mccrone_ microscopia

8/3/2019 McCrone_ microscopia

1/7


2/7

78 Acc. Chem . Res., Vol. 23, No. 3, 1990 McCroneTable IEnergy Disper sive X-ray Analysis (EDXRA ) of Blood-Image-Area She rds

particle diam etef color Na Mg A1 Si P Hg/S C1 K Ca Fepeak heights*

ABCGHIJKLMN

129231292311115119

orangeredred-orangered-orangered-orangeorangeyellowredorangenonered-orange

721


3/7

The Shroud of Turin. Blood or Artist's Pigment?

2 3

Acc. Chem. Res., Vol. 23, N o. 3, 1990 79

4

5 6 7

9>

0Figure 2. Yellow body-image area on the Shroud; photomacrograph by Mark Evans, 9X.Figure 3. Red blood-image area from small of back; photomacrograph by Mark Evans, 2 2 ~ .Figure 4. A yellow linen fiber from tape 6-AF, 220X.Figure 5. Image particles on Shroud tape 3-CB, 55X.Figure 6. Red particles on a Shroud linen fiber, 3-CB, 1650X.Figure 7. Modern red ochre pigment particles, 1650X.Figure 8. A blood-area red pigment aggregate, 220X.Figure 9. Vermilion in a single Shroud particle aggregate from tape 3-CB, 220X.Figure 10. A group of microchemical tests for mercury (mirror formation by precipitation from HgS solution by metallic copper).The arrow indicates the test result for a Shroud particle aggregate from tape 3-CB, 16X.pigment. Less tha n one-half of the pigm ent is crys- are synthetic mercuric sulfides, one a mod ern wet-talline ( hem atite or vermilion), hence th e lines in the process product, an d th e othe r, a dry-process form firstXRD attern are very spo tty and difficult to measure. prepare d by alchemists abo ut 800 A.D. All th re e areThe agreement with known hematite dat a is, nonethe- readily distinguished microscopically. Significantly, theless, convincing. vermilion on the Shrou d is the 800 A.D. form.Microscopical Identification of Vermilion

Th e blood-image areas show incrustations of a redsubstance with indications of "spalling" (Figures 3 and8). Many loose particle aggregates, picked from theblood-image tapes, show red particles different in shapeand color from red ochre ( Figure 9), but characteristicof the artist's pigment, vermilion (HgS). Artists haveused a t least thre e microscopically differen t vermilionpigments, all with the same crystal structur e as themineral cinnabar. Th e most common vermilion pig-men t is the grou nd mineral cinnabar. Th e other two

Th e chemical composition of this second red p igmentwas established by polarized light microscopy (PL M ),by electron microprobe: by XR D (Tab le 11),and mi-crochemically (Figure 10). Th e PLM microchemicaltest requires wet ashing of one of the blood-imagesherds to remove the o rganic binder, dissolution of th eHgS crystals in H I0 3, and p recipitation of a merc urymirror with m etallic copper. All of this is done in a4 0 0 m diameter droplet on a copper penny (Figure10)asa source for copper. Many tiny simulated knownvermilion blood she rds were tested on th e same penn yto develop this procedure, which was then used to test


4/7

80 Acc. Chem. Res., V ol.23,No. 3, 1990 McCrone

Figure 11. A 3-CB lood-image-area sherd: (a) back-scattered electron image (upper le ft); (b) an ron map (upper right); (c) a m ercurymap (lowe r left); (d) a sulfur map (lower right), 3000X.one of th e Turin Shrou d sherds (arrow in Figure 10).The same XRD patte rn identified hem atite in thisblood-image sherd (Table 11) and also showed thestronge st lines for cinnabar, confirming vermilion. Anumber of these blood-image she rds were analyzed byelectron microprobe4 (Ta ble I). Figure 11 shows aback-scattered electron image of one sherd and thecorresponding Fe, Hg, and S elemental maps. Th e factth at these map s show discrete volumes for these ele-ments, and Table I shows varying ratios for the twodifferent pigments, proves there mus t have been twodifferent pain t applications, one a red ochre pa int, andth e other, a vermilion paint. Th e different paint sherdsshow varying amounts f red ochre relative to vermilion;this also supports the app lication of two paints. Fur-thermore, no vermilion pigm ent particles were observedon any of thousa nds of body-image tape fibers. It seemsreasonable th at th e Shrou d was first painted with a redochre paint an d the n th e blood images were enhancedwith a vermilion paint.The finding of HgS as an artist's pigment on theShroud is highly significant. One migh t argue th atFe 20 3 ould be formed from blood, bu t it is not possibleto explain HgS a s vermilion except a s an artist's pig-ment. Th e energy dispersive spectru m in Figure 12an dsimilar spe ctra for 10 other blood-image sherds weremeasured to give the quantitative elemental composi-tions tabulated in Table I.Microscopical Identification of Collagen

