Natural and Synthetic Colorants in Early Twentieth Century Russian Art Problems of Transition and Coexistence
Evangelia A. Varella Aristotle University of Thessaloniki, Greece Introduction colour is colour thething without whichthe worldwould not bepossible Works of art, exhibited or stored, are susceptible to environmental factors, and alterations occur with the passage of time. To achieve a better and more effective preservation, the behaviour of all materials involved should be clarified. The complex artistic patrimony of early twentieth century Russian art is amalgamating occidental modernist tendencies with Byzantine expertise, Mongol aesthetic suggestions, and folkloric proposals. Monochromatic approaches are an outmost target, and hue is acquiring primordial importance, while brilliance and intensity are subjected to eager technical experimentations. Painting palettes of this controversial period represent an effective model for examining the influence of environmental factors and historical processes to the chromatic profile originally sought by the artist; and for confronting preservation problems created by the coexistence of traditional and modern synthetic colorants. The Role of Orthodox Iconography and Folkloric Art Colorants used in Russian icon painting are combining Byzantine tradition to Central Asian proposals, and Renaissance influences. Recipe collections compiled by local masters are already circulating in the 1400's, while antique and mediaeval treatises are systematically translated from the early seventeenth century on. Describing sophisticated lake preparations, recording on imported products, adjusting raw materials to indigenous possibilities, experimenting with the binding media – the manuscripts are clearly documenting of a long established craftsmanship.
Hand coloured folk prints and polychrome wooden artefacts representing all traditions blooming in the immense country, are in general following Orthodox aesthetic principles and technical expertise.
The mineral palette embraces crude and burnt Sienna and umbra earths; baryte, zinc white, lithopone, ceruse; natural cinnabar and vermilion, red lead; Pozzuoli earth, several ochres – haematite, red bole, caput mortuum, Pompei red, and later Mars products; orpiment, massicot, Naples yellow, antimony cinnabar; iron chlorides, silicates and phosphates; lazurite, ultramarine; and a great variety of natural and artificial copper compounds – carbonates e.g. azurite and malachite, chlorides e.g. atacamite, sulphates, nitrates, sulphocarbonates, arsenates, silicates e.g. Egyptian blue, phosphates e.g. pseudomalachite, acetates, e.g. verdigris. Although relatively rare, colouring lakes are traced as precious counterparts to inorganic pigments. Scale insects, red sandalwood, Brazil wood, madder, dyer’s bugloss, safflower; saffron, Persian berries, Indian yellow; tall cinquefoil; copper resinate; indigo or woad, and carbon black, are largely utilized in pure form or as ingredients of manifold composites. In the late nineteenth century low cost synthetic colouring compounds are straightforwardly introduced in the traditional painting palette. More often are encountered chrome yellow, and Prussian blue; alizarin, Hansa yellow, and fuchsine. Modernist Occidental Influences At the same time, Russian artist are taking modernist colour perception into serious consideration. Impressionist and symbolist European masters are by the turn of the century satisfactorily represented in the Shchukin and Morozov collections, while the First Golden Fleece Salon is leading to a solid implementation of expressionist and cubist concepts. At a scientific level, innovative circles are well acquainted with the approach developed in Colour Science, a fundamental treatise authored by W. Ostwald and translated in Russian in 1926. According to the essay, primary complementary colour pairs are red/sea green and yellow/ultramarine blue; furthermore orange/turquoise blue and purple/leaf green. Ivan Kliun is an enthusiastic adherent to the theory; while Boris and Maria Ender are revising the inherent assumptions by recapitulating the experiments on colour pursued in the Petrograd/Leningrad State Institute of Artistic Culture (GinKhuK).
