National Gallery Technical Bulletin Volume 14, 1993

Analyses of Paint Media

Raymond White and Jennifer Pilc

Artist	Picture	Date	Sample	Medium	P/S	Oil type	Notes	
Attributed to the Master of Saint Francis	‘Crucifix’ NG 6361	c.1285	1. Flesh paint of Christ
2. Green from gilding	Egg
Copper resinate/oil			1	
Jacopo
di Cione and
Workshop	‘Coronation of the Virgin, with Adoring Saints’ NG 569

	1370–1 	1. Brown glaze-like paint
2. Green paint beneath brown layer
3. Greenish-brown paint
4. Black jewel in crown
5. White garment, upper left-hand saint
6. Blue of robe, above red book
7. Red, bole-like ground

	Egg
+ a little oil
Egg
Egg Egg Egg
Egg
+ a little oil
Glue
			2	
	‘Pentecost’ NG 578	1370–1	1. Darkened, insoluble
varnish trapped under fitment	Oil + resin				
Niccolò di Buonaccorso	‘The Marriage of the Virgin’ NG 1109	1372–88	1. Pale blue (reverse)
2. Red lake paint (reverse)	Egg Egg				
Piero della Francesca	‘The Nativity’ NG 908	1470s	1. Blue sky
2. Discoloured green of distant trees	Oil
Oil	2.8 3.0	Walnut Walnut		
Cosimo Tura	‘Saint Jerome’ NG 773	c.1475 	1. Darkened green or black of tree trunk
2. Red of hat
3. Pale green grass
4. Blue sky
	Oil
Oil
Egg
+ some oil
Egg
+ some oil	2.4
2.2
	Walnut Walnut
	3	
	‘The Virgin: Fragment of an Annunciation’ NG 905	1490–5	1. Green grass in background
2. Blue of Virgin's robe
3. Green underpaint from canopy over throne	Oil
Oil
Egg	2.3
2.8	Walnut Walnut		
Antonio and Piero del Pollaiuolo	‘The Martyrdom of Saint Sebastian’ NG 292	1475	1. White of sleeve
2. Green of foliage
3. Brown foliage in foreground	Oil
Oil
Oil
+
asphaltum	3.0
2.5
2.3	Walnut Walnut Walnut		
Antonello da Messina	‘Saint Jerome in his Study’ NG 1418	early 1460s
	1. Brownish paint, top right-hand corner
	Oil
	2.4
	Walnut 		
	‘Christ Blessing’ NG 673	1465	1. Black background	Oil	2.6	Walnut		
Carlo Crivelli	‘The Annunciation, with Saint Emidius’ NG 739	1486	1. White of window frame
2. Green of Virgin's robe
3. Brown of planks below shelf
4. Thick globular mordant of gilding from capital of left-hand pilaster	Egg
+ some oil
Oil mainly
+ some resin Egg tempera
Egg mainly + a little oil	2.2	Walnut	4	
Gerolamo Romanino	‘The Nativity with Saints Alessandro of Brescia, Jerome, Gaudioso and Filippo Benizzi’ NG 297	c.1525	1. Purplish wing, upper right-hand edge, within lunette
2. Reddish-purple drape, right-hand edge	Egg
Oil + egg				
Paolo Veronese	‘Allegory of Love I ('Unfaithfulness')’ NG 1318	mid-1570s	1. Brownish-green leaves, left-hand edge
2. White highlight of drape
3. Red highlight glaze of
red drape, right-hand edge	Oil +
some resin
Oil
Oil	1.7
1.8
1.7	Linseed
Linseed Linseed	5	
Annibale Carracci	‘Silenus gathering Grapes’
NG 93
	1597–1600 
	1. Greyish-white of water
2. Dark brown earth
	Oil + some egg tempera Oil	2.4
1.6
	Walnut Linseed

