressions. However few studies made reference to the donor's friction skin temperature [15,23] and its effect on the impression clarity [23]. The temperature of the biofluid has also been highlighted as a factor, specifically in the replication of blood impressions in order to mimic the fluid being secreted by a living subject [15,23]. ...
Full-text available
A number of factors can affect the quality of deposited impressions making it difficult to generate consistent reproducible impressions for analysis and can potentially affect the results of impression-based research. In order to determine the effectiveness of chemical and physical enhancement methods for testing new products, comparing existing products, or validating methods and products for implementation in forensic laboratories, impression quality must be reproducible throughout the research trials. In creating consistency the substrate and biofluid in which the impressions are made must be controlled. It is important to maintain a constant laboratory temperature, as well as controlling the parameters associated with impression deposition, such as the ratio of friction skin surface area to the volume of biofluid pre-deposition waiting time, deposition pressure, angle and deposi-tion pressure time. The ability to control for the impression deposition variables allows examiners to accurately assess enhancement methods based on optimal reproducible impressions. Variable impression quality prior to enhancement will influence the accuracy of results. Therefore deposition parameters should be standardized and adopted for each biofluid and substrate used in impression based research trials. Variations in composition and viscosity of biofluids influence the ability of a fingerprint to hold impression details. The most common and most studied biofluid found within an impression is eccrine/ sebaceous sweat. Friction skin contains eccrine pores embedded in skin, which secrete eccrine sweat; composed mainly of water with the remaining mixture containing organic and inorganic materials. In contrast sebaceous sweat is primarily composed of fatty acids, glycerides, cholesterol, squalene and lipid esters [1,2]. Environmental contaminants, such as cosmetics, hair products and tobacco use may also affect the chemical composition of deposited impressions [3]. Most fingerprints are deposited in a mixture of eccrine and sebaceous materials as sweat is constantly secreted from all types of skin pores. In fact most impressions will contain some amount of touch eccrine/ sebaceous material, even if in combination with other biofluid such as non-human oil, blood, semen and saliva. Non-human oil is the term used in this study to describe any food-based oil in which impression evidence could be deposited. Impressions deposited in oils can be transferred from food sources while eating or cooking to a variety of different substrates. The composition and viscosity of oils have the ability to create fragile yet valuable impressions that can be collected and enhanced as evidence. Some studies have analyzed oil or grease impressions in regard to determining suitable enhancement methods [4,5] but few studies have been published on this topic. Blood is another biofluid frequently encountered at the scene of violent crimes, and it is therefore likely that impression evidence may be present. Blood is composed of erythrocytes, leukocytes, platelets and plasma which contain a mixture of amino acids, proteins, salts and other compounds [6]. Blood holds impressions well because it is highly viscous and once dried, impressions are very stable regardless of substrate porosity. A number of studies have conducted research trials associated with the enhancement of blood impressions [6-15] but deposition variability associated with the impressions or how this variability impacted the outcomes of the studies was often not discussed. Semen is another biofluid commonly found in association with criminal cases. Composed of acid phosphatase, spermatozoa, citric, lactic acid, fructose and zinc [2], it is highly viscous and therefore likely to preserve impression evidence. In addition to semen, saliva is also capable of holding impression evidence. Saliva is primarily composed of water, but also contains buccal epithelial cells, amylase, lysozyme, glucose [2] and possible contaminants such as food that can cling to the inner cheek and the teeth of an individual [16]. The high concentration of water has an effect on the stability of saliva impressions making them more fragile. Despite the possibility of these impressions being present at crime scenes there have only been a limited number of research studies that include semen [10] and saliva [7,10]. While many biofluids have the ability to hold impression evidence the substrate onto which the impression is deposited strongly affects Zarate J, et al., J Forensic Leg Investig Sci Abstract In an effort to minimize human and environmental factors associated with the deposition of impression evidence researchers can utilize optimal deposition parameters to generate consistent reproducible impressions for analysis.The deposition parameters defined in this study provide a guideline for producing optimal fingerprints deposited in common biofluids (eccrine/sebaceous sweat, non-human oil, blood, semen and saliva) onto a variety of substrates encountered at crime scenes. Optimal quality impressions can be used as a control in depletion or dilution series to test the effectiveness of new products conduct chemical and physical enhancement trials as well as to validate enhancement methods for laboratory use.
