assessment of cleaning effectiveness for new ecological systems on ancient tempera icon by...

Assessment of Cleaning Effectiveness for New EcologicalSystems on Ancient Tempera Icon by ComplementaryMicroscopy TechniquesSILVEA PRUTEANU,1 VIORICA VASILACHE,1 IRINA CRINA ANCA SANDU,2 ANA-MARIA BUDU,1 AND

ION SANDU1*1Alexandru Ioan Cuza University of Iasi, ARHEOINVEST Interdisciplinary Platform, Laboratory of Scientific Investigation andConservation of Cultural Heritage, Blvd Carol I no. 22, 700506, Iasi, Romania2Universidade de �Evora, Laboratorio HERCULES, Pal�acio do Vimioso, Largo Marques de Marialva, 8, 7000-809, �Evora,Portugal

KEY WORDS ecological systems; cleaning tests; juices and infusion; reflectography; colorime-try; SEM-EDX; micro-FTIR

The study presents an old icon painted in egg tempera on lime wood, with a poor conservationcondition and clogged dirt deposits. The icon is attributed to an anonymous painter of XIXth cen-tury and to the neo-classical style of painting. The painting layer was done with only a hand fullof pigments, earth colors that were often used in painting the icons from XVIIth to XIXth centuryin Eastern Europe, that have Byzantine influences. Taking into consideration the nature andthe structure of the materials from the upper layers of the painting, affected by deposits of dirtover time, a series of cleaning recipes were studied, using the so called cleaning tests with com-patible mixtures of different juices and infusion from indigenes plants, that were freshly doneand odorless. A low alkaline 95% ethyl alcohol solution, combined with a few drops of ammoniac25%, was used as a reference system, due to its compatibility with the greasy deposits found onthe polychrome layer and on the wood. The cleaning capacity of the new systems used, in com-parison with the standard solution, was analyzed through modern analytical methods of evaluat-ing the degree of cleaning, more exactly by means of visible and UV reflectography, CIE L*a*b*colorimetry by reflection assisted by SEM-EDX and IR spectroscopy. Microsc. Res. Tech. 00:000–000, 2014. VC 2014 Wiley Periodicals, Inc.

INTRODUCTION

The wood was and remains one of the most usedmaterial in making artworks, either as natural wood,when was speculated the use of its design, color, and tex-ture, either as a support for decorative elements, frames,sculptures (decorated by leafing, cladding, and poly-chrome layers) and water, oil or acrylic paintings or as anatural element (furniture, engraving, intarsia, veneers,windows etc.) (Sandu et al., 2001a, 2001b; 2002; 2003;2010a). When used as a support for gilded and poly-chrome decorations, it requires specific preparations, inthe form of a layer of ground, of different thickness.Being a perishable material, constantly submitted tobiological attack, it requires treatments to stop the dete-rioration and degradation effects, from the time it isused to create the artwork and even afterwards, whenthe conservation state demands it (Sandu et al., 2000,2001a; 2001b; 2001c; Sandu, 2008; Sandu et al., 2012).

Meanwhile, the gilding and the polychrome layerare affected by dirt that transforms from simple dust,without adherence (easily removed by whapping, suc-tion or blowing it away) into clogged dirt deposits,when the dirt, usually fat, begins to clog by means ofoxidation or thermal cornification, followed by mono-lithization, by interacting with the varnish and thepainting layer. Removing this kind of clogged dirt is a

difficult problem for restorers, because this dirt hasstrong interactions with the varnish and the poly-chrome layer, interactions that are determined by itspenetration capabilities and the porosity of the layers.The operations for removing the clogged dirt can affectthe old aged patina, the varnish and the thin layer ofcolor that are slightly degraded (Brandi, 1977; Dom-ingues et al., 2013; Mills and White, 1994). The tough-est degree of complexity is cleaning the darkenedpaintings and those that have the polychrome layerclogged with dirt (Bonini et al., 2007; Burnstock andWhite, 1990; Carretti and Mascherelli, 2004; Kuckovaet al., 2013a, 2013b; Hrdlickova Kuckova et al., 2014;Michalski, 1990; Pereira et al., 2013a, 2013b; Phenixand Sutherland, 2001; Sandu et al., 2002; Sandu,2008; Sandu et al., 2010b). These kind of cases areraising problems for the restorers, especially problemsregarding the choice of the best cleaning recipes. Thenature of the materials used to create the artwork, the

*Correspondence to: Ion Sandu; Alexandru Ioan Cuza University of Iasi,ARHEOINVEST Interdisciplinary Platform, Laboratory of Scientific Investiga-tion and Conservation of Cultural Heritage, Blvd Carol I no. 22, 700506, Iasi,Romania. E-mail: [email protected]

Received 17 July 2014; accepted in revised form 5 September 2014REVIEW EDITOR: Prof. Alberto Diaspro

DOI 10.1002/jemt.22437Published online 00 Month 2014 in Wiley Online Library (wileyonlinelibrary.com).

VVC 2014 WILEY PERIODICALS, INC.

MICROSCOPY RESEARCH AND TECHNIQUE 00:00–00 (2014)

technique, the age and also the nature, the morphologyand the structure of the deposits will always be takeninto consideration at this point (Magrini et al., 2013;Pouli and Emmony, 2000; Pruteanu et al., 2013a;2013b; Sandu et al., 2000).

Nowadays, the range of systems used in cleaningoperations is very wide, starting with those based onwater or on organic solvents (Bonini et al., 2007; Michal-ski, 1990; Phenix and Sutherland, 2001; Ruhemann,1968), with or without surfaces additives (Burnstockand White, 1990), hydro gels (Carretti and Mascherelli,2004), ionic liquids (Bonini et al., 2007; Branco et al.,2011; Pacheco, 2010; Park and Kazlauskas, 2003;Pereira et al., 2013a, 2013b; Wolbers, 2003), or enzymes(Calvo, 2002; Khandekar, 2000; Teixeira, 2011). Some ofthe organic solvents are extremely toxic for the restorerand difficult to control during their action.

