For centuries gel mediums have been touted as the ‘secret medium’ of Renaissance artists such as Jan van Eyck. Among the proponents of this idea was the Secretary to the Royal Academy of Fine Arts in Paris, Jean-François-Léonor Mérimée. This article reviews the belief still held by many artists even today.
Italian Varnish was first mentioned by Jean-François-Léonor Mérimée in his 1830 book, De la Peinture à l’huile, as a “l’huile emplastique, que l’on prépare en Italie, de temps immémorial, et qui a la double propriété d’être très siccative et d’arrêter la tendance à couler des glacis les plus liquides.” (translated: “elastic oil, which has been prepared in Italy since time immemorial, and which has the double property of being fast drying and of preventing the tendency of liquid glazes to run.”) The recipe for Italian Varnish provided by Mérimée consists of litharge (lead oxide) heated in linseed or walnut oil and beeswax. To this mixture, mastic varnish made from mastic resin and turpentine was added to form a jelly-like substance. [60–64]
Mérimée advocated the use of varnish not only in glazes but throughout an oil painting. The recipe for Italian Varnish was accompanied by other mediums, Flanders Varnish and English Varnish, containing similar ingredients but prepared differently.
These mediums are of interest to artists today because many claims have been made over the past several centuries that they were used by artists of the Renaissance and later periods. Mérimée made the same claim in his book when he described Italian Varnish as an “oil prepared in Italy from a very remote period.”
Translated into English in 1839 by W. B. Sarsfield Taylor, Mérimée’s The art of painting in oil had a wider audience and arguably a longer-lasting impact on the view of earlier artists’ techniques. Mérimée wrote that he sought to research the processes of painting employed from the time of Van Eyck to the present, both through the analysis of early treatises and careful examination of paintings by the Old Masters. This interest was spurred by the recognition that many paintings from the fifteenth century were better preserved than the majority created in his own time and by the subsequent desire to discover the ‘secret’ of the Old Masters. [ix–x] He was convinced that early oil paintings were composed of oil and resin, and it was through oleoresinous mediums that Old Master paintings were better preserved and possessed greater transparency and brilliance. 
In addition to a comprehensive review of early and modern literature on the subject, Mérimée turned to the experience of restorers who found that paint from the fifteenth century was harder and more durable. It also possessed more resistance to solvents than recent works and showed an enamel-like quality when rubbed with a file [14–15].
For clarification, the text describing Italian Varnish is reproduced below from Mérimée’s book and Sarsfield Taylor’s translation in English. Also provided is a transliteration of Mérimée’s text as a comparison.
Italian Varnish by Jean-François-Léonor Mérimée
VERNIS QU’ON PEUT EMPLOYR EN PEIGNANT.
Vernis des Italiens.
J’ai déjà fait connaitre l’huile emplastique, que l’on prépare en Italie, de temps immémorial, et qui a la double propriété d’être très siccative et d’arrêter la tendance à couler des glacis les plus liquides.
On la prépare en faisant digérer, sur un feu doux; une partie de litharge broyée au dernier degré de ténuité, avec deux parties d’huile de lin ou de noix (1). On a soin de remuer souvent le mélange avec une spatule, afin de faciliter la combinaison.
Après plus ou moins de temps, suivant la quantité de matières sur lesquelles on opère, l’huile est intimement combinée avec litharge, au point qu’en en laissant tomber quelques gouttes sur un corps froid, elle se fige aussitôt comme de la graisse fondue. Si cet effet n’a pas lieu, c’est une preuve que l’opération a été arrêtée trop tôt. Il faut alors remettre l’huile sur le feu, et y ajouter au plus un dixième de cire blanche très pure: on le fait d’ailleurs, dans tous les cas, pour donner plus de consistance à cette préparation. Lorsque la cire est tout à fait incorporée, on verse l’huile sur une pierre à broyer; puis, à l’aide de quelques coups de molette, on empêche que la partie fluide ne se sépare en refroidissant, et l’on rend ainsi le mélange parfaitement homogène
Pour employer cette huile emplastique, on la délaie dans du vernis au mastic, en broyant ce mélange sur la palette On en forme ainsi une espèce de pommade qui s’étend avec facilité sous le pinceau, et qui reste sur le tableau comme on l’applique, sans couler aucunement: elle est donc très convenable pour les glacis.
Le mélange du vernis est nécessaire, parce que, sans cette addition, elle mousserait sous la brosse comme une dissolution de savon, au point qu’on ne pourrait rien discerner tant que les bulles de la mousse n’auraient pas disparu.
Cette combinaison d’huile et de litharge est en effet un véritable savon qui, à l’exception de la solubilité dans l’eau, a tous les autres caractères des savons ordinaires formés par la réunion de d’huile et d’un alcali.
