Università degli Studi di TorinoCorso di Laurea Magistrale in

Conservazione e Restauro dei Beni Culturali

Relatore

Francesca Spagnoli

Referente storico-artistico

Prof. Maria Beatrice Failla

Referente scientifico

Prof. Eliano Diana

A.A. 2011-2012

PROVA FINALE

WOODEN ARCHAEOLOGICAL OBJECTS FROM THE CHU KINGDOM (V-III SEC. B.C.). A STUDY OF THE CHINESE LACQUERS USED AND CONSERVATION

INTERVENTION”.

Corelatori

Dott. Tiziana Cavaleri

Dott. Flavio Ruffinatto

Dott. Anna Piccirillo

Candidata

Simonetta Capetta

ATTENDANT TOMB GUARDIAN

DRUM ELEMENTS

front back front back

Polychrome wooden artefacts coming from the south-central China at the Museo di Arte Orientale (MAO) of Turin.

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ARCHAEOLOGICAL WOODEN OBJECT FROM THE CHU KINGDOM: description 2

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THE CHU KINGDOM: burials

Maximum expansion of the Chu Kingdom.

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The works come from a funerary equipment belonging to the Chu kingdom aristocracy.

The Kingdom developed from the seventh to the third century BC had an important influence in the formation of Chinese civilization and spreaded over most of southern China.

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THE CHU KINGDOM: burials

Manufatti lignei policromi provenienti dall’area centro-meridionale della Cina

2 Tomb at Baoshan.

Wooden coffins and external boxes.

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The burials for the aristocracy were formed by multilayer coffins located in a deep hole, surrounded by a layer of charcoal and a thicker white clay. Tombs with steps and one or more ramps covered with mounds of different land fill.

The space between the outer chamber and the walls of the coffin was often filled with funerary objects.

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THE CHU KINGDOM : lacquers

Bird lacquered wooden base shaped like a tiger

Horned Deer inlacquered wood.

Lacquered vase for liquids(dou).

Launched a study andexperimentation onChinese lacquer to supportdecisions about therestoration choices.

Lacquers, known in ancientChina from the Neolithicperiod, a by the Chucraftsmen.re subsequently adopted

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Lacquered coffin.

Figure Attendant used in burials as a helper of the deceased on his journey into the underworldThe status is constituted by a single element of wood

ATTENDANT: executive tecnique

Chessboard decorations for the garment.A red belt at the waist wraps around the figure

on the front and back.In front are visible two elements referable to a

sort of pendant.

Comparisons with similar figures of attendants in carved wood (IV-III century BC.).

6Sizes: 120x540x70 mm.

SUBSTRATE:Shrinkage cracks caused by quick thermo-hygrometric changes. Deep cracks. Lacunae of wooden fragments in the area of the base. Lacunae of elements: removable arms and feet.

ATTENDANT: conservation status

POLYCHROMY:Presence of lacunae.

Crimp and pulverization of the lacquer. Discoloration.

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7TOMB GUARDIAN: executive tecnique

The guardian of the tomb was used to protect the deceased from evil spirits, and he has a long tongue and protruding eyes. He is made by two wooden elements manufactured in a single piece of wood.

The basement is carved according to simple geometric planes.

The body is inserted into the base through a recess on the top.

The red decorations on the sculpture consist in swirls and spirals, combined with simple

motif like meander and crossed lines.

8Size: 2250x395x190 mm.

Comparison with a similar figure of Guardian of thetomb Zhenmushou.

SUBSTRATE:Shrinkage cracks caused by quick thermo-hygrometric changes. Deep cracks. Lacunae of fragments of wood in the area of the base and the head. Lacunae of elements: horns.

TOMB GUARDIAN: conservation status 9

POLYCHROME:Lacunae of polychrome and surface severely

depleted.

TOMB GUARDIAN: conservation status 10

PREVIOUS INTERVENTIONS:Presence of a pin in fiberglass.Filling of deep cracks on the base and on the body of the monster.Repainting.

Wood elements belonging to one or more drums rituals, assembled together to form a circular frame supported by pillars representing cranes. Presence of holes for the housing of the wooden pins to tension the drum skins. The Cromia consists of a rather impoverished black layer, with some traces of red. Presence of lacunae.