Following in his line of thought the Theory of Colours conceived by J.W. von Goethe, while consenting to the Newtonian reality of tonal priorities, V. Kandinsky – later head of the Moscow Institute of Artistic Culture (InKhuK) – is indirectly reintroducing the ancient concept of tetrachromy, by parenting yellow to the triangle, and materializing blue in the circle. Colours and and Colours
Avant-Garde Colorants Individual avant garde paintings are accurately reflecting the contradictory historical processes in early twentieth century Russia. During the ancien régime industrial pigments are ordered to the main German, French and British suppliers; or locally produced by Central European and indigenous firms. By the turn of the century Dosekin is the most renowned relevant Russian company. In post revolutionary times materials are frequently deficient or mediocre, even though ingenious procedures are trying to meet the requirements. llow t and greater a rough hereflex colour; re
gether with e
thematerial we are working with are thecolorants, alone it with we createa new real world wepracticenot,apply in colours forasexample, t ofyellow but as aggregategreenson blue, an of of lesser or density uses artist an areand paints paints, never pu ofa even differs cobalt blue purefrom a passed blue th prism thequestion is legitimateit is if to doalto away combinations, infinite which distinguish cadmium ye from cobalt itviolet; if is permissible th todraw boundaries closedas as theyplaced byare thepain manufacturers s bad oured oured
ke pink kepink ramarine green, green,
alt and and alt
basic colourscolorants basic areand red, emeraldblack, blue;and white, andcobalt complementary ones citron rarely yellow, and madderlaultramarine and … dangerousis a pure huecobalt … i scarlet cinnabar redlead, purerather redcob lead, into or falling white fav English Saturnare and red madder, and cinnabar tonalities… green green, cobalt chrome is hard; ult madderlake red and blue smooth; emeraldgreen is a colour rald rald ite; ium; ilion, ilion, lt; and and lt; alt and alt
wecreatesurfaces hardened lava streamsof ofverm redcrepe black sky blue varnish,and cobalt yellowwith is prepared bleachedred umbra cadm and olive dark green umbra,orange andwith emecadmium pinkish browngreen; red cadmium, whumbra with and white blue and coba brown light umbra, with natural brownish cold cob umbra,blue naturalred lake with white Genuine and Current Chromatic Profile Russian avant gardeartists were often forced by circumstances to use low quality materials, while the compatibility of traditional and novel pigments was not always well comprehended. Particularly susceptible to injuries were paintings on paper, since cellulose undergoes natural ageing and decomposes, and can further interact with the actual paint layers, causing denaturation in components of both. The Stalinist era was drastically rejecting modernist attitudes, and numerous precious works were stocked up in an inefficient way. Consequently the authenticity of their appearance is rather questionable. The physicochemical research is proceeding by colorimetric and spectroscopic analysis of samples deriving from artificially aged experimental tables, prepared as watercolour and gouache layers on paper ground devoid of preparation. Respective binding media are gum Arabic or gum Arabic and chalk. Comparison is made with authentic paintings belonging to the Costakis Collection, State Museum for Contemporary Art, Thessaloniki. The colorants studied are red lead, orpiment and realgar, chrome yellow, verdigris, ultramarine blue, Prussian blue, Mars black; and combinations of orpiment and ultramarine blue, or chrome yellow and Prussian blue. Furthermore carmine lake, Brazil wood, madder and alizarin red, Indian yellow, indigo, van Dyck brown, carbon black; Hansa yellow, and fuchsine. Recent interventions are faced with the study of quinacridone magenta red, as well as phtalocyanine greens or blues. A systematic comparative review of all colorimetric, and spectroscopic data permits evaluating the colorants as to compatibility and stability towards extrinsic factors, and is proposing degradation routes at a molecular level, with the intention of contributing to the physicochemical elucidation and appropriate preservation of early twentieth century polychrome works of art. The experimental tables were subjected for a total time of three months to the influence of moist heat (90 oC, 60% relative humidity), and the influence of ultraviolet radiation (30 oC, 50% relative humidity). Colour measurements were performed during the accelerated ageing, and changes expressed using the colour space CIE 1976 (L *a*b*). The surface of both untreated and aged paint layers was as well microscopically observed. In order to determine the degree, in which chemical and molecular alterations are related to colour changes, micro Raman and FT infrared spectra of paint layers before and after ultraviolet exposure were recorded. 90οC, 60% Relative Humidity
60 60
50 50 chrome yellow orpiment red lead 40 40 prussian blue
∗ ∗ ultramarine ∗ ∗ ∗ ∗ 30 ∗ ∗ 30
∆Ε ∆Ε ∆Ε ∆Ε verdigris ∆Ε ∆Ε ∆Ε ∆Ε mars black 20 20
10 10
0 0 0 20 40 60 80 0 20 40 60 80 accelerated ageing, days accelerated ageing, days
ΔΕ * Changes of Watercolour and Gouache Paint Layers – Inorganic Colorants Ultraviolet Radiation, 30οC, 50% Relative Humidity
chrome yellow 40 prussian blue 30 orpiment ultramarine red lead verdigris
30 mars black ∗ ∗ 20 ∗ ∗ ∗ ∗ ∗ ∗ ∆Ε ∆Ε ∆Ε ∆Ε
∆Ε ∆Ε ∆Ε ∆Ε 20
10 10
0 0 0 20 40 60 80 0 20 40 60 80 accelerated ageing, days accelerated ageing, days
ΔΕ * Changes of Watercolour and Gouache Paint Layers– Inorganic Colorants Red Lead Pb 3O4 When exposed to ultraviolet radiation, paint layers displayed a remarkable decrease in brilliance, redness and yellowness. The alteration occurred in slow rate during the first days, had a sharp increase in the middle of the procedure, and was then led to a plateau. It is apparently due to partial transformation to orange yellow litharge – tetragonal PbO. Red Lead 90οC, 60% Relative Humidity
100 100 Pb O , watercolour Pb O , gouache 3 4 3 4 80 80
60 60
40 40 0 days 0 days 10 days Reflectance % Reflectance 20 % Reflectance 20 10 days 90 days 90 days 0 0
400 500 600 700 400 500 600 700 wavelength (nm) wavelength (nm)
∆ * L = 6.7 ∆L* = 8.0 ∆ * a = 3.5 ∆a* = 6.3 ∆ * b = 7.7 ∆b* = 9.8 ∆Ε * = 10.8 ∆Ε * = 14.1 Red Lead
Ultraviolet Radiation, 30οC, 50% Relative Humidity
100 100 Pb O , watercolour Pb O , gouache 3 4 3 4 80 80
60 60
40 40 0 days
Reflectance % Reflectance 30 days % Reflectance 0 days 20 90 days 20 30 days 90 days
0 0 400 500 600 700 400 500 600 700 wavelength (nm) wavelength (nm)
∆L* = 5.1 ∆L* = 10.3 ∆a* = 8.3 ∆a* = 16.5 ∆b* = 8.6 ∆b* = 13.1 ∆Ε * = 13.0 ∆Ε * = 23.5 Ultraviolet Radiation, 30οC, 50% Relative Humidity
Pb O watercolour Pb O gouache 3 4 3 4 * *
* * *
140 160 140 160
280 320 360
Intensity (a.u.) 90 days 90 days
20 days 20 days
0 days 0 days
200 400 600 200 400 600 -1 -1 Raman shift (cm ) Raman shift (cm )
Raman Spectra of Untreated and Artificially Aged Red Lead Paint Layers [676.4nm, 0.3mW; Litharge Peaks Indicated with an Asterisk] Orpiment As 2S3 Ultraviolet radiated layers displayed a gradual decrease in redness and yellowness, and an increase in brilliance.
