Comparison of the fading and surface deterioration of red lake pigments in six paintings by
Vincent van Gogh with artificially aged paint reconstructions
Aviva Burnstock* and Ibby Lanfear
Department of Conservation and Technology
Courtauld Institute of Art
Somerset House
London WC2R 0RN
United Kingdom
E-mail: aviva.burnstock@courtauld.ac.uk
Klaas Jan van den Berg, Leslie Carlyle and Mark Clarke
Instituut Collectie Nederland (ICN),
Gabriel Metsustraat 8
Postbus 76709
1070 KA Amsterdam
The Netherlands
E-mail: klaas.jan.vd.berg@icn.nl; lesley.carlyle@icn.nl; mark@clericus.org
Ella Hendriks
Van Gogh Museum
Postbus 75366
1070 AJ Amsterdam
The Netherlands
E-mail: hendriks@vangoghmuseum.nl
Jo Kirby
Scientific Department
National Gallery
Trafalgar Square
London WC2N 5DN
United Kingdom
E-mail: jo.kirby@ng-london.org.uk
*Author to whom correspondence should be addressed
Abstract
The surface deterioration and fading of red lake paints in six paintings by Vincent van Gogh,
painted in Antwerp and Paris between 1885 and 1888, are compared with changes in artificially
aged red lake paint reconstructions. Light-ageing of the paints indicated that lakes made from
madder, laboratory-prepared Kopp’s purpurin and cochineal on alumina faded more slowly than
those made from brazilwood, eosin and cochineal on a tin-containing substrate. ‘Spotting’ of
Kopp’s purpurin- and redwoodcontaining paints, and jelly-like lumps in paints containing
brazilwood, were observed in both paintings and aged samples. Characteristic cracking occurred
in lake paints containing starch.
Keywords
paintings, red lake pigments, Vincent van Gogh, fading, light-ageing, paint reconstructions
Introduction
The fading and discolouration of red lake pigments used by Vincent van Gogh has been
documented in several technical studies of his paintings from the Arles, Auvers-sur-Oise and StRémy periods (Peres 1991, Peres et al. 1991, Bang 1991, Cadorin 1991, Hofenk De Graaf et al.
1991, Rioux 1999a, b, Hendriks and Van Tilborgh 2001, Hendriks 2005). This paper considers
the fading and surface deterioration of red lake paints found in six Antwerp and Paris works by
van Gogh (between 1885 and 1888), compared with paint reconstructions made using 19th
century recipes. The red lake paints in samples taken from these paintings are characterized in
full elsewhere.1 The comparisons were made visually, using light microscopy and scanning
electron microscopy. The study also aimed to provide criteria for evaluating the success of the
artificially aged reconstructions in replicating ageing evident in the paintings. It is clear that the
red lakes were a critical pigment group on van Gogh’s palette, playing a key role in creating the
intended colour schemes and emotional impact of his paintings. From Antwerp Vincent wrote:
‘…and although the quality of colour is not everything in a picture, it is what gives it life’.2
The artist’s concern for the stability of his colours is demonstrated by frequent references to this
topic in his letters to his brother Theo, from his time in Holland to the year of his death in 1890.3,4
Though his correspondence reveals acute awareness of the standard and consistency of his
colours, the painter’s lack of financial means necessitated his use of lower-quality products that
have often affected the permanency of his work.
Context for the present study: paint reconstructions
The preparation and artificial ageing of 19th century red lake paint reconstructions was
undertaken as part of a wider investigation of the materials and techniques used by van Gogh, in
collaboration with the Van Gogh Museum, the Institute for Cultural Heritage, and the Shell
Research and Technology Centre, Amsterdam, the Courtauld Institute of Art, and the National
Gallery, London. In a workshop coordinated by Kirby (Kirby 2005), 17 red lake pigments were
made using selected 19th century French, English or German recipes, based on the analytical
results of van Bommel et al.1 Lakes were made from cochineal and brazilwood dyestuffs on
aluminium- and tin-containing substrates, including one tin-containing cochineal lake with a
starch extender. Lakes from eosin, madder, laboratory-prepared ‘Kopp’s purpurin’ (containing
largely pseudopurpurin and purpurin, little alizarin), and one containing both brazilwood and
madder dyestuffs were prepared on aluminium-containing substrates. The pigment preparation
and documentary sources used are discussed elsewhere (Kirby 2005). In a workshop coordinated
by Carlyle (Carlyle 2005), a set of paints with 11 of the lakes were prepared with water-washed
linseed oil (LW). Each paint was also mixed with lead white paint, zinc white paint, Megilp or
chalk. Five other sets of paints were prepared: one was made with lead treated oil and another
with B72 binder (to form a stable and inert control). The three remaining sets were prepared with
LW oil as follows: a mixture of lake pigments, a standard mixture of three pigments (ultramarine,
vermilion, emerald green) plus each lake, and a set with dry powdered wheat starch added prior
to grinding. Carmine lake was prepared with lead treated oil only. The paints were prepared as
stiff as possible while remaining workable. Paints were left to dry for five weeks at low light
levels, a compromise to limit dark-induced yellowing while avoiding premature fading. Most
paints were then touch-dry; only the samples with Megilp were still sticky.