Il serait donc mieux de la préparer dans l’eau bouillante, comme on prépare les savons ordinaires; car il n’est pas aisé de régler le feu de manière que la température ne dépasse pas le degré convenable, tandis que celle de l’eau bouillante est toujours la même.
A mesure que l’eau se dissipe par l’évaporation, on en remet de nouvelle, et lorsque la combinaison le est achevée, l’eau qui reste au fond du vase est sans couleur et a acquis une saveur sucrée qui lui a fait donner le nom de glycérine ou principe doux des huiles.
On pourrait aussi, par une très longue trituration, opérer la même combinaison, et elle serait moins colorée, surtout si l’on employait de l’huile blanchie au soleil.
Il est important que la litharge soit pure; car si elle contenait de l’oxyde de cuivre, il serait dissous par l’huile, et lui communiquerait une teinte verdâtre.
(1) L’huile de noix se colore inoins, dans cette operation, que l’huile de lin.
VARNISH THAT CAN BE USED WHEN PAINTING.
Varnish of the Italians.
I have already made known the elastic oil, which has been prepared in Italy since time immemorial, and which has the double property of being very drying and of stopping the tendency of the most liquid glazes to run.
It is prepared by digesting it over low heat; one part litharge crushed to the last degree of fineness, with two parts linseed or walnut oil. Care is taken to stir the mixture often with a spatula to facilitate the combination.
After more or less time, depending on the amount of materials on which one operates, the oil is intimately combined with litharge, to the point that by dropping a few drops on a cold body, it immediately congeals like melted fat. If this effect does not take place, it is proof that the operation was stopped too early. It is then necessary to put the oil back on the fire and to add to it at most a tenth of very pure white wax: this is done, moreover, in all cases, to give more consistency to this preparation. When the wax is fully incorporated, the oil is poured onto a grinding stone; then, with the help of a few strokes of the wheel, the fluid part is prevented from separating on cooling, and the mixture is thus made perfectly homogeneous.
To use this elastic oil, it is diluted in mastic varnish by grinding this mixing on the palette. This forms a kind of ointment that spreads easily under the brush and remains on the painting as it is applied, without running at all: it is, therefore, very suitable for glazing.
Mixing with varnish is necessary because, without this addition, it would foam under the brush like a soapy solution, so much so that nothing could be discerned until the foam bubbles had disappeared.
This combination of oil and litharge is indeed a true soap which, except for solubility in water, has all the other characteristics of ordinary soaps formed by the union of oil and an alkali.
It would therefore be better to prepare it in boiling water, as one prepares ordinary soaps; for it is not easy to regulate the fire so that the temperature does not exceed the proper degree, while that of boiling water is always the same.
As the water dissipates through evaporation, new water is added, and when the combination is completed, the water that remains at the bottom of the vase is colorless and has acquired a sweet flavor which has given it the name of glycerine or sweet principle of oils.
One could also, by a very long trituration, operate the same combination, and it would be less colored, especially if one used oil bleached in the sun.
It is important that the litharge is pure; for if it contained oxide of copper, it would be dissolved by the oil and would impart to it a greenish tint.
(1) Walnut oil takes on less color in this operation than linseed oil.
Mérimée, J.F.L. (1830) De la peinture à l’huile, ou, Des procédés matériels employés dans ce genre de peinture, depuis Hubert et Jean Van-Eyck jusqu’à nos jours. Paris, Mme Huzard. 65–67. (Online)
The translation by W. B. Sarsfield Taylor of Mérimée’s book introduced many changes to the work. One change regarding the recipe for Italian Varnish was the amount of wax. Mérimée’s text states that the amount of wax is one-tenth of linseed oil, whereas Sarsfield Taylor’s translation, the amount is “about a sixth part of pure white wax.” The reason for the increase of wax in the formula is unclear, especially since wax did not always enjoy a beneficial reputation in oil painting.
W.B. Sarsfield Taylor’s English Translation
TO PREPARE VARNISHES PROPER FOR PAINTING
I have already noticed the strong oil prepared in Italy from a very remote period, and which possesses the double advantage of drying well, and preventing the flowing about of the most liquid glazing. It is prepared by incorporating, over a slow fire, two parts of linseed or nut oil, with one part of litharge, ground as fine as possible.1 The mixture must be frequently stirred with a spatula, to quicken the operation. The combination is completed in a longer or shorter period according to the quantity of the materials employed. This is ascertained by dropping a small quantity of it on a flag, or other cold surface, when, if it fixes in cooling, like tallow, the operation is rightly done; if not, then it is clear that the process has been stopped too soon: the oil must again be placed on the fire, and about a sixth part of pure white wax added to it. This is useful in all cases, to give a firmer consistence to the preparation. When the wax is entirely incorporated, the mixture is to be thrown on the grinding slab, and it should be ground well with the muller to prevent any separation, and to cause the parts to be perfectly united.