The untreated pigment contains realgar – α As 4S4, which in the aged layer tends to yield pararealgar and arsenolite –
As 4O6. Fading of red realgar and simultaneous formation of yellow pararealgar and white arsenolite elucidates the changes in the initial hue. Sensitivity to ultraviolet radiation can be attributed to the biphasic state of the orpiment/realgar pigment, and its distribution in finer particles on the paper. Orpiment
90οC, 60% Relative Humidity
As S , watercolour As S , gouache 90 2 3 90 2 3
0 days 60 60 10 days
30 days 90 days 0 days
Reflectance % Reflectance 30 Reflectance % 30 10 days 30 days 90 days
0 0 400 500 600 700 400 500 600 700 wavelength (nm) wavelength (nm)
∆L* = 13.7 ∆L* = 5.6 ∆a* = 17.2 ∆a* = 8.6 ∆b* = 30.4 ∆b* = 11.8 ∆Ε * = 37.6 ∆Ε * = 15.7 Orpiment Ultraviolet Radiation, 30οC, 50% Relative Humidity
100 100 As S , watercolour As S , gouache 2 3 2 3 80 80
60 60
40 40 0 days 0 days 30 days 30 days % Reflectance
Reflectance % Reflectance 90 days 20 90 days 20
0 0 400 500 600 700 400 500 600 700 wavelength (nm) wavelength (nm)
∆L* = 9.3 ∆L* = 13.2 ∆a* = 15.1 ∆a* = 18.6 ∆b* = 18.9 ∆b* = 28.0 ∆Ε * = 26.0 ∆Ε * = 36.1 90οC, 60% Relative Humidity
As S , watercolour As S , gouache 2 3 2 3
90 days, As S 4 4 90 days 90 days, As S 2 3
Intensity (a.u.) 10 days 10 days
* 0 days 0 days * * * * * * * * * 150 225 300 375 450 150 225 300 375 450 -1 Raman shift (cm ) Raman shift (cm -1 )
Raman Spectra of Untreated and Artificially Aged Orpiment Paint Layers [676.4nm, 0.3mW; Orpiment Peaks Indicated with an Asterisk] Ultraviolet Radiation, 30οC, 50% Relative Humidity
As S , watercolour o As S , gouache o 2 3 2 3
o o
90 days o 90 days o o o o o a
p o p o a o p o o p p o p p p a p p p a p Intensity (a.u.)
0 days r 0 days r r r r rr r r r r r r r r r r r
150 225 300 375 150 225 300 375 -1 Raman shift (cm -1 ) Raman shift (cm )
Raman Spectra of Untreated and Artificially Aged Orpiment Paint Layers [676.4nm, 0.3mW; Realgar Peaks Indicated with an r/Pararealgar Peaks with a p/ Arsenolite Peaks with an a] Verdigris Cu(CH 3COO) 2.H 2O When watercolour layers are exposed to moist heat, tenorite
– CuO is formed. Reduction to cuprite – Cu 2O is stimulated by the reducing sugars of gum Arabic, and accelerated by ultraviolet radiation. Cuprite formation is taking place to a much smaller extent in the gouache layer; given that calcium is acting as an inhibitor in the reaction of copper with the carbohydrate units of gum Arabic, the presence of chalk could be credited with the relative stability of gouache. Verdigris 90οC, 60% Relative Humidity
40 verdigris, watercolour verdigris, gouache 50 35 90 oC, 60% RH 90 oC, 60% RH 30 40 25
20 30 0d 0d 15 25d 25d 20
Reflectance % Reflectance 10
5 10
0 0 400 500 600 700 400 500 600 700 wavelength (nm) wavelength (nm)
∆ * L = 17.9 ∆L* = 25.1 ∆ * a = 47.1 ∆a* = 42.8 ∆ * b = 15.8 ∆b* = 19.5 ∆Ε * = 52.8 ∆Ε * = 53.3 Verdigris Ultraviolet Radiation, 30οC, 50% Relative Humidity
50 verdigris, watercolour verdigris, gouache 30 40
0d 0d 20 5d 30 5d
20d 20d 90d 20 90d
Reflectance % Reflectance 10 10
0 0 400 500 600 700 400 500 600 700 wavelength (nm) wavelength (nm)
∆ * L = 0.3 ∆L* = 6.2 ∆ * a = 20.8 ∆a* = 14.8 ∆ * b = 18.4 ∆b* = 15.4 ∆Ε * = 27.8 ∆Ε * = 22.2 90οC, 60% Relative Humidity
verdigris, watercolour c verdigris, gouache
c
0 days 0 days
622 287 622 284 x 3 Intensity (a.u.) 331 25 days 334 25 days x 3
200 400 600 800 200 400 600 800 -1 -1 Raman shift (cm ) Raman shift (cm )
Raman Spectra of Untreated and Artificially Aged Verdigris Paint Layers [488nm, 0.25mW; Chalk Peaks Indicated with a c] Ultraviolet Radiation, 30οC, 50% Relative Humidity
verdigris watercolour verdigris gouache
c
c
* * * 90 days 90 days * Intensity(a.u.) * *
0 days 0 days
200 400 600 800 300 600 900 -1 Raman shift (cm -1 ) Raman shift (cm )