Some labs use a different modern process, whichconsist in volatilization of the dirt by laser beam pyrol-ysis. This technique, though, if used wrong, destroysthe varnish and the painting layers (Oujja et al., 2013;Pouli and Emmony, 2000; Pouli et al., 2003, 2012;Siano et al., 2012; Vounisiou et al., 2010).

Over the last years, to the study of ecological, non-invasive cleaning systems was paid an increasedattention. An important part is that of the water dis-persions, made of uncolored juices, freshly obtainedfrom vegetables or green plants and infusions that con-tain tension-active chemical components with emol-lient action (saponins, uncolored tannins, furfural,poorly colored carotenoids—lutein, and zeaxanthin;

enzymes, glycosides, alkaloids etc.). These have,besides the emollient effect of the polyphenols anddegreasing effect of the organic acids, a very goodenzymatic dirt cleaning capacity (Pruteanu et al.,2013a; 2013b; Sandu et al., 2012).

This article studies the cleaning capability of someorganic water systems, based on juices and uncoloredinfusions (freshly prepared) obtained from vegetablesand various indigenous plants, compared to the refer-ence alcohol-based solutions often used in cleaning of oldtempera painting. These alcohol solutions, besides theirtoxic effect on the curator, also have an aggressive actionon the patina and on the upper thin painting layers. Asa work procedure, cleaning tests were done on smallsurfaces with identical or similar colors. The nature ofthe deposits and the conservation state of the materialsused in painting were studied through SEM-EDX andmicro-FTIR, and the cleaning capability was analyzedby UV-vis reflectography and CIE L*a*b* reflection col-orimetry. As case study for the cleaning test a XIXthcentury icon, painted in egg tempera on lime wood, witha poor conservation condition and clogged dirt depositswas chosen. The icon is attributed to an anonymouspainter and to the neo-classical style of painting. Theicon represents the Three Hierarchs Saints—Basil,Gregory and John—from the Orthodox tradition.

EXPERIMENTAL PARTThe Icon Used in the Experiment

The icon used is painted in egg tempera on limewood, with a poor conservation state of the polychrome

Fig. 1. Icon of “Three Hierarchs Saints”—Basil, Gregory and John: (a) front, (b) back; (c) upperside; (d) lower side. [Color figure can be viewed in the online issue, which is available at wileyonlineli-brary.com.]

2 S. PRUTEANU ET AL.

Microscopy Research and Technique

http://wileyonlinelibrary.com


and a dark layer over the painting and also on theback of the icon (Fig. 1a and 1b).

The icon represents iconographic image of “ThreeHierarchs Saints”: Basil, Gregory, and John. It waspainted in neo-Byzantine style at the beginning of theXIXth century by an anonymous author. It is now afamily icon, donated to the owner from a Moldavianchurch collection.

The support is made out of a single lime wood panel,slightly curved at the ends, with two nails on the upperside, used to hang the icon to the wall. The lower sidehas a ditch for a now missing beam, used to stop thewood from getting curved (Fig. 1c and 1d). Icon has thefollowing dimensions: 24 cm length, 18 cm wide, and2 cm thick.

The conservation state is poor, besides from the dirtdeposits is suffering from ageing cracks, small gaps(some really old), blisters, cornification, and clogging.

Through visible and UV reflectography we canobserve previously cleaning operations (many yearsago), done in an empirical and aggressively way, by anunauthorized person.

The solution Used in CleaningThe Standard Solution. A solution of absolute

ethylic alcohol diluted with distilled water, named SS,was used as a reference system in order to evaluatethe cleaning capacity of the new natural organicallysystems taken into study. This solution was first opti-mized by performing cleaning tests outside the iconborders. Four different concentrations of ethylic alco-hol, low alkaline due to a few drops of ammoniac 25%:100%, 95%, 90%, and 85%. The literature tells thatethylic alcohol of 100% concentration, with a goodcleaning power for old tempera painting, has also thedisadvantage that it dehydrates the polychrome

layer, having sever consequences on the evolution ofthe conservation state. Diluting it to a lower concen-tration with distilled water has the disadvantagethat, through swelling and softening, it affects the oldpatina and the thin tints of tempera. Due to this, thestandard solution was the 95% concentration lowalkaline one, which provides a good cleaning and doesnot affect the old patina and the thin polychromelayers.

New Aqueous Micro-dispersed Systems Used inthe Washing Tests. A series of aqueous micro-dispersed simple (6), binary (5), or ternary (4) ecologi-cal systems, non invasive for old tempera was pre-pared as following:

S1 - corn silk infusion (Zea mays), obtained by boil-ing 10 g of corn silk in 200 mL of distilled water, for 5minutes;

S2 – 20 mL of uncolored fully grown pumpkin juice(Cucurbita pepo) removed by centrifugation andfiltration;

S3 – 20 mL of fully grown white onion juice (Alliumcepa) removed by centrifugation and filtration;

S4 – 20 mL of fully grown carrot juice (Daucus car-ota L.) removed by centrifugation and filtration;

S5 – 20 mL of fully grown celery (Apium graveolens)removed by centrifugation and filtration;

S6 – 20 mL of fully grown cabbage (Brassica olera-cea) removed by centrifugation and filtration;

S7 – 20 mL of dispersed binary system, corn silkinfusion*: uncolored fully grown pumpkin juice* 5 1:1;

S8 – 20 mL of dispersed binary system, corn silkinfusion*: fully grown white onion juice* 5 1:1;