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DRUM’S ELEMENTS: executive technique and conservation status 11

Grafico che identifica la perdita della curvatura originale.Drum support.

Lacquer craquelureTypical cracks "buttonhole", caused by a quick collapse of the cellular structure.

Drum elements

ATTENDANT

Minor wood density in thebase of the figure as a resultof the degradation of thesubstrate.

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NON INVASIVE ANALYSIS: X-ray

Tomb guardian

Attendant figure.

Drum elements.

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TOMB GUARDIAN

Difference in radio-opacity inthe peripheral areas of thebase caused by the filling ofcracks.

Evidence of the depth ofinsertion of the fiberglasspin.

DRUM’S ELEMENTS

Evidence of cracks and porous ring.

100 a 200 KV e da 4,5 mA a 8 mA.

The red pigment (cinabro) gives a yellow-green colouration.

NON INVASIVE ANALYSIS Infrared in false color

Attendant figure, detail of the decoration ofthe belt; microscope image in false color.

Tomb guardian, detail of the decoration of thebasement; microscope image in false color.

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Tomb guardian. Attendent figure

Touch microscope

NON INVASIVE ANALYSIS Ultra violet 14

Tomb guardian, ultra-violet images.

Previous interventions:

Higher fluorescence in the areas of bonding (yellow boxes) and in the presence of fillings (red box).

Wood species recognition byoptical microscopyobservation of anatomicalcharacters.

FIGURE OF ATTENDANT, THE GUARDIAN BASEMENT

Lauraceae family, Medang group.

More than 35-45 genera anddifficulties in discriminatingbetween species for thepresence of similar anatomicalcharacters.

DRUM ELEMENTSLauraceae family, Medang group,

Gender Sassafrass

BODY OF THE TOMB GUARDIAN

Gender Populos (Pioplar).

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Radial section,drums elements. Transversal section, attendant figure.

Radial section, tomb guardian basement. Tangential section, tomb guardian body.

15NON INVASIVE ANALYSIS : wood species recognition

16NON INVASIVE ANALYSIS : wood species recognition

The most popular genera are:

Lindera, Litsea,

Machilus,Neolitsea, Phoebe,

Sassafrass.

Areas of greatest expansion of the Chu kingdom in relation to current areas of diffusion of the different species of the Lauraceae family in the Chinese territory

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NON INVASIVE ANALYSIS : Micro-Raman, Pyrolysis mass

Raman spectrum from the sample of black patina. Black coal.

Raman spectrum from the sample of red pigment. Cinnabar.

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Diagnostic studies have been useful inreconstructing of the conservationhistory and the technique of theartifacts.

• Micro Raman to investigate the natureof the pigments;

• Fourier transform infrared spectroscopy(FT-IR) in micro ATR (attenuated totalreflectance) to identify the nature ofthe organic or inorganic materials;

• Pyrolysis mass coupled to gaschromatography-spettometry mass(Py-GC-MS) to identify the lacquersused in the decoration of the artifacts.

PYROLYSIS MASS results

ATTENDANT FIGURELacquer: The presence of glycerol.

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ANALISI MICRO-INVASIVE: FT-IR

FTIR results

DRUMS ELEMENTSWood: GLYCEROL

ATTENDANT FIGUREWood: PEGBlack lacquer: GLYCEROL, PEGRed lacquer: GLYCEROLEar glue: POLIVINILBUTIRALE

TOMB GUARDIANWood : PEGBlack lacquer : PEGBasement grey preparation: KAOLINBasement glue: EPOXY RESINBasement stuccoes: ACRILIC RESIN, KAOLIN

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EXPERIMENT: test of chinese lacquer - preparation

Preparation of the black carbon pigment.

Climatic chamber, made with 100 g of sodium dibasic heptahydrate(Na2HPO4.7H2O) in 100 ml of water.

Draft of chinese lacquer.

Lacquer specimen

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Specimen laurelwood with draftsof Chinese lacquer.

Use of carbonblack andcinnabar.

With the type A aging the degradation obtainedenter into the category of the deterioration ofChinese lacquer on wooden substrate.

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EXPERIMENT: test of chinese lacquer– aging and colorimetric measurements 20

Aging of type A, changes in temperature and relative humidity.