Raman Spectra of Untreated and Artificially Aged Verdigris Paint Layers [488nm, 0.25mW; Cuprite Peaks Indicated with an Asterisk; Chalk Peaks with a c] Prussian Blue Fe 4[Fe(CN) 6]3 Ultraviolet radiated layers demonstrated an initial raising, a subsequent decline, and a final restitution of brilliance values. Raman spectra recorded equally an initial shift of the cyan group to lower frequencies, followed by broadening.
Reduction to Berlin white – K2Fe[Fe(CN) 6] is probably taking place, stimulated by the reducing sugars of gum Arabic, and accelerated by ultraviolet radiation. Restitution could be based on the inhibition of any further reduction, as gum Arabic is decomposing. Berlin white is hence partly re oxidised to Prussian blue. Prussian Blue
Ultraviolet Radiation, 30οC, 50% Relative Humidity
O 10 Fe [Fe(CN) ] , gouache 12 UV, 30 C, 50%RH 4 6 3
10 8 0d 8 10d ∗ ∗ ∗ ∗ 6
50d
∆Ε ∆Ε ∆Ε ∆Ε 6
Reflectance % Reflectance 70d
4 90d watercolour 4 gouache 2 2 0 0 20 40 60 80 400 500 600 700 accelerated ageing, days wavelength (nm) Ultraviolet Radiation, 30οC, 50% Relative Humidity
gouache 2156 watercolour 2156
) 2154 2154 -1
2152 2152
Raman shift (cm 2094 2094
2092 2092
0 20 40 60 80 0 20 40 60 80 accelerated ageing, days accelerated ageing, days
Raman Shifts of the Cyanide Group Stretch Peaks in Prussian Blue During Accelerated Ageing [76.4nm, 0.1mW] 90οC, 60% Relative Humidity
24 24 alizarin carmine 20 brazilwood 20 indigo fuchsin 16 van Dyck brown Indian yellow 16 ∗ ∗ ∗ ∗ ∗ ∗ ∗ ∗ Hansa yellow ∆Ε ∆Ε ∆Ε ∆Ε ∆Ε ∆Ε ∆Ε ∆Ε magenta 12 12
phthaloblue phthalogreen 8 8
4 4
0 0 0 20 40 60 80 100 0 20 40 60 80 100 accelerated ageing, days accelerated ageing, days
ΔΕ * Changes of Watercolour and Gouache Paint Layers – Organic Colorants Ultraviolet Radiation, 30οC, 50% Relative Humidity
16 16
alizarin fuchsin Indian yellow 12 carmine 12 ∗ ∗ ∗ ∗ brazilwood Hansa yellow ∗ ∗ ∗ ∗ ∆Ε ∆Ε ∆Ε ∆Ε indigo magenta ∆Ε ∆Ε ∆Ε ∆Ε van Dyck brown phthaloblue 8 8 phthalogreen
4 4
0 0 0 20 40 60 80 100 0 20 40 60 80 100 accelerated ageing, days accelerated ageing, days
ΔΕ * Changes of Watercolour and Gouache Paint Layers – Organic Colorants Carmine Lake Colour alterations observed in ultraviolet radiated carmine layers are due to partial loss of the lake complex structure, as well as to crack formation on the surface. In the infrared spectra, a destabilization of the complex, in which the alum salt is linked through the carbonyl group, could be detected. Carmine Lake Carmine Lake
90οC, 60% Relative Humidity
0 0
-4 watercolour -4 gouache
-8 -8 R% R R %
∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ 5d 5d -12 90d 90d -12
-16 -16
-20 400 500 600 700 400 500 600 700 wavelength (nm) wavelength (nm)
∆L* = 2.3 ∆L* = 1.5 ∆a* = 7.2 ∆a* = 7.2 ∆b* = 3.8 ∆b* = 3.9 ∆Ε * = 8.5 ∆Ε * = 8.3 Carmine Lake Ultraviolet Radiation, 30οC, 50% Relative Humidity
0 watercolour 6 gouache 45d 5 90d -2
4 R % R R % R
∆ ∆ ∆ ∆ -4 ∆ ∆ ∆ ∆ 45d 3 90d -6 2
-8 1 400 500 600 700 400 500 600 700 wavelength (nm) wavelength (nm)
∆L* = 2.6 ∆L* = 7.9 ∆a* = 4.8 ∆a* = 8.1 ∆b* = 3.5 ∆b* = 8.8 ∆Ε * = 6.5 ∆Ε * = 14.4 Ultraviolet Radiation, 30οC, 50% Relative Humidity
carmine, watercolour 2 1,0
1 Kubelka-Munk units Kubelka-Munk
0 4000 3500 3000 2500 2000 1500 1000
wavenumber,cm -1 0d 0,5 90 d Kubelka-Munk units Kubelka-Munk
0,0 2100 1800 1500 1200 900
7 carmine, gouache 6 5
4 4
3
2
1 Kubelka-Munk units Kubelka-Munk
0 4000 3500 3000 2500 2000 1500 1000 0d wavenumber,cm -1
2 90d Kubelka-Munk units Kubelka-Munk
0 2100 1800 1500 1200 900
wavenumber,cm -1
FT IR Reflectance Spectra of Carmine Lake Layers before and after Ageing Brazil Wood Under ultraviolet radiation, main parameter contributing to the total colour difference is L *, confirming that the fugitive behaviour of the dye is playing the predominant role in colour change. The infrared spectra are implying that even a 350 nm radiation is sufficient for inducing oxidation of phenolic brazilin to aromatic carboxylic brazilein. A small rise in brilliance under the effect of moist heat is pointing at a dye loss on the paper substrate. Brazil Wood