S9 – 20 mL of dispersed binary system, corn silkinfusion*: fully grown carrot juice* 5 1:1;

S10 – 20 mL of dispersed binary system, corn silkinfusion*: fully grown celery* 5 1:1;

Fig. 2. The grid with the cleaning test squares (a) and the areas for taken samples (b) with paintingmaterial (PM). [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

CLEANING EFFECTIVENESS FOR NEW ECOLOGICAL SYSTEMS ON OLD TEMPERA ICON 3




S11 – 20 mL of dispersed binary system, corn silkinfusion*: fully grown cabbage* 5 1:1;

S12 – 15 mL dispersed ternary system, corn silkinfusion*: uncolored fully grown pumpkin juice*: fullygrown white onion juice* 5 1:1:1;

S13 – 15 mL dispersed ternary system, corn silkinfusion*: uncolored fully grown pumpkin juice*: fullygrown carrot juice* 5 1:1:1;

S14 – 15 mL dispersed ternary system, corn silkinfusion*: uncolored fully grown pumpkin juice*: fullygrown celery* 5 1:1:1;

S15 – 15 mL dispersed ternary system, corn silkinfusion*: uncolored fully grown pumpkin juice*: fullygrown cabbage* 5 1:1:1;

*the solutions used in the binary (S7–S11) and ter-nary (S12–S15) dispersions are prepared similar to thesimple systems S1–S6 and then mixed together in ratioprovided.

Cleaning Tests. The cleaning tests are a determi-nant factor in choosing the optimal cleaning systems,because the dispersion environments and the activeprincipals of the components can affect during clean-ing the old patina or they can remove the varnish andthin layer of color by swelling and softening or degrade

the binder or the pigments used by dissolution andleaching.

These tests were done both on polychrome surfaceand also on the back of the panel (on the original,untreated wood), by marking with a pencil Ceracoatsmall squares (1 cm2) in order to select areas withidentical or similar polychrome surface. Every timetwo squares were taken under testing, one for thestandard solution and the other one for the testsolution.

In Figure 2a you can see the grid with the delimita-tion of the washing tests. The concentration of thealcoholic and low alkaline cleaning solutions was opti-mized on the first two series of squares from the upperside of the grid, the rest of the squares being submittedto the cleaning tests with the aqueous simple, binary,and ternary systems.

The cleaning was done in consecutive stages byremoval using cotton swabs. For every cleaning stage,the chosen square was wet with the cotton swabsoaked in the solution tested, by passing it over thesurface of the square only once, in a certain direction.Immediately after the softening the square wascleaned with a new semi-humid cotton swab. The wip-ing was performed alternately on perpendicular

Fig. 3. SEM microphotographs of the painting layer samples: (a) PM1, (b) PM2, (c) PM3, (d) PM4, (e) PM5, (f) PM6.



directions. The entire operation was repeated 10 times,on a 5 minutes interval.

In order to determine the conservation state of theicon and to identify the materials used to create it, sixsamples of painting layer were taken from the crackedareas, with singular pigments, notate PM1–PM6 (Fig.2b). In selecting the six samples, the following parame-ters were taken into consideration: the homogeneity ofthe deposits, their adherence to the painting layer, thenature of the pigments and the binder’s and varnish’sstate of conservation. These samples were analyzedthrough UV-Vis reflectography, before and after thecleaning test with the standard solution (on a smallsurface, <0.4 cm2). This study has required a goodknowledge of the nature of old painting materials anddeposits, which allowed beside the determination ofthe conservation state, the identification of attributesrequired in order to authenticate the icon.

The Analysis of the Painting Materials Used andof the Cleaning Capacity

The cleaning capacity was analyzed, similar to otherprevious studies (Sandu et al., 2000, 2001c; 2006;2007; 2008a; 2008b; 2009; 2011a, 2011b; 2013), bydirect observation with eyes and also through UV andvisible reflectography, CIE L*a*b* reflection colorime-try and by means of SEM-EDX and micro-FTIRspectroscopy.

Initially, by UV and visible reflectography the stateof conservation of the painting layer and of the back ofthe panel was analyzed, obtaining information aboutthe homogeneity of the dirt deposits. According toother authors, the same technique was used to studydifferent previous interventions of replacing the oldvarnish with a new one (Traistaru et al., 2012, 2013).

The evaluation of colors changes and of the cleaningdegree was done with LOVIBOND RT Series spectro-photocolorimeter (Reflectance Tintometer). Thisallowed the direct recording from the sample of thecolor deviation, before and after the washing. The datawere transferred to the computer and were processed.

For graphical representation of colorimetric values ofthe samples analyzed the CIE L*a*b* space proposed bythe International Commission on Illumination (CIE) in1976, was used. The hue in this space (represented bybasic colors: red, green, blue, etc.), brightness or clarity

(color ranging from black to white) and color (the colorpurity through its saturation, meaning its maximumbrightness that appears for given added color), are ana-lyzed on three axes: L*, a*, and b*. The axis 0X, notedwith a*, it represents chromatic variation from red togreen (a* axis it refers to the chromatic red—a*> 0 andgreen—a*< 0), while b* represents the axis 0Y, theother two chromatic stimuli, yellow (b*> 0), and blue(b*< 0), and L* represents the axis 0Z, the brightness.This method of representation of color (Sandu et al.,2006, 2008b; 2009) by means of Cartesian coordinates isbased on the consideration that no color can be red orgreen and yellow and blue at the same time (so it isassumed that there is a complementary red/green andblue/yellow). At the painting cleaning the basic princi-ples of intervention were respected (Sandu et al., 2010b,2011a), by testing the solutions on different types ofdeposits, and according to their state of preservation.