Examination of paintings
The six paintings selected for this study were selected as representative for the different types of
red lake paint used by the artist. These works had been stored and displayed in an uncontrolled
environment until the opening of the Van Gogh Museum in 1973: Head of an Old Woman, midDecember 1885 to mid-January 1886; Bottle with Peonies and Blue Delphiniums, June–mid-July
1886; Glass with Yellow Roses, late June to mid-July 1886 (Figure 1); Flame Nettle in a
Flowerpot, late June to mid-July 1886; Agostina Segatori in the Café du Tambourin, January–
March 1887 (Figure 2); Portrait of Lucien-Etienne Martin, November 1887 to mid-February
1888 (Figure 3). The pictures were examined using the light microscope to characterize the
application of red lake-containing paints, associated surface deterioration and visual evidence for
fading. In each case, evidence of pigment mixtures and layer structure was available from paint
cross sections, prepared as part of the van Gogh project.1
Experimental
Materials
Cochineal, insects (#36040); Madder, ground root (#37200); Brazilwood (#36150); KremerPigmente, Alchstetten. Eosin, Meister Lucius & Brüning, ICN-reference collection, inv. nr. 4328.
Linseed oil from organic linseeds (Molart 1999 stock) was washed (LW oil) with Millipore water
for six weeks, changing water twice weekly and shaking daily. Lead-treated (LD) oil was
prepared by mixing lead(II) oxide (Fisher) with freshly pressed linseed oil in a 1:2 ratio, shaking
daily for eight days, then decanted and sealed until used. LW oil density: 0.90; LD oil density:
0.92. Megilp was prepared by mixing equal amounts of mastic varnish (2:1 turpentine:resin), and
lead-treated oil (left on PbO, 19 days).
Figure 1. Glass with Yellow Roses, Van Gogh Museum, Amsterdam (Vincent van Gogh
Foundation)
Figure 2. Agostina Segatori in the Café du Tambourin, Van Gogh Museum, Amsterdam (Vincent
van Gogh Foundation)
Figure 3. Portrait of Lucien-Etienne Martin, Van Gogh Museum, Amsterdam (Vincent van Gogh
Foundation)
Lead white pigment was ground in LW on an Exact laboratory three-roller mill at Old Holland
Classic Oil Paints (50 g lead white:10 ml LW). The control and zinc white paints were hand
ground (40 g ZnO:14 ml LW). Emerald green was from the Tate Gallery’s Cornelissen’s archive
(1910–1950); other pigments were from Kremer-Pigmente. Wheat starch was from Lineco,
Holyoke, MA. Other chemicals were commercially available and used as obtained. The paints
were applied to white Teflon sheets or Melinex with a draw-down bar (clearance 25 μm), a brush,
or palette knife. A set on commercially prepared artists’ board was prepared using both brush and
palette knife.
Light-ageing and colour measurement
Paints were light aged at 25 °C and 60 per cent relative humidity at SRAL. Illumination was
provided by 36 W Philips colour 96 fluorescent lamps, measured output 10,000 lux at the sample
surface. Total ageing time 2850 h = 49 years of exhibition in recommended museum conditions,
200 lux, 8 h a day, assuming reciprocity, or more than 64 years of light-ageing in the van Gogh
museum (maximum 150 lux). Colour changes for the samples on Teflon were recorded using a
Minolta CR221 colour meter at intervals during ageing; observer 2°, illuminant D65, specular
component excluded. Measurements were made using Melinex templates, allowing colour
readings of the samples at the same spot every time. Data consist of the average of three
measurements on three spots, converted to CIE 1976 L*a*b* space and processed in Microsoft
Excel.
Results of light-ageing
The study suggests that cochineal and madder lake paints are more stable than
brazilwood/madder combinations, and that brazilwood and eosin lakes are the most fugitive.