Ultraviolet Radiation, 30οC, 50% Relative Humidity
20 28 brazilwood, watercolour brazilwood, gouache 18 24
16 20 0 days 0 days 90 days 14 90 days 16
12 12 Reflectance % Reflectance
10 % Reflectance 8 8 4 6 400 500 600 700 0 400 500 600 700 wavelength (nm) wavelength (nm)
∆L* = 6.4 ∆L* = 11.1 ∆a* = 0.7 ∆a* = 0.7 ∆b* = 0.8 ∆b* = 0.5 ∆Ε * = 6.5 ∆Ε * = 11.1 Ultraviolet Radiation, 30οC, 50% Relative Humidity
16 16 watercolour 12
8 12 4 Kubelka-Munk units Kubelka-Munk 0 0d 4000 3500 3000 2500 2000 1500 1000 8 wavenumber,cm -1 90 d
4 Kubelka-Munk units 0
2000 1750 1500 1250 1000 750
16 16
gouache 12
8
12 4 Kubelka-Munk units Kubelka-Munk 0
4000 3500 3000 2500 2000 1500 1000 8 0d wavenumber,cm -1
90d
4 Kubelka-Munk units Kubelka-Munk
0
2000 1500 1000
wavenumber,cm -1
FT IR Reflectance Spectra of Brazil Wood Layers before and after Ageing Alizarin Colour fading, observed in alizarin layers subjected to moist heat ageing, is due to alterations in the intramolecular hydrogen bonding between the carbonyl and the hydroxyl group, as well as to high crack formation on the surface. Alizarine 90οC, 60% Relative Humidity
2 2 watercolour gouache
1 0
0 -2 R% R % R
∆ ∆ ∆ ∆ -1 ∆ ∆ ∆ ∆ 10 days -4 -2 90 days 10days 90days -3 -6
-4 400 500 600 700 400 500 600 700 wavelength (nm) wavelength (nm)
∆L* = 0.3 ∆L* = 3.6 ∆a* = 6.2 ∆a* = 7.7 ∆b* = 5.2 ∆b* = 10.2 ∆Ε * = 8.0 ∆Ε * = 13.3 90οC, 60% Relative Humidity
14 alizarin 14 alizarin, watercolour 14 alizarin, gouache 12 12 12
10 10 0d 0d 10 0d 8 90d 8 90d 8 90d
6 6 6
4 4 4
2 2 2 Kubelka-Munk units Kubelka-Munk 0 0 0 4000 3500 3000 2500 2000 1500 1000 4000 3500 3000 2500 2000 1500 1000 4000 3500 3000 2500 2000 1500 1000 -1 wavenumber,cm wavenumber,cm -1 wavenumber,cm -1
FT IR Reflectance Spectra of Alizarin Layers before and after Ageing Indian Yellow The colorant was fairly susceptible to moist heat ageing. On the surface of both watercolour and gouache layers, formation of dark areas is explaining the decrease of all colour parameters. The physical nature of the chromatic alteration – deterioration of the smooth surface, changes in particle aggregation, crack formation – was proven by the lack of differentiation in the infrared spectra. Indian Yellow
90οC, 60% Relative Humidity
watercolour 30
20 0 days 30 days 90 days
Reflectance % Reflectance 10
0 400 500 600 700 wavelength (nm)
∆L* = 3.0 ∆a* = 5.6 ∆b* = 4.8 ∆Ε * = 8.0 Hansa yellow PY3 Under high temperature and humidity, important decreases in both brilliance and yellowness are observed. A warm and moist environment is causing extended crack formation, responsible for reducing reflectance values. Lessening of yellowness may be due to gradual sublimation of the colouring agent. Hansa Yellow
90οC, 60% Relative Humidity
100 watercolour 80
60
40 0 days 45 days Reflectance % Reflectance 20 90 days
0
400 500 600 700 wavelength (nm)
∆L* = 8.7 ∆a* = 0.4 ∆b* = 19.2 ∆Ε * = 21.1 Fuchsine As a solid, fuchsine forms green yellow crystals, turning to purple when dissolved in water. Exposure in ultraviolet light caused an immediate substantial decrease of b values in both watercolour and gouache layers. Infrared spectra of ultraviolet radiated layers recorded amino group shifts due to the intramolecular charge transfer caused by ultraviolet excitation. An increase in brilliance, observed after forty days of ageing, is justified on the basis of the more fugitive dye monomer. On the paint layer surface the paper was at occasions totally revealed. The increase in brilliance and yellowness is related to the formation of bright yellow areas, probably due to aggregation of dye crystallites and the improvement of their reflecting surface. Further ageing induced intense crack formation, and subsequent re darkening of the surface. Fuchsine