For analyzing the painting materials (compositionand morphological structure), a VEGA II LSH scanningelectron microscope (SEM), made by TESCAN in theCzech Republic, coupled with a QUANTAX QX2 EDXdetector, made by BRUKER/ROENTEC in Germania,were used. The samples were analyzed under a 200–250X magnification, with an accelerate tension of 30 kV,and a work pressure lower than 1 3 1022 Pa. The imageobtained was constituted by the secondary electrons(SE) and by the backscattered electrons (BSE).

Also, in order to determine the composition, IR spec-tra recorded with a FTIR spectrometer, coupled with aHYPERION 1000 microscope, both from Bruker Optic,Germania, were acquired. The FTIR spectrophotometeris a TENSOR 27 type, suitable mainly for near infraredmeasurements. The standard detector is a DLaTGStype, which for our analysis, has covered the spectraldomain between 4000 and 600 cm21. The TENSOR iscompletely controlled by the OPUS soft, which acquiresinteractive video data and uses libraries of adequatespectrums for different types of materials. The micro-scope is equipped with a 15X lens objective.

RESULTS AND DISCUSSIONSThe Identification of Painting Materials and the

Conservations State Evaluation

The Figure 3 presents the SEM microphotographs ofthe samples PM1–PM6. Based on the EDX analyses,

TABLE 1. The elemental composition in gravimetric percentages of painting materials and dirt deposits

Sample

The elemental composition in gravimetric percentages (%)

Si Al Fe Pb Ca Mg Ba K P S Au Ag C O

PM1 0.254 0.078 – 1.623 1.379 – – – – – 3.708 1.109 28.522 63.328PM2 3.530 1.674 1.102 6.423 3.184 1.154 – 1.169 0.320 3.048 – – 14.930 63.466PM3 6.842 3.148 1.851 4.725 3.885 1.830 – 0.713 0.496 3.400 – – 9.410 63.700PM4 A1 – – – 12.393 0.239 – 1.427 0.070 – 0.821 – – 22.935 62.079

A2 1.412 0.254 – 8.080 1.117 – – 0.202 – 0.210 – – 24.436 64.289A3 10.092 3.112 1.319 10.908 3.344 1.758 3.685 1.954 1.302 1.897 – – 17.367 43.262

PM5 B1 0.905 0.769 0.789 12.351 0.933 – – 0.574 – – – – 19.446 64.233B2 6.193 1.854 3.255 15.107 4.552 0.096 1.212 0.535 – – – – 6.413 60.771B3 0.982 0.448 0.796 15.503 0.778 – 0.686 0.248 – 0.956 – – 23.005 56.599

PM6 C1 1.292 0.494 0.455 19.444 0.564 – – – – 0.916 – – 17.935 58.899C2 14.862 5.568 2.231 11.098 3.228 1.415 2.767 1.987 – 1.787 – – 9.138 45.919C3 – – – 19.192 – – – – – – – – 23.094 57.714C4 – – – 9.882 – – – – – – – – 28.798 61.320C5 – – – 7.428 0.558 – – – – 1.125 – – 28.161 62.728C6 0.501 0.196 – 20.218 0.954 – – 0.379 – 1.446 – – 15.956 60.350



we evaluated the elementary gravimetric percentagecomposition (Table 1) on the entire surface of the SEMmicrophotography, of some relatively well preserved col-ors (Fig. 3a–3c) and on some colors and varnish affectedby dirt deposits, different in morphology and distribu-tion (Fig. 3d–3f). These data were correlated with datafrom the micro-FTIR spectroscopy (Fig. 4) in order toidentify the pigments, the binders, nature of the dirtdeposits and to establish their conservation state.

The composition data from Table 1 confirm thechemical nature of the primary pigments used in creat-ing the icon, except the binder based on egg emulsionand the organic dirt, represented by a part of carbonand oxygen composition (rest of it comes from carbo-nates, sulfates, phosphates, oxides and chemical boundwater as crystal hydrates, aquo-, and hydroxy-com-plexes). So, the following pigments were identified:

A. gilding based on gold powder with silver, on thehalos (PM1) and on the clothes of Saint Gregory;

B. Green-khaki, obtained by mixing the ultramarineblue with litharge yellow or massicot and leadwhite (PM2);

C. Red based on ultramarine red and lead minium(PM3);

D. Light lime green, obtained by mixing green pigment(from ultramarine blue combined with litharge yel-low or massicot) with lead white—cerussite andbarium white—barium sulfate (PM4);

E. Blue, based on ultramarine blue, mixed with verylittle lead white and barium white (PM5);

F. Lead white, mixed with barium white (barium sul-fate) and gypsum (calcium sulfate de-hydrated);

By corroborating these data with those obtained bymicro-FTIR spectroscopy (Fig. 4 and Table 2) we con-firmed the nature of the pigments and determined theegg emulsion-based binder and the resin-based Dam-mar varnish, and also that of the organic deposits, likegrease from the hands and tars that resulted fromburning lamps and candles during mass.

The preparation was identified as a thin layer ofbrown ground, which contains lead minimum mixedeither with earth white and calcium carbonate (PM1),either with barium sulfate/carbonate and calcium(PM4-A1; PM5-B3), or with barium sulfate and cal-cium (PM6-C2). Ivory black (C), used in shading andborders, can be found in all six samples, overlappingthe tar and grease deposits. The ivory black is the onlypigment used in the neo-classical painting from Mol-dova and it was detected based on the analysis SEM-EDX as C, that has a higher % (more than 28%) insamples PM1, PM6-C4, and PM6-C5.

The painting is in egg tempera with ochre, yellow,blue and red (earth colors), lead white, barium whiteand calcium white, ivory black and India ink for shadowand borders, together with gold leaf for the halos andSaint Grigory’s clothes. The varnish is a very thin layerof Dammar resin and is highly degraded.