In using this oil, some mastic varnish must be added to it, and well mixed upon the palette. This mixture forms a soft pomatum-like substance, which flows freely in the pencil, and which remains in its place, without flowing about. It is therefore proper for glazing; but the addition of varnish to it is necessary to prevent its frothing under the brush, as it would do like soap, and this accident would prevent the work from being clearly seen. This combination is in fact a soap, which, except that it is not soluble in water, has all the other qualities of the common soap formed by the union of oils and alkalies.
It would, therefore, be better to prepare it in boiling water, as we prepare common soap; for it is not easy so to regulate the temperature of the fire that it shall not exceed the proper degree, and the heat of boiling water is always the same. As the water evaporates, more water must be added; and when the union of the materials is completed, the water remaining at the bottom of the vessel is found colourless, and has a sweetish taste. To this liquid the name glycerine (the saccharine principle of oils) has been given.
Also, by long continued trituration the same combination could be formed, which would have less colour, especially if we use oil clarified in the sun.
It is of much importance that the litharge be pure; for, should it contain oxide of copper, this substance would be dissolved by the oil, and would give the varnish a greenish tint.
1. Nut oil gives less colour in this preparation than the oil of linseed.
Mérimée, J.F.L. (1839) The art of painting in oil and in fresco: Being a history of the various processes and materials employed (translated from the French by W. B. Sarsfield Taylor. London: Whittaker & Co. 65–67 (Online)
Preparing Italian Varnish
The first part of the formula for Italian Varnish is as follows:
|Linseed or walnut oil||2 parts||60.61%|
|Litharge (lead monoxide)||1 part||30.30%|
|White wax (beeswax)||10th part||9.09%|
Finely ground litharge is added to the oil and then heated over a “slow fire.” Wax is added to the mixture if a “few drops on a cold body” does not immediately congeal. However, he recommends adding wax, in any case, to give a “firmer consistence to the preparation.”
Mérimée cautions not to heat the oil too strongly, which would darken its color; gentle heat for roughly an hour or two is typically recommended. Incorporating litharge into oil requires a minimum temperature of 150° C (302° F), causing the oil to darken like the color of coffee. In most recipes of lead siccative oil from this period, the amount of litharge generally varies from one to 20%. However, Mérimée’s formula calls for about 33% in oil. According to some sources, about one percent of litharge effectively goes into solution with oil. Excess litharge precipitates upon cooling. To dissolve the quantity of litharge in Mérimée’s recipe requires even higher temperatures and longer heating time. This amount would cause “a tallow-like grease” to be precipitated with the litharge. [48–49] This amount of litharge never entirely dissolves into the oil but forms sediment upon cooling because not all litharge goes into solution.
Litharge is typically ground in a quantity of oil at room temperature before adding it as a thin paste to the oil. The heating is started, and the oil is continually stirred while heating. The oil is heated for two hours or until the lead oxide is incorporated into the preparation. The oil is then cooled, stood for some time, and filtered.
Some recipes of this time recommend adding water before or during heating the oil with litharge. The addition of water limits the temperature and the saponification process preventing the medium from darkening. Mérimée recommends heating the oil and litharge with water to control the temperature and produce a lighter color. He describes the result of oil heated with water and litharge, saying that it forms glycerin and is lighter in color.
Mérimée writes this oil mixture is “proper for glazing,” but he recommends adding mastic varnish. The varnish preparation is described in the next section, To Make Flanders Varnish. [65–67]
|Oil of Turpentine (spirits of turpentine)||1 part||50%|
His recipe for mastic varnish makes a viscous solution. Typically, varnishes contain less than 20% resin by weight to solvent volume. Mérimée does not say how much mastic varnish to add to the oil preparation, but he says the addition “of varnish to it is necessary to prevent its frothing under the brush.” Adding mastic varnish causes it to form a soft “pomatum-like” substance, which “flows freely in the pencil, and which remains in its place, without flowing about.” He is describing a thixotropic gel that, when brushed, flows but once brushing stops, it regains its res viscosity of a gel.
Varnish and Oil as a Painting Medium
Mérimée recommended the combination of varnish and oil for use as a painting medium. This combination “gives greater brilliancy and transparency to the color and allows the production of more clear and transparent tints.” His recommendations are based on his rediscovery of the secrets of the Old Masters, particularly the combination of oil and varnish as a painting medium. Not all artists agreed with such recommendations. Jean-Baptiste Oudry (1686–1755) also believed he revealed the true secrets of the masters but advocated precisely the opposite.