	6	
	‘Christ appearing to Saint Peter on the Appian Way (Domine Quo Vadis?)’ NG 9	1601–2	1. Brownish shadow of robe
2. Blue of sky, top right-hand edge
3. Green of trees	Oil + ? Oil
Oil
	2.6
2.4
2.0
	Walnut Walnut
Linseed/ walnut?		
	‘The Dead Christ Mourned’ NG 2923	c.1604	1. White highlight of shroud
2. Yellow silk brocade	Oil 
Oil	3.3
1.4	Walnut Linseed		
Caravaggio	‘Boy bitten by a Lizard’
NG 6504	15981600	1. White highlight of drape, left-hand edge	Oil + some egg tempera	3.1	Walnut	7	
Guido Reni	‘Christ embracing Saint John the Baptist’ NG 191	late 1630s	1. White garment of Saint John
2. Flesh paint of Saint John's hand	Oil Oil	1.8
1.3	Linseed Linseed		
Domenichino	‘Saint George killing the Dragon’ NG 75
	1610–11 	1. Blue sky
2. Dark brown tree trunk
	Oil
Oil
	2.8
2.4
	Walnut Walnut
		
	‘Landscape with Tobias laying hold of the Fish’ NG 48	1617–18	1. Blackish brown of trees	Oil	1.5	Linseed		
Guercino	‘The Incredulity of Saint Thomas’ NG 3216	1621	1. Light blue of Christ's garment
2. Yellow paint of Saint Thomas's robe
3. Red glaze-paint from folds of Saint Thomas's robe	Oil +
some egg
Oil
Oil +
some resin	2.7
2.7
2.4	Walnut Walnut Walnut	8	
Luca Giordano	‘Saint Anthony of Padua miraculoulsy restores the Foot of a Self-mutilated Man’ NG 1844
	c.1700
	1. Red paint of architecture
2. Yellow highlight of architecture
	Oil
Oil
	1.7
1.5
	Linseed Linseed
		