Ultraviolet radiation, 30οC, 50% Relative Humidity
20 fuchsin, watercolour 24 fuchsin, gouache
16 20 0 days 0 days 16 12 90 days 90 days
12 8 8 Reflectance % Reflectance Reflectance % Reflectance 4 4
0 0 400 500 600 700 400 500 600 700 wavelength (nm) wavelength (nm)
∆L* = 4.5 ∆L* = 3.2 ∆a* = 0.4 ∆a* = 0.3 ∆b* = 14.1 ∆b* = 14.0 ∆Ε * = 14.8 ∆Ε * = 14.4 Ultraviolet Radiation, 30οC, 50% Relative Humidity
fuchsin, watercolour fuchsin, gouache
12 12 0d 0d 90d 90d
6 6 Kubelka-Munk units Kubelka-Munk
0 0
4000 3500 3000 2500 2000 1500 1000 4000 3500 3000 2500 2000 1500 1000 -1 wavenumber,cm wavenumber,cm -1
FT IR Reflectance Spectra of Fuchsine Layers before and after Ageing In general, colouring agents – with the exception of alizarin, Indian yellow, and Hansa yellow – were stronger influenced by ultraviolet light than by high temperature combined to humidity. Red lead, orpiment, verdigris, Prussian blue, carmine lake, and Brazil wood proved more sensitive; while chrome yellow, ultramarine blue – 3Na 2O.3Al 2O3.6SiO 2.Na 2S, alizarin, Indian yellow, Hansa yellow, and fuchsine exhibited a better stability.
Mars black – Fe 3O4, indigo, van Dyck brown; quinacridone magenta red PR122, and phtalocyanine green or blue were hardly affected. quinacridone magenta red PR122
phtalocyanine green and blue The higher light sensitivity of gouache layers might be attributed to the lower concentration and smaller aggregation of pigment particles, since they are interpolating with chalk entities. The comparative review of all data permits regenerating certain features of the chromatic profile, as originally created by the artist; is evaluating the colorants as to compatibility and stability towards extrinsic factors; and is proposing degradation routes at a molecular level. The experimental tables were subjected to the ageing tests in a Voetsch VC0018 climatic chamber. They were exposed to Philips Cleo 20W fluorescence tubes, which emit highly concentrated ultraviolet radiation in the 300 400 nm range, peaking at 350nm. The samples were placed at a distance of 2 cm from the radiation source. A Miniscan XE Plus spectrophotometer (HunterLab) was used for colour measurements during the accelerated ageing. The surface was studied under an Olympus Bx60 optical microscope with a JVC TK C1381 camera and Leica MW Software. The total colour difference ∆Ε * between the sample prior to light exposure and at each measurement during the ageing was calculated according to the equation: ∆Ε *= {(∆L*)2 + (∆a*)2 + (∆b*)2 }1/2 . Micro Raman spectra were recorded using a triple grating spectrometer (Dilor XY) equipped with a CCD liquid nitrogen cooled detector system. The blue (488 nm) line of an Ar ion laser and the red line (676.4 nm) of a Kr ion laser were used for excitation and the spectral resolution of the system was ~3 cm 1. The laser was focused on the sample through the system’s microscope equipped with a standard objective lens 100x. The relevant power was kept at 0.1 0.3mW, in order to avoid damaging the underlying samples. FT Infrared spectra were recorded on a Perkin Elmer Spectrum GX II spectrometer equipped with a MCT detector. The spectra were collected in reflectance mode in the range of 4000 700 cm 1, with a resolution of 4 cm 1, an aperture of 100x100 m, and 300 scans per measurement. Four spectra from different areas of each sample were recorded and the average spectrum was calculated. As a conclusion, colour alterations due to environmental factors have been elucidated; and degradation routes have been proposed, with the intention of assisting museum conservators in every concrete case related to the broad spectrum of pigments, either actually studied or belonging to chemically related compound groups. Physicochemical Investigation of Avant-GardePaintings The survey encompasses a series of