The protocol of choosing this icon for this study tookinto consideration the fact that in evaluating the effi-ciency of cleaning with the new aqueous systems, pre-pared according to the experiment, requires theexistence of surfaces with uniform distributed dirtdeposits, of painting materials of the same or similarnature (in our case pigments from the group of earthcolors, egg based binder/ and Dammar resin based var-nish). The paint layer of the icon was made with asmall range of earth pigments, used by old iconpainters, during the XVII-XIXth centuries, in theEastern European space, with Byzantine influences.Because the icon was originally intended for liturgicalactivities and after it become a family icon and endedup in a private collection, it acquired dirt deposits overtime, which through oxidation becomes clogged andcornified.

The fact that deposits were not uniform on the twosurfaces, the painting layer and the back of the icon,allowed a different evaluation of the cleaning efficiencyof each one of the three groups of dispersed systemstaken into study: simple, binary and ternary.

Fig. 4. Micro-FTIR spectra of the painting material samples. [Color figure can be viewed in the onlineissue, which is available at wileyonlinelibrary.com.]




The Evaluation of the Cleaning SystemsEffectiveness

First, the standard cleaning solution was optimized byanalyzing the behavior of absolute ethylic alcohol duringcleaning, which was gradually diluted. In order to maxi-mize its efficiency, a few drops of ammoniac 25% wereadded in the alcohol solution which became alkaline.

Figure 5 shows the squares from the upper part ofthe icon, on which the test for optimizing the standardsolution (E1, E2, E3, and E4) took place. The fact thatthe alcohol of 100% concentration cleans the best (Fig.5a), but generates dehydration cracks (as shown in allfour squares), was observed both with the naked eyeand by reflection colorimetry. The 95% concentrationalcohol ethylic solution, tested in the squares b, keepthe same quality of cleaning, but without the cracks(Fig. 5b). The 90% solution tested in the squares c, pro-vides a lower quality of cleaning (Fig. 5c), and the oneof 85% concentration, tested in the d squares, is evenweaker (Fig. 5d). A few drops of 25% ammoniac wereadded to all this four alcoholic testing solutions, inorder to make them slightly alkaline.

A solution of 95% ethylic alcohol (E2), diluted withdistilled water (Fig. 5b) was used as a reference to com-pare the cleaning capacity of the ecological organic sys-tems from juices and infusion herbs from indigenousplants (S1–S15).

The Figure 6 presents the areas used to test the nat-ural aqueous micro-dispersion taken into study forboth sides of the icon. For each system two squaresgroups with identical or similar polychrome layerswere chosen, one group for the standard solution (thesquares from the left side) and one group for the aque-ous micro-dispersion (squares 1–6 were cleaned withS1–S6; those from 7 to 11 with the binary systems S7–S11, and the ones from 12 to 15 were washed with ter-nary systems S12–S15).

The 15 dispersive systems were tested and comparedwith the standard solution (E1, E2, E3, and E4) both onthe front and on the back of the panel (Fig. 6a and 6b).

The best results, observed by naked eye and byusing UV and visible reflectography, were obtainedwith S2 and S3 simple dispersions, with S8 and S9binary dispersions and with S14 and S15, for ternarydispersions.

TABLE 2. Representative peaks and spectral bands of the ions identified in the samples analyzed by micro-FTIR

Type ionTheoretical Spectral

bands (cm21) Peak present in samples (cm21)Samplesanalyzed

Silicate 860–1175 947.61; 1064.75 PM11146.72 PM21135.67 PM3939.18; 1057.36 PM41068.26 PM51130.54 PM6

Aluminate 800–920 836.37 PM2811.68 PM3889.29 PM4810.83 PM5821.66; 887.96; PM6

Sulphate and sulphide 570–680; 960–1030 618.31 PM2649.76 PM3632.19 PM41007.26 PM5654.38 PM6

Carbonate 670–745; 800–890;1040–1100; 1320–1530

1333.28; 1382.81; 1461.93 PM1692.45; 726.29; 1459.25; PM2699.07; 1337.47; 1391.82; 1477.59 PM3736.02; 1323.76; 1395.03; 1474.77 PM4731.84; 1332.92; 1471.56 PM51334.16; 1493.05 PM6

Phosphate 830–920; 1600–1900;2150–2500; 2750–2900

2194.16; 2258.00; 2473.57 PM22497.89 PM3841.86 PM4

Pb(II, IV) as oxydes and carbonated 660–685 683.48; 684.49; PM1–PM6Fe(II, III) as oxydes 700–715 712.49; PM2–PM6Aquo and hydroxy complexes

(coordination and crystallized water)2850–4000 2862.71; 2942.64; 3427.39 PM1

3423.85; 3634.10 PM22871.37; 3565.97 PM32871.69; 2970.02; 3535.17 PM42861.55; 2965.23; 3547.92 PM53446.50 PM6

Binder (egg protein identifiedby amide I and II)

�1547; 1621–1690 1596.68 PM21588.82 PM31672.23 PM41552.21 PM51545.86; 1680.20 PM6

Varnish (Dammar – by ester groups) �1265; �1750 1742.05 PM11736.97; 1271.45 PM21753.19; 1265.80 PM31750.29; 1289.29 PM41748.92 PM51784.28; 1292.53 PM6

Tar and fats, as carbonyl and carboxyl groups 1950–2050 2550–2750 1950–2050; 2650.99 PM1–PM6



Fig. 5. Detail with the squares for the cleaning test with alcoholicsolutions: (a) first four cleaned with absolute ethylic alcohol 100%(E1); (b) the next four cleaned with ethylic alcohol of 95% (E2); (c) the

next four cleaned with ethylic alcohol of 90% (E3); (d) the last twocleaned with ethylic alcohol 85% (E4). [Color figure can be viewed inthe online issue, which is available at wileyonlinelibrary.com.]