	‘The Martyrdom of Saint Januarius’ NG 6327	c.1690–1702	1. Warm white of rock
2. Dark reddish brown of architecture	Oil
Oil	1.6
1.7	Linseed Linseed		
Canaletto	‘Venice: Campo S. Vidal and Santa Maria della Carità ('The Stonemason's Yard')’ NG 127	c.1730	1. Grey underpaint
2. White of textile
3. Yellowish cloud
4. Blue sky
5. Brownish-red wall	Oil
Oil
Oil
Oil
Oil	1.8
1.8
1.8
1.3
1.3	Linseed Linseed Linseed Linseed Linseed		
Master of the
Mornauer
Portrait	‘Portrait of Alexander Mornauer’
NG 6532	1470s	1. Dark cloak of sitter
2. Blue repaint of background	Oil
Oil	1.7
4.0	Linseed Poppy	9	
South German School	‘Saint John on Patmos’ NG 4901	c.1460/70s	1. Brownish green, right-hand edge
2. White of clouds
3. Ground layer	Oil
Oil
Oil	1.3
1.4
1.4	Linseed
Linseed Linseed	10	
Style of Martin Schongauer	‘The Virgin and Child in a Garden’ NG 723	1469–91	1. Green leaf of tree	Oil
+ a little resin	2.6	Walnut	11	
Lucas Cranach
the Elder	‘Cupid complaining to Venus’ NG 6344	probably 1530s	1. Mid-blue paint, left-hand edge
2. Browned green paint of leaves, left-hand edge
3. Cream coloured clouds	Oil
Oil
Oil	1.9
1.8
1.7	Linseed
Linseed Linseed		
Lucas Cranach
the Elder	‘Charity’ NG 2925	after 1537	1. White of sky, right-hand edge
2. Blue of sky, right-hand edge
3. Green foliage, left-hand edge	Oil
Oil
Oil	1.8
1.6
1.8	Linseed
Linseed Linseed		
Jakob Seisenegger	‘Portrait of a Girl’ NG 4206	c.1545–50	1. Green background
2. Black of dress, bottom edge	Oil
Oil	1.3
1.8	Linseed Linseed	12	
Johann Liss	‘Judith in the Tent of Holofernes’ NG 4597	1622–3	1. Black of helmet
2. White sheet, behind body	Oil
+ resin Oil	1.4
3.6	Linseed Walnut	13	
Johann Carl Loth	‘Mercury piping to Argus’
NG 3571	late 1650s	1. Red garment of Mercury
2. Cream-coloured background	Oil
Oil	1.7
1.7	Linseed Linseed		
Govert Flinck	‘Self Portrait aged 24’ NG 4068	1639	1. Olive-grey background
2. Black of coat	Oil
Oil	1.6
1.9	Linseed Linseed	14	
Follower of Rembrandt	‘An Old Man in an Armchair’
NG 6274	1652	1. Brownish-red lower ground
2. White impasto of cuff
3. Brownish-black paint	Oil
Oil
Oil + resin	1.8
2.6
1.4	Linseed Walnut Linseed	15	
G. van den Eeckhout	‘Rebekah and Eliezer at the Well’ NG 6535	1661	1. Blue paint of sky
2. Grey-white of stone
3. Dark brown shadow	Oil
Oil
Oil + resin	1.9
1.7
1.9	Linseed Linseed Linseed	16	
Edouard Manet	‘Music in the Tuileries Gardens’ NG 3260
	1862 	1. Ground
2. Pale blue of sky
3. Black of shoe of left-hand man
4. Green of trees, right-hand edge
5. White of dress of girl kneeling, centre
6. Brown earth, bottom edge
	Oil
Oil
Oil
Oil
Oil
Oil
	1.9
2.9
2.7
1.8
4.4
3.1
	Linseed Poppy + linseed Poppy + linseed Linseed
Poppy
Poppy +
some
linseed
	17 	
	‘The Execution of Maximilian (fragment)’ NG 3294A	1867–8	1. Blue sky	Oil	4.1	Poppy	18	
Claude Monet	‘Bathers at La Grenouillère’ NG 6456	1869	1. Ground, left-hand edge
2. Green foliage, right-hand side
3. Green foliage, upper left-hand side
4. White impasto, highlight of wave	Oil
Oil
Oil
Oil	1.4
4.3
4.0
4.1	Linseed Poppy
Poppy
Poppy	19	
Claude Monet	‘The Beach at Trouville’ NG 3951	1870
	1. Ground
2. White impasto by knee of woman in blue
3. Black dress, right-hand figure
4. Grey-blue sky	Oil
Oil
Oil
Oil
	1.4
4.2
1.8
3.0
	Linseed Poppy
Linseed Poppy + linseed
		
	‘The Petit Bras of the Seine at Argenteuil’ NG 6395
	1872
	1. Lower ground
2. Upper lilac ground
3. Dark green river bank
4. White impasto highlight of river	Oil
Oil
Oil
Oil
	1.4
1.6
3.4
3.9
	Linseed Linseed Poppy?
Poppy
		
	‘The Gare St-Lazare’ NG 6479
	1877	1. Ground
2. Dark paint of roof of station
3. Greyish-white of steam	Oil
Oil
Oil
	1.5
2.6
3.9
	Linseed Linseed + poppy Poppy
		
	‘Lavacourt under Snow’
NG 3262	1881	1. Ground, bottom edge
2. White of snow, bottom edge
3. Dark blue of shadow on snow
4. Dark green	Oil
Oil
Oil
+ resin Oil	2.1
4.5
2.7
2.5	Walnut?
Poppy
Walnut
Walnut		
Camille Pissarro	‘Fox Hill, Upper Norwood’ NG 6351
	1870 1871
1877	1. Ground
2. White sky
3. Blue sky
4. Dark green, bottom edge	Oil
Oil
Oil
Oil
	2.9
4.4
2.7
3.0