Lakes with a tin-containing substrate are usually less stable than those on an aluminiumcontaining substrate. Both densely pigmented and thickly applied paints fade relatively slowly,
whereas all paints fade faster when mixed with white. The relative rates of fading of the paints
follow the findings of Saunders and Kirby (1994), who examined lakes based on recipes from
earlier periods.
Table 1 shows the changes in redness (a*) and colour difference (ΔE) during light-ageing of the
base paints and mixtures with lead white. The curves demonstrate the relative stability of madder
and the cochineal samples, although
Table 1. Colour changes for red lake base paints during light-ageing: (a, b) base paints; (c, d)
mixed with lead white
the cochineal samples on tin-containing substrates (C3 and C4; cochineal/Sn) faded more rapidly
than those on aluminium-containing substrates (cochineal/ Al). The cochineals on alumina were
less stable than madder lakes with the same substrate. Cochineal on alumina alone (C1) was more
fugitive than C2, containing also a small amount of tin. Madder (M1) was marginally more stable
than the lake made from ‘Kopp’s purpurin’ (M2). This may be due to the higher proportion of
alizarin in M1: alizarin is very stable, although its stability relative to that of pseudopurpurin
(M2) is unclear. In the mixed lakes, the more fugitive lake generally determines the rate of
fading. Table 2 illustrates the rates of fading of pigments bound in Paraloid B72. The relative
instability of eosin, brazilwood and the brazilwood/madder combinations is evident; similarly,
that of cochineal/Sn relative to the other cochineals and madder-type lakes. The brazilwood/Sn
lake discoloured rapidly, turning brown even in the dark. During the initial stages of fading,
many lake paints become less yellow (decreasing values of b*) because of bleaching of the
medium. Brazilwood paints, however, increase in yellowness due to the formation of yellow
intermediates during the fading process (Saunders and Kirby 1994). Table 3, illustrating ageing
curves for brazilwood/Al and eosin lakes, suggests that a yellowish component may develop at a
late stage as eosin fades, but this needs further investigation. It is difficult to compare the
stability of the lakes solely based on changes in ΔE and a* with time colour changes depend on
several factors (Saunders and Kirby1994). The pigment dyestuff concentration plays an important
role: that of the cochineal/Al pigments was very high, thus their relative stability could be best
assessed when the lakes were combined with additives such as starch, chalk or white pigments.
Fading is also influenced by transparency and layer thickness; colour was retained in thick layers
of transparent base paints (Figure 4). In a pilot study, some samples were artificially aged under
ultraviolet (UV)- filtered light. The results showed that the rate of fading was lower than for
samples aged in light with UV present. The UV filtering provided only limited
Table 2. Colour changes for six red lake paints in Paraloid B72 during light-ageing: (a) a* vs.
time; (b) ΔE vs. time
During the initial stages of fading, many lake paints become less yellow (decreasing values of b*)
because of bleaching of the medium. Brazilwood paints, however, increase in yellowness due to
the formation of yellow intermediates during the fading process (Saunders and Kirby 1994).
Table 3, illustrating ageing curves for brazilwood/Al and eosin lakes, suggests that a yellowish
component may develop at a late stage as eosin fades, but this needs further investigation. It is
difficult to compare the stability of the lakes solely based on changes in ΔE and a* with time
colour changes depend on several factors (Saunders and Kirby 1994). The pigment dyestuff
concentration plays an important role: that of the cochineal/Al pigments was very high, thus their
relative stability could be best assessed when the lakes were combined with additives such as
starch, chalk or white pigments. Fading is also influenced by transparency and layer thickness;
colour was retained in thick layers of transparent base paints (Figure 4). In a pilot study, some
samples were artificially aged under ultraviolet (UV)- filtered light. The results showed that the
rate of fading was lower than for samples aged in light with UV present. The UV filtering
provided only limited
Figure 4. Influence of thickness of transparent lake paints on fading; a, b) B2LW, before and
after ageing; c, d) EOLW, before and after ageing
Table 3. Colour changes for (a) brazilwood on alumina, 0–2850 h and (b) eosin lake paints, 0–
1000 h
protection; eosin paint (EOLW) still showed considerable fading after lightageing equivalent to
11 years.