... Similarly, the work by Goecker et al. [105] in 2016 also manifested that the CTF technique produced no significantly different degradation patterns compared with undeveloped fingerprints, consequently it would not hinder downstream DNA tests. The [20, [107][108][109] similar outcome was obtained by Tiedge et al. [106] in 2020 as well. Through a massively parallel sequencing and STR analysis after 100 bloody fingerprints were checked with and without CTF enhancement, they observed there was no inhibition on DNA from the evaporant materials. ...
... This technique aimed to solve the problem that ridge pattern in blood tends to be visually interfered in complex texture or multi-color background. Morden and Zarate [108] believed that the intrinsic fluorescence of the lifting strips is due to a phenomenon known as metal-enhanced fluorescence, so the principle of this technique is that blood and other protein secretions contain fluorophores that can be triggered by an alternative light source (ALS) when fixed close to certain metals. After comprehensively evaluation of this easy-to-use strip, Kemme in 2014 [109] gave positive feedback that it could produce more reliable and reproducible results and pose as an optimal enhancement method of a blood fingerprint stain over Hungarian Red on nonporous surfaces at crime scenes. ...
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The blood fingerprint enhancement is not so eye-catching as latent fingerprint development in forensic community, but it is indeed an important piece of evidence for personal identification, forensic analysis and even reconstruction of crime scenes. In over past ten years, novel reagents, advanced materials and emerging techniques have growingly participated in blood fingerprint enhancement, which not only leads to a higher level of developing sensitivity, selectivity and contrast, but also endows blood impressions with more forensic significance. This review summarizes recent advances in conventional chemical reagents targeting at heme, protein and amino acid as well as emerging enhancement techniques based on advanced materials, new equipment or methods. Some critical issues in forensic science are also discussed, including partial blood fingerprint enhancement, false positive of developing reagents, the compatibility of blood enhancement technique and DNA, fingerprint age determination, and so on. Finally, we have proposed several urgent problems to be solved and the prospects of some promising techniques were proposed in the field of blood fingerprint enhancement in future work.
... Zarate and Morden describe the use of the application of the recently-developed Zar-Pro fluorogenic lifting strips for lifting, enhancing and preserving bloody impression evidence (44). The Zar-Pro strips are manufactured in sheets and cut to size according to use. ...
... Slight enhancement was observed on black cotton, however, in most instances the enhancement was poor or non-existent as was observed for impressions on denim and leather. Background staining Health effects Diffusion Amino Acid Staining Easy to apply Suitable on patterned background Very expensive solvents Not suitable on black fabrics Requires wet/dry oven Alginates Good results on all fabrics Post processing of alginate Expensive Cumbersome Not suitable for sequential enhancement Although a recently new, novel fluorogenic method for lifting, enhancing and preserving impressions in blood produced excellent enhancement results on various substrates, including fabric, the cost of such lifts is prohibitive for many laboratories [49]. The use of acid yellow 7 is a cheap, readily available and an easy technique to apply on dark fabrics where immersion or spraying methods may be used. ...
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The use of chemical enhancement techniques on porous substrates, such as fabrics, poses several challenges predominantly due to the occurrence of background staining and diffusion as well as visualization difficulties. A range of readily available chemical and lighting techniques were utilized to enhance footwear impressions made in blood, soil, and urine on dark and patterned fabrics. Footwear impressions were all prepared at a set force using a specifically built footwear rig. In most cases, results demonstrated that fluorescent chemical techniques were required for visualization as nonfluorescent techniques provided little or no contrast with the background. Occasionally, this contrast was improved by oblique lighting. Successful results were obtained for the enhancement of footwear impressions in blood; however, the enhancement of footwear impressions in urine and soil on dark and patterned fabrics was much more limited. The results demonstrate that visualization and fluorescent enhancement on porous substrates such as fabrics is possible.