If the image on the Sh roud is a painting, we must finda paint medium. Because th e image is so faint, thepain t layer will be almost invisibly thin in m ost areas.However, I did find evidence of a m edium a s a driedfilm, or other accumulations, on t he Shro ud linen fibers.On one ta pe (1-AB) I observed two fibers "cemented"together with a yellowed residue. Fu rthe r exam inationby PLM t 2W400X shows paint residues on a nu mbe rof fibers (Figure 13)and very thin paint layers strippedfrom th e fiber surfaces by t he tape lifts (Figure 14).Therefore, I decided to test t he image fibers for paintmedia (drying oils, gums, tempera) and blood usingmicrohistological stainin g reactions. A bromcresol pe entes t for drying oils was negative, as was an orcein testfor gums. However, tests for protein, using am ido blackas well as uchsin, show thin stained paint residues, and

................. . . . . .. . .................. .. .. . . . .. I ..- -__._____. . . . ., . .. . . . . -* -.st :..................... .: : :+

i :, : ; :; ; ;:I:,. . . . . . . . . ..-_.._.__._.. . . . . . .. . . . . . . . .. . . . . . . .. . . . . . . . . . . . . ........ .. . . .. . . . . .. . . . ........ . .. . .. . . . . .. . . . ._--*.. . .. . . .* . .. . ........ . . . .. . . .

............ . .. . . .. . . . . .. . . . . . ............. . .. . . . . . . . .. . . . . . .-.-...-.... . . .. . . . . . .. . . . . .. . . . . . . . . ............. . . .. . . . . . . . .

.... . -..... . . . . . .. . . . . .. . . . . . .. . . . . . . .............. . . .. . . . .. . . . . . .. . . . .............. . .. . . . . . . . .. . . . . . .. . . . . .............. . . . . . .. . . . . . . . . . . . .. . . .

. . . . . . . . . . . .. . . . . . . . . . . ..-...-...... ..................... . . . . . . . . . . . . . . . . . i....................... . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . .- ............ . . . . . . .. ,- . . . . . . .. . . . . . . . . .. . . I . . . . . . . .............

...................................................................................... '. . . . . . . . . . . . . . . . . . #. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. L ...............Figure 12. Energy dispersive spectrum or a single blood-imag esherd showing both Hg and S characteristicof vermilion and F echaracteristic of red ochre.occasional accumulations of pai nt (Figure 15) on theimage-area fibers from several tape s including 1-AB,3-CB, an d 6-AF. In ma ny of these accumulations, redpigment particle s are observed. Figure 16 shows oneblood-area sherd from tape 3- CB t he collagen is stainedblue with amido black, and a hint of red pigment isapp aren t within the sherd.Before continuing with furth er tests, I prepared twopain ts in order to produce Shroud-like images: a 3%aqueous blood solution, and a collagen tempera pre-pared from gelatin? Th e tempera paint was preparedwith 10ppm red ochre in a 1% aqueous gelatin solution.A noted Chicago artist, the late Walter Sanford, paintedShroud-like images with both pain ts; tran spar ent (ad-hesive) tape s of th ese images were compared with th eShroud tapes. I also applied dro ps of each pa int, onea t a time with drying between each drop, to linen stripsto observe the sp ot color and sha pe (Figure 18). Eachdro p contains known amoun ts of iron in th e form of redochre or blood. Th e blood-image spots are m ade up 1,2,3, .... 10 drops/spot. Th e red ochre/tempera spotsare made with 5, 10, 15, .... 80 drops/spot. A glanceshows th at i t would be impossible to pain t the T urinShrou d with diluted blood beca use of the brown color

(6) McCrone, W. Wiener Berichte uber Naturwissenschaft in derKunst 1987/1988,4/5,50.