Results of examination of paintings
Characteristic fading and surface deterioration of the red lake paints were identified in the six
paintings included in this study. Those that contained lake made from brazilwood, or in paintings,
redwood lake mixed with another lake showed significant changes. For Head of an Old Woman,
fading is most pronounced in the background, where a madder lake (characterized by the
presence of alizarin and some purpurin) and a redwood lake are present in a pigment mixture that
includes both lead and zinc white.1 Tape covering the edges of the background provides evidence
that this change has occurred since 1929 (when the painting was lined by conservator J C Traas,
whose practice it was to tape the edges of the works before varnishing). The colour change, from
deep purplish grey to dull greenish grey, is due to loss of the organic red component of the
mixture. Similarly, the loss of depth and modelling evident in the dark clothing of the figure may
be attributed to discolouration of the lake components in the red glaze layer. By contrast, pigment
containing redwood and purpurin (probably Kopp’s purpurin) present in Bottle with Peonies and
Blue Delphiniums and Glass with Yellow Roses has darkened to a brownish hue. The darkening
of the lake in Bottle with Peonies is most pronounced, in particular where it is used mixed with
other pigments in the foreground and flowers, and applied on its own to paint the petals. The
discolouration has caused loss in intensity of van Gogh’s intended complementary red-green
colour scheme. Field (1841) described how ‘The fugitive colours do less injury in the
shadows…of a picture, because they are applied purer and in greater body’. A typical example
occurs in the background of Glass with Yellow Roses, where the crimson glaze applied thickly
over the dark underpaint appears well preserved. Conversely, where the same lake has been
painted more thinly, over the pale green leaf and in the glass, it has discoloured significantly, as
observed in the paint reconstructions. In Flame Nettle in a Flowerpot, purpurin alone was
identified in the lake pigment. The paint, which exhibits a characteristic orange fluorescence in
UV illumination, appears well preserved where relatively thickly applied over a dark underlayer.
A cochineal lake containing tin and starch was used for the thickly applied contour lines in
Agostina Segatori, from van Gogh’s last year in Paris. Where the pure lake has been thinly
applied over white in the kimono of the background figure, it has faded almost completely;
elsewhere it appears relatively well preserved. A tin-containing cochineal lake has also been used
with other pigments in the jacket, and probably the hat, in Portrait of Lucien-Etienne Martin.1
Both are now a flat, drab blue grey, lacking modelling. In contrast, paint that has been protected
from light by the frame gives an impression of how the drapery may have looked originally: a
deep, warm violet (Figure 5). The dramatic loss of colour of cochineal pigments in this work
confirms other similar findings in van Gogh’s paintings (Cadorin 1991). The most severe colour
loss occurs in those paintings containing lakes on tincontaining substrates. This corresponds to
the paint reconstructions; Saunders and Kirby (1994) have reported similar findings. These lakes
are the most vivid: loss of their intense colour has had a significant visual impact. The most
extreme fading has occurred in the two paintings where red lakes have been used in mixtures
containing lead and zinc whites. The full implication of the colour change in Portrait of LucienEtienne Martin is well illustrated by comparison with the cochineal/Sn reconstruction mixed with
white pigment. By the end of the ageing period the tone of the paint had changed from a bright
lilac to a dull grey, closely similar to the effect evident in the painting (Figure 6).
Surface deterioration
Characteristic surface phenomena were observed in both the reconstruction samples and the
paintings. The most significant, ‘spotting’, was associated with purpurin-containing lakes: for
example, a glaze in the background of Glass with Yellow Roses (Figure 7). Under a low powered
binocular microscope (40×) the spots appear as localized aggregations, radiating from larger,
intensely coloured areas. Comparable effects were visible on the surface of a similar lake in
Flame Nettle in a Flower Pot. This phenomenon was not observed in the cochineal-containing
paints, or in any of the madder reconstruction samples. A second phenomenon, raised, jelly-like
lumps, was observed in all the samples and mixtures containing brazilwood. These lumps were
present in the samples after one week of artificial ageing and in the samples protected from light,
suggesting they may be an inherent characteristic of brazilwood lake paints. The number of
lumps was greater in brazilwood reconstruction samples containing a lead drier. These samples
deteriorated more rapidly, perhaps because of accelerated drying of the paint. Evidence of jellylike lumps was also found in Head of an Old Woman, in the redwood and madder lake in the
background (Figure 8),1 and in the lake glaze on her lips. In all the paintings, cochineal and
purpurin/redwood-containing lakes showed a tendency to form deep, localized, mechanical
cracks, particularly in small areaswhere the lake had been applied pure and thickly. So severe is
the deterioration in Agostina Segatori that colour saturation has been lost, owing to light
scattering at the crumbly surface (Figure 9). The same effects, and the first signs of deterioration,
were seen in most of the cochineal reconstruction samples and were most pronounced in those on
a tin-containing substrate with starch. Similar deterioration of starch-containing lake paints has
been observed in works by Renoir and Monet.5 Of the pigments prepared as reconstructions, the
cochineal lakes were least similar to their equivalents in the paintings: in general, they altered
very little. In 19th century French and English colour literature, much is made of the extreme
fugacity of cochineal lakes, yet only the cochineal/Sn reconstruction samples faded significantly.