	Walnut Poppy Walnut Walnut	20	
	‘The Avenue, Sydenham’ NG 6493
		1. White cloud
2. Pale blue of sky
3. Dark green of grass
4. Greyish-brown paint, left-hand edge	Oil
Oil
Oil
Oil
	4.1
4.6
2.4
2.5

	Poppy Poppy Walnut Walnut
		
	‘The Cote des Boeufs at l'Hermitage’ NG 4197		1. Ground
2. White impasto of house, centre
3. Dark blue impasto, top of tree trunk
4. Red paint, bottom edge	Oil
Oil or oil + fats?
Oil
Oil +
Beeswax	1.6
2.8
3.0	Linseed Walnut or poppy + fats? Walnut
Walnut		
Alfred Sisley	‘The Watering Place at Marly-le-Roi’ NG 4138	1875	1. Brownish ground
2. White snow, bottom edge
3. Black paint, right-hand edge
4. Light bluish grey of stream	Oil
Oil
Oil
Oil	1.8
4.7
1.4
3.3	Linseed
Poppy
Linseed
Poppy +
some
linseed		
Pierre-Auguste Renoir	‘At the Theatre (La Première Sortie')’
NG 3859
	1876–7
	1. Ground
2. White collar of right-hand figure
3. Dark blue dress, right-hand figure
	Oil + resin
Oil + resin
Oil + resin
	1.4
1.8
1.5
	Linseed Linseed
Linseed
	21	
	‘Boating on the Seine’ NG 6478
	c.1879	1. Ground
2. White highlight on wave crest
3. Dark blue from foreground	Oil
Oil
Oil mixture
	3.9
4.2
1.9
	Poppy Poppy Linseed + a little castor
		
	‘The Umbrellas (Les Parapluies')’ NG 3268	1881–6	1. Ground, right-hand turnover
2. White impasto, right-hand girl's hat
3. Red of hair, right-hand edge
4. White of arm, left-hand turnover
5. White cloud, top edge
6. Dark blue, right-hand woman's dress	Oil
Oil
Oil
Oil
Oil
Gouache (gum)	1.9
5.3
5.2
1.7
1.8	Linseed Poppy
Poppy Linseed
Linseed		
Berthe Morisot	‘Summer's Day’ NG 3264	1879	1. Ground
2. White highlight impasto from dress of centre figure
3. Grey paint of dress of centre figure
4. Dark blue dress, left-hand figure	Oil
Oil
+ resin Oil
+ resin Oil	1.2
4.3
2.8
4.0	Linseed Poppy
Poppy +
linseed
Poppy	22	
Paul Cezanne	‘Hillside in Provence’ NG 4136	c.1886	1. Ground
2. White impasto highlight of rocks
3. Greyish blue of distant hills
4. Yellow, lower right-hand edge	Oil
Oil
Oil
Oil	1.3
2.6
2.7
2.5	Linseed Walnut
Walnut Walnut	23	