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This represents one of several sections of "A Bibliography Related to Crime Scene Interpretation with Emphases in Geotaphonomic and Forensic Archaeological Field Techniques, Nineteenth Edition" (The complete bibliography is also included at This is the most recent edition of a bibliography containing resources for multiple areas of crime scene, and particularly outdoor crime scene, investigations. It replaces the prior edition and contains approximately 10,000 additional citations. As an ongoing project, additional references, as encountered, will be added to future editions. From an archaeological perspective, numerous resources regarding the retrieval of blood and other types of trace evidence from historic and prehistoric contexts are included in this category. The compiler wishes to reinforce that evidence exposed to the elements, or deposited years prior to discovery may retain significant information capable of impacting the interpretation of a crime scene. Both here and in the sections of DNA Evidence and Stable Isotope Analyses, several citations may be found which should demonstrate for the crime scene investigator that assumptions should never be made that blood and body fluid evidence is completely obliterated from older scenes. Loy and Wood, (1989), is an early example of how blood evidence remained viable over thousands of years. That approximately 9000 year old evidence from Cayonu Tepesi in Turkey was initially realized using one of the most basic presumptive test for blood in most crime scene technicians' tool boxes - Hemastix. Again, the section on DNA Evidence contains numerous citations expounding on work such as Loy and Wood. Analyses of prehistoric trace evidence is now common in archaeological and forensic literature. A large part of this section deals with the reconstruction of violent crime scenes based on the shape, size, and position of blood spatter, or blood stain, evidence. Primarily considered at indoor crime scenes, the same type of reconstruction could apply to outdoor scenes but becomes more difficult given the effects of weather, and substrate movement. Works such as those of MacDonnell, (1997); Bevel and Gardner, (2001); and James, Kish, and Sutton, (2003), have served to expose criminal investigators to the stories represented in patterns of what would appear to most of us as bloody Rorshak tests. Those same works and others included in this section should also demonstrate the pitfalls of interpreting blood stain evidence without adequate training, experience, and certification. Probably the the most cross-referenced citations in this section have to do with DNA research; however, the researcher is also directed to sections on Photography, Fingerprint, Ear Print, Lip Print, and Tattoo Evidence, Firearms and Toolmark Evidence, Shoe and Tire Impression Evidence, and General Crime Scene and Death Scene Investigation Topics, for techniques in recording blood pattern evidence and bloody transfers in form of patent and latent prints involving body and clothing segments.
A survey was conducted on the possible transfer of bloody fingerprints revealed or enhanced by leucocrystal violet (LCV), leucomalachite green (LMG), and diaminobenzidine (DAB), and to set up a unique transfer mode.
Titanium dioxide (TiO2), a common paint pigment, can be used to develop latent prints from a variety of surfaces, including adhesives. It can produce an especially useful contrast on dark or transparent tapes, particularly electrical and duct tape. TiO2, in a mixture of Kodak Photo-Flo 200 and water, works as a white small particle reagent (SPR-W) and can recover usable prints by direct application to the surface. Both the adhesive and nonadhesive sides of tape can yield viable results when correctly treated. The white titanium dioxide particles that are present in the reagent adhere to the oily component in fingerprint secretions, allowing an identifiable contrast between ridge detail and the substrate background [1].
This study investigated a selection of methods to detect latent fingermarks on black electrical tapes. Subsequently, a sequence of techniques was developed and is suggested as a standard operating procedure. Different formulations of white and silver powder suspensions were developed by comparing Citron detergent and Kodak Photo-Flo as the surfactant in the suspension. A mixture of both surfactants in the suspensions repeatedly produced greater fingerprint development on the adhesive side compared to using either one on its own. Two techniques consistently performed to a higher standard for both fresh and aged marks on the adhesive side: cyanoacrylate followed by a combined basic yellow 40/basic red 28 stain and the white powder suspension. The contrast, sharpness, ridge detail, and simplicity of preparation and application achieved with both of these techniques made them superior to the other methods tested. The sequence that proved successful on the adhesive side of all tapes tested involved cyanoacrylate fuming and application of a fluorescent stain, followed by white powder suspension, and finally gentian violet with a transfer of developed marks if necessary. This sequence allowed maximum development and the greatest enhancement of latent marks, without causing the destruction of the deposit for subsequent methods. Latent fingermarks on the backing (nonadhesive side) of the electrical tape were also successfully developed with cyanoacrylate and the fluorescent stain, so treatment of the backing could be incorporated into the sequence.