samples taken from twenty two watercolour and gouache paintings on paper, belonging to the Costakis Collection in the State Museum for Contemporary Art, Thessaloniki. In an attempt to represent a significant number of art historical tendencies and theoretical concepts, as well as to consider a large variety of hues, the selection focused on Boris, Maria, Xenia and Yuri Ender, Ivan Kliun, Ivan Kudriashev, Salomon Nikritin, Konstantin Vialov, Alexander Volkov, and possibly Liubov Popova. Artist Inv. Number Number Colour of Samples of Samples B. Ender C473 3 pale green/dark green/blue
M. Ender C429/AB625 2 scarlet red/dark red
X. Ender 173.80/Α 1 black
175.80 1 reddish violet
392.81 1 green
C453.549 1 blue
C454 3 red/pale green/blue
34.78 3 brownish red/scarlet red/blue
Y. Ender C259 1 azure
C472 2 reddish green/leaf green
I. Kliun AB306/802.79 1 bluish purple
AB326 1 green
C555 1 fuchsia red
C559 1 dark bluish purple
C446 1 brown
I. Kudriashev AB416/C501 1 green
AB739 1 black/white
S. Nikritin 8 C9 2 red/black [ink]
9 C219 1 grey
K. Vialov 227.80 3 green/blue/black
A. Volkov 281 14 red/pink/orange/greenish yellow/citron yellow/dark yellow/pale green/dark green/pale azure/azure/dark azure/turquoise/ultramarine blue/dark blue [L. Popova] C717 9 red/greenish pink/pale green/leaf green/dark green/ azure/turquoise/ultramarine blue/dark blue
List of Paintings [ Costakis Collection, State Museum for Contemporary Art, Thessaloniki] Colouring compounds identified include chalk, zinc white, vermilion, red ochre/Mars red, red lead; carmine lake, madder/alizarin; yellow ochre/Mars yellow, chrome yellow, and zinc yellow; emerald green, ultramarine blue, Prussian blue, and carbon black; as well as various well established or unconfirmed mixtures. Zinc white acts as a prevailing white colorant, being at the same time an excellent gouache filler, along with chalk. Chalk Zinc Vermilion Red Ochre/ Red Lead Carmine Madder/ White Mars Red Alizarin B. Ender
M. Ender *
X. Ender * *
Y. Ender *
I. Kliun * * * *
I. Kudriashev *
S. Nikritin * * *
K. Vialov
A. Volkov * * *
[L. Popova] * *
Yellow Ochre/ Chrome Zink Chrome Emerald Ultramarine Prussian Carbon Mars Yellow Yellow Yellow Green Green Blue Blue Black B. Ender * *
M. Ender
X. Ender *a * * *
Y. Ender * * *
I. Kliun * * * * *
I. Kudriashev * * *
S. Nikritin *
K. Vialov * * *a
A. Volkov * * * *
[L. Popova] *a *
Distribution of Colorants by Painter [Sporadic Grains Indicated with an a]
Vermilion HgS Red Lead Pb 3O4
254
343 SAMPLE
285 Intensity(a.u) 122
Intensity(a.u.) 549 152 391 313 224 STANDARD
200 250 300 350 400 200 300 400 500 -1 -1 Raman shift (cm ) Raman shift (cm )
M. Ender, Inv.Nr. C429/AB625 A. Volkov, Inv.Nr. 281
Raman Spectra of Samples Identified as Vermilion and Red Lead [676.4nm, 0.3mW] Mars Red Fe 2O3
1087 293 293
227 226
1050 1100 1150 Raman shift (cm -1 ) 410 411
613 Intensity (a.u.) Intensity (a.u.) 614
200 300 400 500 600 700 200a 300 400 500 600 700 b -1 Raman shift (cm -1 ) Raman shift (cm )
I. Kliun, Inv.Nr. C559 S. Nikritin, Inv.Nr. 8 C9
Raman Spectra of Samples Identified as Mars Red [676.4nm, 0.3mW] Alizarin
1472 1299 1326
1355 1639 Intensity(a.u)
1100 1200 1300 1400 1500 1600 1700 -1 Raman shift (cm )
X. Ender, Inv. Nr. C454
Raman and FT IR Reflectance Spectra of a Sample Identified as Alizarin [488nm, 0.3mW]
Chrome Yellow PbCrO 4 Emerald Green Cu(C 2H3O2)2.3Cu(AsO 2)2
358 840 153 377 338 215 400 325 STANDARD 120 243
173 539
SAMPLE 293 370 432 324 948 760 1087 835 Intensity (a.u.) Intensity(a.u)
282
SAMPLE
100 200 300 400 500 600 700 800 900 1000 300 400 700 800 900 10001100 Raman shift (cm -1 ) Raman shift (cm -1 ) A. Volkov, Inv.Nr. 281 B. Ender, Inv.Nr. C473
Raman Spectra of Samples Identified as Chrome Yellow and Emerald Green [676.4nm, 0.3mW] Ultramarine Blue 3Na 2O.3Al 2O3.6SiO 2.Na 2S
547 545
1096 805 584 263 Intensity (a.u.) Intensity (a.u.)