Notes to the Table

1. Samples 1 and 2 were examined by FTIR-IR microscopy.
2. A study of these two Trecento panels has been reported (note 1–2).
In NG 569 the fragment of paint from one of the black jewels in the crown, sample 4, appeared to be in egg tempera, as was the case with samples 2, 3 and 5. Here, however, the paint was very rich in non-drying lipids, which might suggest the use of egg yolk mainly. The transparency of the essentially egg tempera medium in sample 1 (brown glaze) and the degree of colour saturation of the ultramarine pigmented sample 6 (blue robe) appears to have been augmented by the addition of a little drying oil.
3. In the case of Tura's ‘Virgin’ (NG 905) samples of green paint from the grass in the background and blue paint from the Virgin's robe were identified as being bound in walnut oil, whereas a green under-paint from the canopy over the throne was found to be bound principally by egg tempera; nevertheless, there was a small amount of drying oil, possibly from vestiges of a green upper layer. This matched quite well the pattern observed in other paintings by Tura in the Collection (NG 3070 and NG 772). 3 His ‘Saint Jerome’ (NG 773) had a much leaner and more matt appearance overall. Whereas a very dark green or black tree trunk contained walnut oil (with no evidence of resin) and the red paint of a hat was bound very leanly with walnut oil, both the pale green paint of the grass and the blue sky paints were found to contain predominantly egg tempera medium with a small amount of drying oil.
4. The examination of the medium presented here represents further investigation carried out on works by Carlo Crivelli. In the past (note 3–4), Crivelli paintings have shown quite a sophisticated use of both egg tempera and oil media, and the current work – NG 739 – proved to be no exception.
Brown, rather 'dry' paint was identified as in egg tempera medium alone. White paint of a somewhat richer quality seemed to be composed of egg tempera with a little drying oil. Neither of these paints was found to contain any detectable amounts of diter-penoid or triterpenoid resins. However, green paint (from the Virgin's robe) consisted of oil medium predominantly, but with some egg tempera. In this case, unlike the other samples, there was also clear evidence for the inclusion of pine resin from the presence of methyl dehydroabietate and methyl 7–oxode-hydroabietate (by GC-MS).
Adhesive from the gilding, sampled from the capital of an enjoined pilaster and which appeared as rather globular droplets under the optical microscope, was shown to contain mainly egg – with a dash of oil – but no resin.
5. Some ten years ago samples were taken from Veronese's ‘Allegory of Love I’, NG 1318 (note 5). Since that time other ‘Allegories’ in the series have been examined, as well as NG 931, ‘Saint Mary Magdalene laying aside her Jewels’ (note 6). In several works by Veronese, we have found examples of his preference for the use of walnut oil in the whites and pale colours, with evidence of copper resinate in transparent greens. In some works, however, these preferences have not been encountered. NG 1318 was just such a case and we were anxious to re-examine fresh samples of green and white as a check on our original findings. A sample of white highlight from a white sheet proved to be linseed oil following GC analysis and, reassuringly, the methyl palmitate/methyl stearate ratio was found to be close (1.8) to our original measurements of 1.9. The presence of oil was also supported by FTIR analysis employing the IR-microscope.
A sample of green paint from a leaf in the original investigation, aside from containing linseed oil, was not demonstrated to be a copper resinate-based paint. In part this may have been due to the fact that the analysis had been carried out by GC alone and we became acutely aware, following the acquisition of GC-MS, that additions of natural resin could easily be missed without the added selectivity and sensitivity of the mass-spectrometer. Upon further investigation (using the FTIR-IR microscope) it was possible to detect resinate bands. GC of the sample, following an infra-red investigation, produced a chromatogram, which pointed to the use of linseed oil and which, moreover, possessed a slight undulation of the base-line in the diterpenoid region normally associated with methyl dehydroabietate. A sample of red glaze-like paint from a drape – not examined in the original study – was found to contain linseed oil.