5/7

The Shroud of Turin: Blood or Artists Pigment? Acc. Chem. Res., Vol.23, N o. 3, 1990 81

14

Figure 13.Figure 14.Figure 15.Figure 16Figure 17Figure 18Figure 19Figure 20.11oox.

18

1

19 20 21A Shroud linen fiber showing a paint residue with encapsulated red ochre pigment particles, 220X.A thin paint film stripped from blood-image fiber by the tape and with dispersed red ochre particles, 66X.A dried paint residue on a 1-ABShroud linen fiber stained with a protein stain, amido black, 220X.A Shroud 3-CB amido black stained blood-image sherd, 220X.A real-blood particle catalytically decomposing NaN3 in solution to give N2 bubbles, 66X.Each succeeding spot has an increasing number of drops of paint.Blood-coated linen fibers from a modern shroud painted with a diluted-blood paint,660X.1 ed ochre paint-coated linen fiber. The red ochrewasmodern commercial pigment, and the medium was collagen (gelatin),A linen fiber from the Turin Shroud (arrow) and two real-blood-coated linen fibers and blood particles in NaN3 solutionigure 21.showing N2 bubbles around the blood, but none around the Turin Shroud fiber, 66X.

and halo shape of the spots. Th e red ochre spots, onthe other hand, match both th e shape and color of theShroud image.The tapes of Sanfords two paintings, one withblood-painted images and one with red ochre images,yielded coated fibers (Figures 19 and 20). The paint


6/7

82 Acc. Ch em. Res., Vol. 23, N o. 3, 1990prepared from a modern red ochre produces coatedfibers indistinguishable from T urin Shroud tap e fibersin color and particle dispersion. They also tes t positivefor protein with amido black in the same way. Th ediluted-blood-p ainted images, when ta ped , are verydifferent from Tu rin S hroud image tapes (Figure 19).The brownish gelatinous blood coating on the linenfibers of Sanford s blood-painted s hroud shows no redparticles an d a low refractive inde x of only abo ut 1.55.I also tested the T uri n Shroud blood-image-area tapesfrom the right-side lance wound for blood. I obtainednegative results with all forensic blood tests tried.Thes e included Takiya ma , Teichman , and benzidine aswell as H 2S 04 r eatm en t followed by UV fluorescence.These tests are positive for fibers from Sanfordsblood-painted shroud , bu t negative for Turin Shroudfibers and Sh roud blood-image sherds. One might arguetha t first century blood, or even 14th century blood,would behave differently, yet similar tests on Pers ianburial silks and Egy ptian mum my wrappings show nodifference from my year-old blood spots.Amido black is a stain for any proteinaceous sub-stance; hence I could only conclude that the paintmedium was blood, or a tempera produced during theMiddle Ages from egg, cheese, or collagen, the latte roften from parchme nt (collagen) scraps. However, ifthe Shroud paint medium is collagen, it would show oneunique difference from egg or cheese tempe ra, an d fromblood. Collagen lacks cystine and cysteine, two sul-fur-containing amino acids present in other proteins(including blood). A standard P LM test for sulfur-containing substances in particle form is the catalyticdecom position of Na N3 in solution to yield a fro th ofN2 bubble^. Figure 17 shows such a reaction betweenNaN 3 an d a particle of dried (real) blood. Collagentem pera shows no evolution of N2 in a NaN, solution;blood, egg, and cheese tempera evolve N2 from NaN,.T he tes t based on catalytic decomposition of NaN,- 2 by sulfides an d disulfides5 was the n applied toknown Sanford-painting blood-image particles and toa T urin Shroud fiber. I mounted two linen fibers, andtwo blood sherds taped from Sanfords real-bloodshro ud, shown on the right side of Figure 21 , and onelinen blood-image fiber from the Turin Shroud, on theleft. Bubbles of N2from th e surrounding N aN3 solutionare a pp are nt on the real-blood-image particles a nd fi-bers, but none around the long Turin S hroud fiber. T hepaint m edium on th e Shro ud forms no N2 bubbles withN a N , hence it does not contain sulfur-containing aminoacids. Because tha t medium is known to be proteina-ceous by histological sta inin g, it m us t be collagen.Painting of the Shroud ImageThes e results suggest tha t a talented artist carefullystudied th e New Te stam ent, sources of information onthe crucifixion, and othe r artists paintings of Christ.He then thought about a shroud image in terms of adark tomb. Inste ad of the usual po rtra it with normallight and shadow, he assumed th at the image could onlybe produced by body contact with the cloth. Hepainted directly on the cloth to image the body-contactpoints (forehead, bridge of the nose, cheekbones,mustache, beard, etc., over the entire body, front, andback). Th is automatically creates a negative image;areas that normally catch available light and appearbright, like the bridge of the nose, would instead all be