Simulation of the state of conservation of the object:

Type A: 42 cycles of 12 hours alternately placing the specimensin a climatic chamber (T 22-25 ° c and RH 65-95%) and in astove at 40 ° C.type B: specimens immersed in saline solution at 0.9% by 360hours at a temperature of 40 ° C.

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EXPERIMENT: test of chinese lacquer– aging and colorimetric measurements 21

Invecchiamento di tipo B, immersione in acqua.

campione ∆b

7 13,5

8 10,6

9 10,93

10 14.9

11 14.9

12 15,5

13 7,8

14 13,6

15 10,7

16 2,9

The aging of type B causeda strong yellowing of the lacquer,a clearing and aloss of surface gloss of the specimens.

Evident variations in the dimensions of(1mm)

Surfaces of lacquerchromatically altered.

Giannandrea G., Jervis A.V., Mercalli M., Ioele M., Priori G. 2008 – Pellicole pittoriche fortemente decoese su supporto cartaceo: sperimentazione di prodotti consolidanti.

22CONSOLIDANT: funori ed aquazol

«Funori usato spesso nel consolidamento delle statue in legno dipinte o finite a lacca quando il pigmento èpolveroso o sollevato a scaglie, e per far riaderire lo strato di rivestimento della lacca sulla superficie».da Carnazza P., Corak Rinesi K., Consolidamento Funori: adesivo di origine vegetale. Test di consolidamento dipittura su tela e consolidamento compatibile con le superfici opache su carta.

Aquazol 200 and 500 in solution with acetone and ethanol (1: 1) at concentrations of 2-2,5-3%.

Pure and purified Funori, in concentrations of 1, 2 and 3%, warmed.

Funori warmed. The funori dried after the purification

The procedure results in the loss of much of the initial material.

With an initial amount of 20 g of pure funori were obtained 2 g of purified dried funori.

EXPERIMENT: wooden specimens- colorimetry 23

A high differencebetween thecomponent SCI andSCE identifies a glossysurface.

Higher glossing inthe use of aquazol,higher with the 500.

Graphic shows how the difference between SCI and SCE increases after consolidation(Δ2) in the case of the specimens 7-8-9-10-11-12.

The funori not lead to any changes of glossing,and other color variations.

Both consolidating give morecohesion to the pigment.

This happens much more in thecase of funori applied by brush,because the material removedin the peeling test is on theorder of 1 mg.

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EXPERIMENT: wooden and coloured specimens- peeling test

- test di peeling

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Layers of lacquer treated with aquazol 200 and 500.

Layers of lacquer treated with funori purified and pure.

Funori purified and pure havethe same consolidatingpower. With nebulizationrequires two coats of funorito get the same consolidationof brush application.

Diagrams of the amount of pigment removed before and after consolidation.

Spolveratura, tassello di pulitura Spolveratura, tassello di pulitura

Dusting with the aid of soft brushes.

Improving the reading of the decoration.

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RESTORATION: Tomb guardian 25

Bonding of wood elements.

Bonding of wood elements.

Gluing wood elements (Sturgeon glue in aqueous solution 1:10)

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RESTORATION: Tomb guardian 26

Dusting.Bonding ear (bone glue in aqueous solution 1: 1)Gluing wood elements (sturgeon glue in aqueoussolution 1:10)

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RESTORATION: attendant 27

Dusting.

Gluing wood elements.Bonding ear.

Nebulisation funori (in 1% concentration) in two drafts.

Brush application of funori for all areas in which thewooden elements needed further strengthening.

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RESTORATION: attendant 28

Nebulizzation of funori Funori brush application

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RESTORATION: attendant 29

∆L ∆a ∆b ∆E

1 -4,1 0,2 -1,0 4,2

a -3,7 -0,3 -1,3 3,9

b -3,5 -0,5 -1,4 3,8

Colorimetric measurementspoints.

Colorimetric measurements made on three significant points have shown that:

the surface lightens slightly in all three cases (ΔL negative); (

there are no significant changes respect to the parameters a and b components red / green and yellow / blue).

ΔE within the parameters of acceptability slightly perceptible by the human eye.

Attendant figure, particular area of lacquer with strong surface lacquer

crack.Panel a: first consolidation;

panel b: after consolidation.