6. Annibale Carracci's ‘Silenus gathering Grapes’ (NG 93) consists of two irregularly shaped wooden panels and is thought to have been part of the decoration originally of a harpsichord or similar musical instrument. A sample of the brown foreground from the bottom edge of the larger panel was identified as linseed oil by GC. However, a curiously fresco-like greyish-white paint was found to be a mixture of egg tempera and – predominantly – oil (again by GC). The substantial palmitate-to-stearate ratio was well within the region associated with walnut oil and, even allowing for distortion by the non-drying tempera fats, could not conceivably represent linseed oil. FTIR-microscopy on a section substantially confirmed these conclusions, but different areas of the section seemed to vary markedly as to the intensity of protein and drying lipid bands. Thus the curious appearance of this particular area of paint may be the result of a failed emulsion.
NG 2923, ‘The Dead Christ Mourned’, by the same artist appeared to contain a white, slightly impasto-like paint, which was based on heat-bodied walnut oil as medium. Paint of the yellow silk brocade, in contrast, was identified as linseed oil, which had not been heat-bodied.
Walnut oil was identified as binder in samples 1 and 2 from ‘Christ appearing to Saint Peter on the Appian Way (Domine Quo Vadis?)’ (NG 9). Sample 3, which was a fragment of green paint from the trees, exhibited an ambiguous palmitate/stearate ratio of 2.0 at the boundary of linseed and walnut oils. Moreover, by GC, there was some evidence for poorly resolved components in the general diterpenoid region of paint from a brownish, heavily cracquelured paint on the robe (sample 1). A portion of this sample has been reserved for future examination by GC-MS.
7. One sample was taken from Caravaggio's ‘Boy bitten by a Lizard’ (NG 6504), a cool highlight of a white drape. FTIR-microscopy clearly indicated a proteinaceous component among the drying glyc-erides of the binder in the same layer. Thus one must conclude the presence of some form of egg/oil emul-sion. GC revealed a significant amount of dimethyl azelate component, relative to methyl palmitate, but with an obvious dilution of the drying oil by non-drying fats. The palmitate/stearate ratio was in the upper range of that expected for walnut oil. Thus the drying oil component is likely to be walnut rather than linseed oil.
8. Sample 3, a red glaze-paint, was found to contain some pine resin by GC.
9. A fragment of a non-original blue background was examined by GC only. The sample taken was a light scraping to avoid material from a lower varnish and paint layer below. The results suggested that a heat-bodied poppyseed oil had been used as medium. The overall chromatogram indicated some measure of maturity and probably represents an eighteenth-century overpaint. Original paint from the dark cloak of the sitter was identified as bound in linseed oil (note 7).
10. Sample 1 was considered a possible candidate for a copper resinate green paint which had browned. Neither GC nor FTIR microscopy was able to demonstrate any presence of resin within. However, GC revealed the use of a heat-bodied drying oil (note 8). In this case the P/S ratio confirmed linseed oil. Hence the darkening would seem to result from the darkening of the oil medium alone. Similarly a warm white paint of a distant cloud and a sample of earth were identified as being bound in linseed oil medium; on this occasion it was not heat pre-polymerised.
11. GC confirmed the presence of walnut oil, much as had been identified in a sample of blue paint at the previous investigation some years ago (note 9). The chro-matogram hinted at the presence of dehydroabietic ester, but was not sufficiently clear for the unambiguous identification of pine resin. FTIR using the IR microscope in transmittance mode (on a thin section cut from a sample embedded in silver chloride) did suggest the presence of a resinate pigment.
12. Here the question had been posed as to whether there might be copper resinate in the green background. GC of the principal paint layer only indicated the use of linseed oil paint medium. A sample of black paint from the dress also contained linseed oil, but this time it had been heat pre-polymerised. FTIR results for these two samples were rather disappointing, but once again there was no evidence for resin in the medium.
13. A rich black paint of the helmet provided a gas-chromatogram which suggested the use of linseed oil and some diterpenoid resin. In particular, one component had the same retention time as larixyl acetate (note 10–12) and so it would seem that larch resin (Venetian turpentine) is indicated. This was further supported by FTIR-IR microscopy.
14. Linseed oil was identified in both samples and neither medium appeared to have been subjected to heat-bodying or to contain resin. The amount of dimethyl azelate component in the sample of black paint (sample 2) was slightly less than that of methyl palmitate, though not seriously so. Although this was more likely to be the result of the ageing pattern associated with the black pigments rather than an input of egg tempera medium, it was decided to check this by FTIR microscopy. No evidence for proteinaceous content was found.