Fig. 6. (a) Front side of the icon, details with the squares for clean-ing with the aqueous natural systems (1–15) and 95% alcoholic solu-tion (those squares on the left side, without numbers); (b) back side ofthe icon, details with the squares for cleaning with the aqueous natu-

ral systems (1–15) and 95% alcoholic solution (those squares on theupper raw, without numbers). [Color figure can be viewed in theonline issue, which is available at wileyonlinelibrary.com.]





The results were confirmed by CIE L*a*b* reflectioncolorimetry, when DE* was evaluated according to therelation (Sandu et al., 2000, 2001c):

DE �5 DL�ð Þ21 Da�ð Þ21 Db�ð Þ2h i1=2

; (1)

for each one of the 10 alternative cleaning stages.The colorimetric data (Fig. 7) were correlated with

the data obtained by SEM-EDX (Fig. 3 and Table 1)and micro-FTIR (Fig. 4 and Table 2).

In Figure 7a–7c, and d it can be observed the factthat the tested alcoholic solution used as reference(E1–E4) and the aqueous micro-dispersions from juicesand herb infusion uncolored and fresh (S1–S15) haverates upward, somewhat different from each other.After the first three washes, there is slight drop,caused by the softening capability of the active compo-nents of the micro-dispersions, and afterward there isa slight increase in the value of DE* up to step 6, thateventually grow asymptotic the abscissa.

The data for Figure 7 presents the evolution of DE*for four alcoholic solutions (100%, 95%, 90%, and 85%)with a few drops of ammoniac 25%, used in cleaning,where it can be noticed that the absolute alcohol is

more efficient than 95% solution, but it has the disad-vantage that by dehydration produces cracks into thepaint layers. For these reasons, as reference systemthe E2 solution was used, compared with the othernew natural systems of cleaning.

The data for Figure 7b show that the system simpleS2—pumpkin juice based—is the most effective one,and the simple system S2, based on celery juice is theleast efficient one.

Figure 7c shows that the binary system most effec-tive in cleaning the painting is S8 (corn silk infusion:white onion juice 5 1:1), which cleans well after thefirst three stages, followed by S9 (corn silk infusion:uncolored carrot juice 5 1:1), which reaches the sameefficiency after eight stages. We should notice that thevalue of DE* for the binary systems drops at almosthalf of that of the simple systems, fact caused by anincompatibility between the components of the twomixed simple systems or by the difference in the waythe dirt deposit id glue to the polychrome layer and thedegree in which the pigments used were mixed.

The greatest efficiency of cleaning, in the ternarysystems (Fig. 7d), belongs to S14, a mix of corn silkinfusion, pumpkin juice, and uncolored celery juice in1:1:1 ratio. The value of DE* of the ternary systemsalso drops to half of the value of the simple systems.

Fig. 7. The evolution of DE* compared with the stage of the cleaning with: (a) alcoholic solution of ref-erence E1–E4; (b) simple micro-dispersions S1–S6; (c) binary micro-dispersions S7–S11; (d) ternarymicro-dispersions S12–S15. [Color figure can be viewed in the online issue, which is available at wileyon-linelibrary.com.]





Causes of this effect are the same described above, byan incompatibility between the components of the twomixed simple systems or by the difference in the waythe dirt deposit id glue to the polychrome layer and thedegree in which the pigments used were mixed.

CONCLUSIONS

The old icon studied is a egg tempera painting, in apoor conservation state, made on lime wood, in neo-Byzantine style a with just a handful of earth color pig-ments, gold-silver powder, red minium and lead white,barium sulfate/carbonate and calcium, all these on athin layer of brown ground, that contains lead miniummixed with earth white and barium sulfate/carbonateand calcium. The binder is based on egg emulsions andthe resin based varnish is Dammar, mixed with organicdirt deposits like grease and tar obtained as a secondaryproduct from burning lamps and candles. The color ivoryblack, used for shadows and borders, can be found in allsix samples, overlapping the grease and tar deposits.

The evaluation of cleaning effectiveness by usingecological aqueous systems based on juices and uncol-ored infusion obtained from indigenous plants, wasdone with the naked eye and by UV-Vis reflectographyand reflection colorimetry, by comparing their effi-ciency with that of the SS of 95% ethylic alcohol, inwhich a few drops of 25% ammoniac was added tomake it slightly alkaline. Three groups of aqueousmicro-dispersion system based on juices and infusionswere taken into study: simple (6), binary (5), and ter-nary (4). The CIE L*a*b* colorimetric measures of thecleaned surfaces have reveled the fact that the simplesystems S2-based on pumpkin juice is the most effi-cient one, and the S5-based on celery juice is the leastefficient one: for the binary systems, the most efficientone is S8 (corn silk infusion: white onion juice 5 1:1),which cleans well after the first three stages, then theS9 (corn silk infusion: carrot uncolored juice 5 1:1)which reaches the same performance after eight stagesof cleaning. In the same way, the ternary system S14,based on a mix of corn silk infusion, pumpkin juice anduncolored celery juice, on a 1:1:1 ratio, is the most effi-cient one, but its weaker than the simple system S2,because the value of S14’s DE* drops to almost half ofthe one of S2 system, being closer to the value of S8.

We should notice that the value of DE* for binary andternary systems drops to almost half in comparison tothe DE* value of the simple systems, due to incompati-bility between the components of the two mixed simplesystems or it is caused by the difference in the way thedirt deposit is glued to the polychrome layer and thedegree in which the pigments used were mixed.

References

Bonini M, Lenz S, Giorgi R, Baglioni P. (2007). Nanomagneticsponges for the cleaning of works of art. Langmuir 23:8681–8685.