Fading occurred least in the very dark pigment samples and most where the lake was mixed with
white, chalk and starch. Of all the sample pigments, the cochineals contained the coarsest
particles and produced relatively
Figure 5. Detail from Portrait of Lucien- Etienne Martin showing fading of cochineal lake (tincontaining substrate): red lake present in mixture in light-protected area of the background
(right) and fading in exposed area (left)
Figure 6. Fading of cochineal reconstructions mixed with lead white; from right to left: C1, C2,
C3 and C4
Figure 7. ‘Spotting’ in passage of Kopp’s purpurin lake, used as a glaze in the background of
Glass with Yellow Roses
thick paints. The thicker, relatively opaque and deep purplish paints faded more slowly than the
more transparent films produced from the other lakes. The permanence of Kopp’s purpurin and
madder lakes, and the marked impermanence of eosin and brazilwood lakes, are consistent with
statements from 19th century sources. Documentary references to the instability of the tin-based
lakes and the influence of adulteration, at both pigment-making and grinding stages, on
permanence were borne out by the study.
Conclusion
Van Gogh’s awareness of the fugacity of some red lake paints and his attempts to compensate for
this are demonstrated in the paintings examined. Though correctly surmising that a solid
application of paint would reduce the effects of colour change, he could not have anticipated the
impact of changes in colour especially where lake is mixed with other pigments.6 Nor would he
have predicted the profound effects of surface deterioration that are most pronounced in areas of
thickly applied pure red lake. Perhaps the original brilliant scarlet of tin-cochineal found in van
Gogh’s paintings from January 1887, and its luscious consistency when associated with starch,
tempted the painter, despite its impermanence. Equally, financial restrictions likely necessitated
the purchase of lower quality pigment, which resulted in pronounced changes in the appearance
of these paintings. In the reconstructions, the most fugitive lakes faded in less than 500 h of
lightageing, equivalent to under 10 years’ exposure to museum lighting conditions. It is possible
that redwood- and eosin-containing paints may have faded within or soon after Van Gogh’s short
lifetime. In uncontrolled lighting conditions, fadingand colour shifts are likely to have occurred
more rapidly. The results of this study should be taken into account in any interpretation of van
Gogh’s application of 19th century colour theory, his assimilation of artistic influences, and his
use of colour as an inherently emotive vehicle. The relatively many variables considered in this
study provided a range of criteria for evaluating the fading and surface deterioration of red lakes
similar to those identified in van Gogh’s paintings. The findings may have wider relevance for
the study of his contemporaries. Future studies of the naturally and artificially aged paints will
examine their degradation products and the effects of oxygen exclusion on fading. Studies of the
depth of fading in the samples, using paint cross-sections, and the photochemistry of fading are
planned.
Acknowledgements
Leo Jansen, Department of Research, Van Gogh Museum. Shell Research and Technology
Centre, Amsterdam. René Hoppenbrouwers, SRAL, Wim van der Zwan, Old Holland Classic Oil
Paints. Muriel Geldof and Maarten van Bommel, David Saunders, Arie Wallert, Luuk van der
Loeff and Clare Richardson, TSR London.
Notes
1 See Van Bommel, M, Geldof, M and Hendriks, E, 2005, ‘Examination of the use of organic red
pigments in paintings by Vincent van Gogh (November 1885 to February 1888)’, ArtMatters 3,
submitted.
2 Letter 552/441, ca. 21 December 1885.
3 See, for example, letters 550/439, 14 December 1885, and 580/464 24 February 1888.
4 Letter 598/476; ca. 11 April 1888.
5 Unpublished technical research by Aviva Burnstock.
6 Letter 541/430, early November 1885.
Figure 8. Jelly-like lumps on the surface of redwood- and madder-containing lake paints from
Portrait of an Old Woman
Figure 9. Detail of brushstroke of starchcontaining cochineal lake (tin-containing) from Agostina
Segatori in the Café du Tambourin
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