McCronedark . However, those dark areas appear brigh t on aphotographic negative. He decorated the body withblood stains as required by t he New Testa me nt de-scriptions. These he rendered dark on the Shroud,hence they form a photographic positive image super-imposed on the otherwise negative S hrou d body image.The Shroud art ist used a style of painting andpainting materials common in Europ e during the 14thcentury. A chapter e ntitled Prac tice of PaintingGenerally During the F ourteenth Century in an 1847book7 by S ir Charles Locke Eastlak e en titled Methodsand Materia ls of Paint ing of th e Great Schools andMas ters covers precisely th e Shroud -like images. Herefers to the process as th e English or German modeof painting faint images (grisaille,a light monochromeimage). As Eastlak e writes: ...After this linen ispainted, its thinness is no more obscured than if it hadnot been painted at all, as the colours have no body.The peculiarity of the English method app ears to havebeen its absolute transparency. A manuscript of thetime contains directions for the prep aratio n of trans -parent colours for painting on cloth. Eas tlake con-tinues: Th e Anglo-German method app ears, from thedescription, to have been in all respects like m odernwater-colour painting-except th at fine cloth, dulyprepared, was used instead of paper.The Opposition

Th e October 1988 results of the carbon d ating of theShroud by the Universities of Arizona, Oxford, andZurich Technological Institute8 with a da te of 1325 f65 years have not lessened opposition t o the pain tinghypothesis by many Shroud believers. Some S TU R Pauthors adm it that the Shroud has protein, F e203, ndHgS in image areas, but attrib ute th e protein to blood,the iron oxide to retting of th e flax to form linen fibers,and the vermilion to contact of the Shroud w ith paintedreplicas (to transfer the divine powers of th e Sh rou d).Many m embers of S TU RP , and others convinced of theauth enticity of th e Shro ud, explain away the c arbon-dating result by invoking impure linen samples or achange in th e date induced by th e resurrection, or bysaying tha t the dating was not a tes t of the Shroud, butthe Shroud (known to be first century) was a tes t ofcarbon dating.Th e ST UR P scientists find no pigment particles a t20-50X (I used 400-25OOX). Th ey find no cem entationof th e fiber s nor evidence of capillary flow. I observemany visual evidences of a paint medium. The y are notmicroscopists and, particularly, not microscopiststraine d in the study of pigments and paintings. The yare not familiar with the microscopical appearance andbehavior of tiny samples, in this case, both very thincollagen paint medium and sm all amoun ts of very tinyparticles in watercolor images. There is no way, a t 50X,tha t anyone could recognize the red particles as F ea 03and as red ochre or the H gS as a ninth century ver-milion, and no way anyone could see th at th e pigmentparticles are cemented into an organic matrix (paint(7 ) Eastlake, C. L. Methods and Mater ials of Paint ing of the GreatSchools and Musters; Chapter V (1847);reprinted by Dover: New York,1960.(8) Damon, P. E.; Donahue, D. J.; Gore, B. H.; Hathaway, A. L.; jull,A. J. T.; Linick, T . W.; Sercel, P. J.; Toolin, L. J.; Bronk, C. R.; Hall, E.T.; Hedges, R. E. M.; Housley, R.; Law, I. A.; Perry, C.; Bonani, G.;Trumbore, S.; Woelfli, W.; Ambers, J. C.; Bowman, S. G. E.; Leese, M.N. ; Tite , M. S. Nature 1989, 337, 611.