15. Samples 2 and 3 showed evidence for heat pre-polymerisation, with the brownish-black paint containing traces of pine resin too.
16. Sample 3, a dark brown shadow, showed signs of 7–oxodehydroabietic ester in its chromatogram, suggesting an addition of pine resin in this instance.
17. The interpretation of the P/S ratios for samples 2, 3 and 6 follows the guidelines as set out in Note 23 below.
18. During the course of cleaning and reassembling the sections of this work (note 13) a sample of blue sky was identified as being bound in a very lean poppyseed oil medium. This would help to explain the vulnerability of this layer. Remnants of a greyish, unpig-mented surface coating between the paint and varnish were identified as a somewhat immature walnut oil. This represented most probably the remnants of an oiling-out layer.
Samples of white and dark green paints from fragment NG 3294C, examined and reported upon earlier (note 14), had P/S ratios of 3.0 and 3.5 suggestive of the use either of walnut oil or, and more likely, a mixture of poppyseed and linseed oils. Similar P/S ratios (3.0, 3–9 and 3.4) were reported from two other paintings by Manet (‘Déjeuner sur l'herbe and Le Balcon’) both in the Louvre (note 15).
19. NG 6395 provided two paint samples which exhibited low azelate/suberate ratios and so provide evidence of heat pre-polymerisation. These were samples 2 (upper ground) and 4 (white impasto highlight). Sample 3 (dark green) gave an ambivalent P/S ratio bordering on the overlap areas of poppyseed and walnut oils, but is most likely to represent the former. Sample 3 of NG 3262 contained a little pine resin mixed with the walnut oil.
20. A white impasto from ‘The Cote des Boeufs at l'Hermitage’ (NG 4197) at first sight seemed to contain some non-drying egg fats. However, there was no evidence for protein associated with egg tempera and so it must be concluded that either a non-drying oil or fat (but not castor oil in this case – see Note 21) had been added to the main drying oil component. This of course would affect the P/S ratio somewhat and makes the identity of the drying oil difficult to ascertain. Since the ratio was towards the upper limit of the walnut region, we may postulate the use of walnut or possibly poppyseed oil. Sample 4 contained vermilion, a very heavy pigment which tends to settle within the medium when such paint is stored in tubes and when painted out is inclined to settle and leave an oil-rich surface to the paint layer. In this sample, the medium was found to contain a little beeswax in addition to the oil. This would thicken the medium and reduce the tendency for the vermilion to settle before the oil has gelled sufficiently to fix the particles in place.
21. In NG 3859, the ground and dark blue paints showed evidence of heat prepolymerisation of the linseed oil, whereas the white paint did not. All showed evidence of the inclusion of pine resin.
A white highlight from ‘Boating on the Seine’ (NG 6478) contained heat-bodied poppyseed oil. Sample 3 – blue paint from the foreground – was identified as linseed oil mixed with a little non-drying oil. This would suggest a commercially prepared paint, the purpose of the non-drying oil (identified as castor oil by the presence of methyl ricinoleate) being to retard the drying of the oil, prevent the paint from hardening in the tube and, perhaps, to provide a plasticiser.
22. Here both samples 2 and 3 contained some diter-penoid resin components but not pine resin, rather some form of hard copal.
23. Media analyses were carried out on a range of paintings by Impressionists and an outline only of the results was published (note 16). In all, 61 samples have been examined, of which (approximately) 31% were based on poppy oil, 34% on linseed oil, 23% on walnut oil and, possibly, 11% on a mixture of poppy and linseed oils. About 10% of this group contained additives in the form of pine resin diterpenoids and 8% had a stand or 'fat' oil component, that is to say, an oil which has been heat prepolymerised or heat-bodied.
Some comments on interpretation of 'walnut region' palmitic-to-stearic ester ratios (c. 2. -2–3. -3) should be made at this point in relation to the results below. Several paintings contain poppyseed oil and linseed oil in the same work, these being used with different colours. In such cases, where areas of paint give fatty ester ratios intermediate between the two extremes, the results have been cautiously interpreted as 'poppy + linseed oil mixture'. It is, however, a reasonable first assumption that those pictures with samples which indicate consistently the presence of walnut oil, or walnut oil with only one of the other oils, are less likely to contain mixtures of linseed and poppyseed. So here the results obtained have been attributed to the presence of walnut oil rather than mixtures of linseed and poppyseed oils. Such is the case with NG 4136.