To date, no experiments have been published measuring the cause and effect relationship of various deposition factors and the resultant appearance of the ridge detail in a bloody friction ridge impression. This study reports the effects of deposition pressure (at four categories of pressure: light, medium, heavy, and extreme), the effects of increasing volumes of human blood loaded onto a finger (from 10 µL to 100 µL), the effects of depositing impressions on a horizontal surface versus a vertical surface, and finally, the effects of allowing the blood to dry on the finger for a significant amount of time before depositing the impression (hereafter: predeposition wait-ing interval or PWI). Prior to testing these variables, a series of study design tests were also performed to optimize the conditions of the study. During these tests, we examined several other factors (such as the temperature of the blood, the ambient air temperature, the tem-perature of the skin) for their contribution to the appearance of the bloody impressions. The trials showed that to produce identifiable impressions, rel-atively small amounts of blood were needed (10 to 20 µL). When impressions were deposited in a vertical position, increasing the deposition pressure produced more impressions of evidential value. Identifiable impressions were produced with larger volumes of blood when there was a significant PWI interval. After allowing some of the excess blood to dry on the finger, an identifiable impression was deposited.
The objective of this research project was to demonstrate a quick and easy method for impregnating nylon transfer membranes with leucocrystal violet (LCV) for the purpose of lifting and enhancing impressions made in blood. A stamp that would simulate fine detail found in fingerprints or footwear was used to create impressions on a variety of substrates. Four different LCV formulations were tested to determine the effectiveness of the prepared membranes in lifting and enhancing the impressions. Further investigation involved the feasibility of using the LCV membranes in the field by studying the shelf life and storage of the impregnated membranes and the longevity of the lifted impressions. One of the formulations studied demonstrated superior lifting and enhancing capabilities, as well as a prolonged shelf life and a resilience of the lifted impressions, thus proving LCV to be an extremely valuable technique.
A simple, quick, one-step method for the recovery and enhancement of blood-contaminated shoe marks, incorporating the widely used leuco malachite green, has proven very successful in laboratory trials. The method uses nylon membranes as the lifting media which have previously been impregnated with leuco malachite green. The membranes are activated with deionised water and placed on the marks producing an excellent lift and enhancement simultaneously from a variety of different substrates. The method should prove extremely useful at crime scenes.
Amido black (acid black 1) is the dye currently recommended by the UK police service for the enhancement of blood-contaminated fingerprints. Acid black 1 is a general protein stain and can be used for enhancing fingerprints in blood in either a methanol or water-based formulation to produce blue-black fingerprints. As both the water and methanol-based formulations have problems associated with their use, a program of research has been carded out to examine alternative formulations of the dye to find the most effective method for the enhancement of fingerprints in blood. After carrying out systematic evaluation on a range of typical surfaces, an alternative solvent system for amido black has been developed.
The rutile forms of titanium dioxide work very well for developing latent prints on dark surfaces. When used as a substitute for Sticky-side powder, they produce excellent results on black electrical tape and have the added advantage of developing prints on both sides of the tape. They also work well on plastic bags and cellophane. Titanium dioxide powder can be used as a white fingerprint powder or may be mixed with water and Kodak Photo-Flo to make a white small particle reagent.
It is the responsibility of the forensic specialist to have knowledge of available resources and be able to use these resources to detect, collect and preserve physical evidence during an investigation. The objective of this article is to make members of the forensic law enforcement discipline aware of some of the procedures available to them to enhance blood prints found at a scene or on an exhibit. The Royal Canadian Mounted Police (RCMP) presently uses six bloodstain enhancement techniques: Amido Black, Crowle's Double Stain, Hungarian Red, Leucomalachite Green, Luminol, and forensic light sources. For the purpose of this experiment only the first four mentioned were used. Luminol and the forensic light sources will be discussed in the conclusion of this report.RÉSUMÉLors d'une enquête, le spécialiste médico-légal se doit de connaître les ressources disponibles pour la détection, le prélèvement et la conservation des différentes preuves physiques. Le but de cet article est d'informer la communauté médico- légale des différentes techniques disponibles pour améliorer la détection d'empreintes faites de sang observées sur une scène de crime ou sur un objet. La Gendarmerie Royale du Canada (GRC) utilise six méthodes pour améliorer la visualisation des taches de sang: Amido Black, Double coloration de Crowle, Hungarian Red, Leucomalachite Green, Luminol et différentes sources lumineuses. Lors de cette expérience, seulement les quatre premiers produits ont été utilisés. Le Luminol et les différentes sources lumineuses seront discutés dans la conclusion de cette communication.