Branco LC, Carrera GVSM, Aires-de-Sousa J. (2011). Physico-chemical properties of taskspecific ionic liquids. In: Kokorin A, edi-tor. Ionic liquids: Theory, properties, new approaches. InTech,Rijeka, Croatia, pp. 61–94.

Brandi C. (1977). Teoria del restauro, Edizioni di Storia e Lettera-tura. Einaudi Editore, Torino, Italia.

Burnstock A, White R. (1990). The effects of selected solvents andsoaps on a simulated canvas painting, in Preprints of the 13thBiennial IIC Congress Cleaning, Retouching and Coatings, Inter-national Institute for Conservation of Historic and Artistic Works,Brussels, pp. 111–118.

Calvo A. (2002). Conservaci�on y restauraci�on de pintura sobre lienzo.Serbal, Barcelona.

Carretti DL, Macherelli A. (2004). Rheoreversible polymeric organo-gels: The art of science for art conservation. Langmuir 20:8414–8418.

Domingues J, Bonelli N, Giorgi R, Fratini E, Baglioni P. (2013). Inno-vative method for the cleaning of water-sensitive artifacts: Synthe-sis and application of highly retentive chemical hydrogels. Int JConserv Sci 4:715–722.

Khandekar N. (2000). A survey on the conservation literature relat-ing to the development of acqueous gel cleaning on painted andvarnished surfaces. Rev Conserv 1:10–20.

Kuckova S, Sandu ICA, Crhova M, Hynek R, Fogas I, Muralha VS,Sandu AV. (2013a). Complementary cross-section based protocol ofinvestigation of polychrome samples of a 16th century MoravianSculpture by optical, vibrational and mass spectrometric techni-ques. Microchem J 110:538–544.

Kuckova S, Sandu ICA, Crhova M, Hynek R, Fogas I, Schafer S.(2013b). Protein identification and localization using mass spec-trometry and staining tests in cross-sections of polychrome sam-ples. J Cult Herit 14:31–37.

Hrdlickova Kuckova S, Crhova Krizkova M, Pereira CLC, Hynek R,Lavrova O, Busani T, Branco LC, Sandu ICA. (2014). Assessmentof green cleaning effectiveness on polychrome surfaces by MALDI-TOF mass spectrometry and microscopic imaging. Microsc ResTech 77:551–560.

Magrini D, Bracci S, Sandu ICA. (2013). Fluorescence of organic bindersin painting cross-sections, in “Youth In the Conservation of CulturalHeritage”, YOCOCU 2012 (Edited by Macchia A, Greco E, Cagno Sand Prestileo F), Book Series: Procedia Chemistry, 8:194–201.

Michalski S. (1990). Cleaning, retouching and coatings: Technologyand practice for easel paintings and polychrome sculpture. Brus-sels: International Institute for Conservation of Historic and Artis-tic Works.

Mills JS, White R. (1994). The organic chemistry of museum objects.London: Butterworth-Heinemann.

Oujja M, Sanz M, Rebollar E, Marco JF, Domingo C, Pouli P, Kogou S,Fotakis C, Castillejo M. (2013). Wavelength and pulse durationeffects on laser induced changes on raw pigments used in paint-ings. Spectrochim Acta, Part A-Mol Biomol Spectrosc 102:7–14.

Pacheco MF. (2010). Remoc~ao de vernizes de pinturas utilizandol�ıquidos i�onicos, Master Thesis. Lisbon: New University of Lisbon.

Park S, Kazlauskas R. (2003). Biocatalysis in ionic liquids—Advan-tages beyond green technology. Curr Opin Biotechnol 14:432–437.

Pereira C, Busani T, Branco LC, Joosten I, Sandu ICA. (2013a). Non-destructive characterization and enzyme cleaning of painted surfa-ces: Assessment from the Macro to Nano level. MicroscMicroanalysis 19:1632–1644.

Pereira C, Ferreira I, Branco LC, Sandu ICA, Busani T.(2013b). Atomic Force Microscopy as a valuable tool in an innovativemulti-scale and multi-technique non-invasive approach to surfacecleaning monitoring, In Macchia A, Greco E, Cagno S and PrestileoF, editors. youth in the conservation of cultural heritage, YOCOCU2012, Book Series: Procedia Chemistry, Vol. 8, pp. 258–268.

Phenix A, Sutherland K. (2001). The cleaning of paintings: Effects oforganic solvents on oil paint films. Rev Conserv, 2, 47–60.

Pouli P, Emmony DC. (2000). The effect of Nd: YAG laser radiation onmedieval pigments. J Cult Herit, 1:S181–S188.

Pouli P, Emmony DC, Madden CE, Sutherland I. (2003). Studiestowards a thorough understanding of the laserinduced discolora-tion mechanisms of medieval pigments. J Cult Herit 4:271s– 275s.

Pouli P, Oujja M, Castillejo M. (2012). Practical issues in laser clean-ing of stone and painted artefacts: Optimisation procedures andside effects. Appl Phys A-Mater Sci Process 106:447–464.

Pruteanu S, Sandu I, Vasilache V, Gherman LG, Sandu ICA,Cristache RA. (2013). Integrated analytical study for the evalua-tion of cleaning effectiveness on Old Wood Romanian Icons. ProLigno 9:242–250.

Pruteanu S, Gherman LG, Sandu I, Hayashi M, Cozma DG,Vasilache V, Sandu ICA. (2013). Ecological materials used in pres-ervation and restoration on new wood, Pro Ligno 9:265–275.

Ruhemann, H. (1968). The cleaning of paintings: Problems and poten-tialities. New York: Frederick A Praeger Publishers.

Sandu I. (2008). Degradation and deterioration of the cultural herit-age, Vol. II, Iasi: “Al.I.Cuza” University Publishing House.