References

1. D. Bomford, J. Dunkerton, D. Gordon and A. Roy, ‘Art in the Making: Italian Painting before 1400’, London 1989, pp. 156–89, 197–200.
2. J. Dunkerton, J. Kirby and R. White, 'Varnish and Early Italian Tempera Paintings', ‘Cleaning, Retouching and Coatings: Technology and Practice for Easel Paintings and Polychrome Sculpture’ (ed. J. S. Mills and P. Smith), London 1990, pp. 63–9, 149–50.
3. J. S. Mills and R. White, 'Analyses of Paint Media', ‘National Gallery Technical Bulletin’, 11, 1987, pp. 92–5.
4. J. S. Mills and R. White, 'The Gas Chromatographic Examination of Paint Media. Some Examples of Medium Identification in Paintings by Fatty Acid Analysis', ‘Conservation and Restoration of Pictorial Art’ (ed. N. Brommelle and P. Smith), London 1976, pp. 72–7.
5. J. S. Mills and R. White, Analyses of Paint Media', ‘National Gallery Technical Bulletin’, 7, 1983, pp. 65–7.
6. J. S. Mills and R. White, Analyses of Paint Media', ‘National Gallery Technical Bulletin’, 12, 1988, pp. 78–9.
7. S. Foister, 'The Portrait of Alexander Mornauer', ‘The Burlington Magazine’, CXXXIII, September 1991, pp. 613–8
8. J. S. Mills and R. White, Analyses of Paint Media', ‘National Gallery Technical Bulletin’, 13, 1989, pp. 69–71.
9. J. S. Mills and R. White, Analyses of Paint Media', ‘National Gallery Technical Bulletin’, 4, 1980, pp. 65–7.
10. J. S. Mills and R. White, 'Natural Resins of Art and Archaeology. Their Sources, Chemistry and Identification', ‘Studies in Conservation, 22’, 1977, pp. 12–31.
11. J. S. Mills and R. White, 'Organic Mass-Spectrometry of Art Materials: Work in Progress', ‘National Gallery Technical Bulletin’, 6, 1982, pp. 3–18.
12. J. S. Mills and R. White, ‘The Organic Chemistry of Museum Objects’, London 1987, pp. 87–90.
13. J. Wilson-Bareau, ‘Manet: The Execution of Maximilian: Painting, Politics and Censorship’, London 1992.
14. J. S. Mills and R. White, Analyses of Paint Media', ‘National Gallery Technical Bulletin’, 3, 1979, pp. 66–7.
15. S. Delbourgo and J-P. Rioux, 'Manière et matière des impressionnistes. Contribution a l'étude de la matièe picturale', ‘Annales du Laboratoire de Recherche des Musées de France’, 1974, pp. 34–42.
16. D. Bomford, J. Kirby, J. Leighton and A. Roy, 'Impressionist Paint Media', ‘Art in the Making: Impressionism’, New Haven and London 1990, pp. 72–5.

Series Editor: Ashok Roy

© National Gallery Publications Limited 1993
All rights reserved. No part of this publication may be transmitted in any form or by any means, electronic, or mechanical, including photocopy, recording, or any information storage and retrieval system, without the prior permission in writing from the publisher.

First published in Great Britain in 1993 by National Gallery Publications Limited 5/6 Pall Mall East, London SW1Y 5BA.

British Library Cataloguing-in-Publication Data A catalogue record for this journal is available from the British Library.

ISBN 1 85709 033 0
ISSN 0140 7430

Edited by Diana Davies and Emma Shackleton

The publication of this volume of the ‘National Gallery Technical Bulletin’ has been made possible by the generous support of Mr and Mrs Frank Richardson of New York