584 1091
200 400 600 800 1000 450 600 750 900 1050 -1 Raman shift (cm -1 ) Raman shift (cm )
K. Vialov, Inv.Nr. 227.80 A. Volkov, Inv.Nr. 281
Raman Spectra of Samples Identified as U ltramarine Blue [676.4nm, 0.3mW] Prussian Blue Fe 4[Fe(CN) 6]3
2154 STANDARD 2093 2155 2093
SAMPLE Intensity(a.u) Intensity (a.u)
SAMPLE
2050 2100 2150 2200 2050 2100 2150 2200 -1 -1 Raman shift (cm ) Raman shift (cm )
B. Ender, Inv.Nr. C473 X. Ender, Inv.Nr. C454
Raman Spectra of Samples Identified as Prussian Blue [676.4nm, 0.3mW] As a rule, a mixture of blue and yellow pigments – usually chrome yellow and Prussian blue – is credited with the creation of green areas. In several cases zinc yellow is added to Prussian blue, or yellow ochre to ultramarine blue. Purple tints are habitually due to ultramarine blue mixed with vermilion, or with carmine lake and carbon black. Carbon black is yielding brown with Mars red, and grey with zinc white. Red Orange Green Purple Brown
X. Ender Mars yellow, vermilion, chrome yellow, Prussian blue Prussian blue
Y. Ender zinc yellow, Prussian blue
zinc yellow, ultramarine, vermilion I. Kliun chrome yellow, red ochre, red ochre, Prussian blue ultramarine ultramarine, carbon black carmine lake, ultramarine, zinc white I. Kudriashev yellow ochre, ultramarine
K. Vialov yellow ochre, ultramarine
yellow ochre, Prussian blue
A. Volkov red lead, chrome yellow, chrome yellow Prussian blue
chrome yellow, Prussian blue
[L. Popova] red lead, yellow ochre, madder lake carbon black
Distribution of Composite Colorants by Painter Green Tints
c
ZnCrO 870 c 4
p
774 p 940 891 Intensity (a.u.) Intensity (a.u) 346
250 500 750 2100 2200 150 300 450 600 750 900 1050 -1 -1 Raman shift (cm ) Raman shift (cm )
I. Kliun, Inv.Nr. AB326 Y. Ender, Inv.Nr. C472
Raman Spectra of a Sample Identified as Chrome Green [Chrome Yellow Peaks Indicated with a c, Prussian Blue Peaks with a p]; and of the Yellow Component of a Green Sample, Identified as Chrome Zinc Yellow [676.4nm, 0.3mW]
Purple Tints
1395 1595 545 1325
1094 257 580 1231 1491 1659
1259 254 293
225
Intensity(a.u.) Intensity (a.u.) 411 344 284 611 498 200 300 400 Raman shift (cm -1 )
400 800 1200 1200 1300 1400 1500 1600
Raman shift (cm -1 ) Raman shift (cm -1 )
I. Kliun, Inv.Nr. C555 I. Kliun, Inv.Nr. AB306 802.79
Raman Spectra of a Sample Identified as Vermillion and Prussian Blue; and of the Red Component of a Purple Sample, Identified as a Mixture of Carmine and Carbon Black [676.4 nm, 0.3 mW]
Brown and Grey Tints
1586 98 293
225 1371
1340 437
1600
411 Intensity (a.u.) Intensity (a.u.) 611 498
200 400 600 1200 1400 1600 80 100 120 420 440 460 1300 1400 1500 1600 1700 Raman shift (cm -1 ) Raman shift (cm -1 ) Raman shift (cm -1 )
I. Kliun, Inv.Nr. C446 I. Kudriashev, Inv.Nr. AB739
Raman Spectra of a Sample Identified as Mars Red and Carbon Black; and of a Sample Identified as Zinc White and Carbon Black [676.4 nm, 0.3 mW]
Systematization, Valorisation & Dissemination of e- Learning Courses in Conservation Science Lifelong Learning Programme/Erasmus/Virtual Campus
Partners: Aristotle University of Thessaloniki (coordinator) University of Avignon & the Vaucluse Cà Foscari University of Venice Rey Juan Carlos University at Madrid aStyle Linguistic Competence, Vienna S. Mohammed ben Abdellah University of Fez http://econsc.chem.auth.gr/VirtualCampus The project addresses virtual mobility in the field of material cultural heritage preservation by organizing specialized course units on conservation science, as well as seminars on concrete diagnostic or safeguarding problems. It is conceived as a virtual campus offering joint curricula in both lecturing and practicing laboratory work, and enhancing the birth of a common language in problem solving. Contact Persons: Evangelia A. Varella (Greece) [email protected] Cathy Vielliescazes (France) cathy.vieillescazes@univ avignon.fr Gino Paolucci (Italy) [email protected] Mariano Fajardo (Spain) [email protected] Rachid Benslimane (Morocco) [email protected] Water Zeller (administrator for linguistic issues) [email protected] Ioannis Kozaris (ICT administrator) [email protected] 3rd Summer School on Conservation Science
July 19 31, 2008
Thessaloniki, Greece
http://culture.chem.auth.gr/SummerSchool2009 (available from 15 th of December 2008)