Sandu ICA, Bracci S, Loberfaro M, Sandu I. (2010b). Integratedmethodology for the evaluation of cleaning effectiveness in twoRussian icons (16th-17th centuries). Microsc Res Tech 73:752–760.

Sandu ICA, Bracci S, Sandu I. (2006). Instrumental analyses used inthe authentification of old paintings - I. Comparison between twoicons of XIXth century. Revista de Chimie (Bucharest) 57:796–802.



Sandu ICA, Bracci S, Sandu I, Loberfaro M. (2009). Integrated ana-lytical study for the authentication of five Russian icons (XVI-XVIIcenturies). Microsc Res Tech 72:755–765.

Sandu ICA, Brebu M, Luca C, Sandu I, Vasile C. (2003). Thermogra-vimetric study on the ageing of lime wood supports of old paintings.Polym Degrad Stabil 80:83–91.

Sandu ICA, Busani T, de Sa MH. (2011b). The surface behavior ofgilding layer imitations on polychrome artefacts of cultural herit-age. Surf Interface Anal 43:1171–1181.

Sandu ICA, de Sa MH, Pereira MC. (2011a). Ancient ‘gilded’ artobjects from European cultural heritage: A review on differentscales of characterization. Surf Interface Anal 43:1134–1151.

Sandu ICA, Luca C, Sandu I. (2000). Study on the compatibilitybetween the old artistic techniques and the new materials andmethods for the conservation - Restauration processesinventations. I. Theoretical aspects. Revista de Chimie (Bucharest)51:532–542.

Sandu ICA, Luca C, Sandu I, Atyim P. (2001b). Research regardingthe soft wood support degradation evaluation in old paintings,using preparation layers. 1. Chemical composition and technicalanalysis, Revista de Chimie (Bucharest) 52:46–52.

Sandu I, Luca C, Sandu ICA, Ciocan A, Suliteanu N. (2001c). A studyon the compatibility of the old, traditional artistical techniqueswith the new materials and methods used in the restauration, pres-ervation processes. II - A chromatic analysis. Revista de Chimie(Bucharest) 52:485–490.

Sandu ICA, Luca C, Sandu I, Pohontu M. (2001a). Research regard-ing the soft wood support degradation evaluation in old paintings,using preparation layers. II. IR and FTIR Spectroscopy Revista deChimie (Bucharest) 52:409–419.

Sandu ICA, Luca C, Sandu I, Vasilache V, Sandu IG. (2002). Researchconcerning the evaluation of the ageing of some soft weed supportsof old paintings with preparation layer. III - The thermogravimetricanalysis, Revista de Chimie (Bucharest) 53:607–615.

Sandu I, Luca C, Sandu ICA, Vasilache V. (2007). Old paintingsauthentication through the identification of the polychrome layersmaterials - I. Gas-cromatography analyse. Revista de Chimie(Bucharest) 58:879–866.

Sandu ICA, Luca C, Sandu I, Vasilache V, Hayashi M. (2008b).Authentication of the ancient easel paintings through materialsidentification from the polychrome layers - II. Analysis by means of

the FT-IR spectrophotometry. Revista de Chimie (Bucharest) 59:384–387.

Sandu ICA, Murta E, Veiga R, Muralha VS, Pereira M, Kuckova S,Busani T. (2013). An innovative, interdisciplinary, andmulti-technique study of gilding and painting techniques inthe decoration of the main altarpiece of Miranda do Douro Cathedral(XVII-XVIIIth centuries, Portugal). Microsc Res Tech 76:733–743.

Sandu I, Vasilache V, Sandu ICA, Hayashi M. (2010a). A new methodof determining the normal range of hydric-equilibrium variation inwood, with multiple applications. Revista de Chimie (Bucharest)61:1212–1218.

Sandu ICA, Vasilache V, Sandu I, Luca C. (2008a). Authentication ofthe ancient easel-paintings through materials identification fromthe polychrome layers III. Cross - section analysis and stainingtest. Revista de Chimie (Bucharest) 59:855–886.

Sandu I, Vasilache V, Sandu ICA, Gherman LG, Pruteanu S. (2012).Nout�ati ın conservarea s, tiintific�a a lemnului vechi pus ın oper�a.Tehnocopia, Chisin�au 2(7):5–27.

Siano S, Agresti J, Cacciari I, Ciofini D, Mascalchi M, Osticioli I,Mencaglia AA. (2012). Laser cleaning in conservation of stone,metal and painted artifacts: State of the art and new insights onthe use of the Nd:YAG lasers. Appl Phys A-Mater Sci Process 106:419–446.

Teixeira SJV. (2011) Hidr�olise Enzim�atica das Prote�ınas da Dreche,Master Thesis. Porto: University in Porto.

Traistaru AAT, Sandu ICA, Timar MC, Dumitrescu GL, Sandu I.(2013). SEM-EDX, water absorption, and wetting capability studieson evaluation of the influence of nano-zinc oxide as additive toparaloid B72 solutions used for wooden artifacts consolidation.Microscopy Res Techn 76:209–218.

Traistaru AAT, Timar MC, Campean M, Croitoru C, Sandu I. (2012).Paraloid B72 versus paraloid B72 with Nano-ZnO additive as con-solidants for wooden artifacts. Materiale Plastice (Bucharest) 49:293–300.

Vounisiou P, Selimis A, Tserevelakis GJ, Melessanaki K, Pouli P,Filippidis G, Beltsios C, Georgiou S, Fotakis C. (2010). The use ofmodel probes for assessing in depth modifications induced duringlaser cleaning of modern paintings. Appl Phys A-Mater Sci Process100:647–652.

Wolbers R. (2003). Cleaning Painted Surfaces, Aqueous Methods.London: Archetype Publications.



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