7/7

Acc. Chem. Res. 1990,23, 83-89 83medium), and to th e fibers. A t 400-2500X, I readilyobserve these features.Th e amoun ts of pigments and medium on the body-image areas an d some of the blood-image areas, barelyvisible microscopically, demonstrate that absorptionspectroscopy on 1-cm2 areas by Pellicorig an d o therscould not have detected them.The results published by STURP authors in moretha n 30 papers are con sistent with the sensitivity of theinstrumen ts and techniques they used. Rogers andSchwalbe summarize the ST UR P findings. Theirgrossly dispar ate conclusions read in part as follows:The primary conclusion is tha t the image does notreside in an applied pigment. Th e reflectance,fluorescence and chem ical characteristics of th e Shro udimage indicate rather than the image-recording mech-anism involved some cellulose oxidation/deh ydrationprocess.There are very small amounts of pigment an d me-dium on t he bo dy-image fibers, unde tectable excep t bycareful light microscopy a t a minimum magnificationof 400X. T h e blood-image area s hold more solid ma-terial as red ochre, vermilion, and collagen tempera but,still, much less th an a normal painting. Heller andAdlerO acknow ledge the existence of Fe 203 nd H gS inblood-image areas. Pellicorig found high conce ntrationsof iron in blood-image areas, bu t he attribu ted this toblood. However, Accetta and BaumgartlO sta te th atShroud blood comparisons with known bloodstainsshow mark ed differences. As I stand accused ofmisinterpreting [my] otherwise good data , I see that ,a t least, I am n ot alone.

(9) Pellicori, S. F. A p p l . Opt . 1980, 19, 1913.(10) Heller, J. H.; Adler, A. D. J.-Can. SOC. orensic Sci. 1981, 14,(11) Accetta, J. S.; Baumgart, . S. A p p l . O p t . 1980, 19 , 1921.81 .

ConclusionSensitive mass spectrometric m ethods have revolu-tionized carbon-14 dating in the last decade, so t ha thigh accuracy can be achieved on 1-mg samples. Th ethree independent measurements recently reported*(October 1988) show tha t the Shroud of Tu rin da tesfrom 1325f 5 years. Th is is in gratifying sup por t ofour evidence tha t an artists image is contemporary totha t time and was probably painted just before its first

exhib ition in 1356. T his conclusion, in 1980; was basedsolely on observations made with a polarized lightmicroscope, though confirmed later by X-ray, electrondiffraction, an d electron m icroprobe ana lyse^.^Very few chemistry students, undergraduate orgraduate, have ever looked through a m icroscope except,perhap s, in high school biology. T he direct micro-scopical approach to the solution of ch emical problemshas been largely lost during the past three decades.This project on the authenticity of the S hroud of Turinhas been an excellent opportunity to gain wide publicityfor the uniqu e capab ilities of polarized light microscopy,providing a real impetus to its deserved renascence.I acknowledge with grati tude the he lp of Ra y Rogers of LosAlamos, who took the excel lent Tur in Shroud tapes; Chris t ineSkir ius , one of m y s tudents , who patient ly m ade t he meticulouscolor evaluation o f more th an 8000 linen fibers; McCrone A s-sociates microscopists, including Anna Teetsov, Mark Ande rsen,Ralp h Hinch, Howard Humecki , Be t ty Majewski , and DeborahPiper , who made careful X -ra y a nd electron optical s tudies ofindividual fibers and image components; and m y wife, Lucy , whohelped t o confirm and interpret m y observations as well asmaking imp ortant suggestions for presenting the written reports.I a m also grateful to al l of t he reviewers o f this paper f or theirconstructive suggestions.Registry No. Red ochre, 37338-85-5; vermilion, 1344-48-5.

mccrone_ microscopia

Documents