In the first chapter, Mérimée offers evidence for admixtures of varnish and oil in the medium used by Renaissance artists as follows:
He claims, “the van Eycks mixed them because the idea of incorporating the two being so simple, we must infer that it would naturally, in the first instance, occur to the mind of van Eyck” and “van Eyck and his followers’ colors could not have simply been used with oil of a more or less drying quality but that they were mixed with varnish which is the cause of the surprising preservation which we witness in so many of the earliest pictures.” [6–8] These are hardly proof of the use of varnish as a medium by van Eyck in his paintings.
His second proof is that Leonardo Da Vinci used varnish in his medium. This was testified by Pope Julius II, who visited Leonardo’s studio and saw only chemical apparatus and utensils, which he understood were for preparing varnish.  Mérimée admits that Leonardo does not mention varnish in his Traité de Peinture but claims “there is no doubt as to the use of varnish” based on the description of the painting process by sixteenth-century art historian Giovanni Battista Armenini. Mérimée says he strongly advises that varnish should be mixed with colors for glazing and in those generally used throughout the painting. [10–13]
Lastly, the surest way of knowing that the earliest painters mixed varnish with oil in their medium is by consulting those regularly responsible for restoring them. Mérimée states, “We learn from their researches, that the colour of those pictures that belong to the first epoch of oil painting, are mostly of a harder body than those of a later date; that they resist dissolvents much better; and that if they are rubbed with a file, they show underneath a shiny appearance, resembling that of a picture painted with varnish.” [14–15] This observation does not provide evidence of varnishes in paint films.
Rather than proof, we read this as Mérimée’s opinion of how old master painters must have painted. For the academic artists interested in smooth, transparent, enamel-like finishes, the greater transparency, brilliance, and glazing ability provided by the combination of oil and varnish were important. There was likely some political advantage to providing this narrative. Mérimée offered Italian varnish, Flanders varnish, English varnish, and oil-copal mixtures and gave recipes for preparing each. All contained both oil and varnish.
Mérimée recommends painting with a series of thin, transparent glazes containing a large proportion of varnish. Varnishes produce a surface that the artist can easily work on and facilitates the development of smooth painting techniques. Mérimée was also aware that such painting practices produced surfaces that were not very durable. The practices advocated by Mérimée facilitated the production of the enamel-like paint films favored by the academic school.
Mérimée’s tremendous influence on French academic painting cannot be doubted. Adolphe-William Bouguereau (1825–1905), considered by most as the epitome of French academic painting, practiced techniques remarkably similar to those advocated by Mérimée. In his studio notes, Bouguereau described his method of applying a layer of viscous varnish with a stiff brush over the ground on his prepared canvases. For this layer, he used a varnish consisting of a mixture of mastic, oil, and two types of drying agents. After painting in his sketch, he fixed it with a coating of copal varnish and oil diluted with turpentine. For painting body color, Bouguereau employed a medium consisting of one part gum elemi, five parts mastic varnish, a drop or two of brown fixed oil (possibly, lead oxide cooked in oil), and several drops of a terebine.* He completed the picture by glazing with more of this painting medium, which he adjusted to contain a higher proportion of picture varnish and mineral spirits. Mérimée and Bouguereau advocated a system with layers of a varnish containing paint interspersed with an intermediate and very viscous coating over the sketch. 
In The Graphic Arts, Phillip Hamerton professes Mérimée inquiries about whether the Italians used varnish in their painting or applied varnish to their pictures only after they were completed as “a question of the greatest interest.” Hamerton describes the medium employed by Italian painters as a jelly-like medium, similar to megilp, composed of oglio cotto (cooked oil) mixed with varnish. Oglio cotto consists of walnut oil cooked with “as much litharge as it will dissolve, until it resembles the consistency of honey.” When this oil is mixed with sufficient varnish, it makes a gel that does not run off the palette. He supports the claim by citing an analysis of materials made during the restoration of a picture by Correggio. Their conclusion was Correggio employed a medium consisting of two-thirds of oil and one-third varnish. In another proof, he states Mérimée ascertained from wrinkles in a picture by Giorgione that he must have employed an oil varnish, as only “an oil varnish would wrinkle.” 
In The art of painting in oil, Mérimée explains how Pierre-Paul Prud’hon made his medium by dissolving mastic in alcohol while it was slowly heated up, which is the method for preparing Flanders varnish. Analysis of two scrapings from the paint layer in the portrait of Rutger Jan Schimmelpenninck with his Wife and Children indicates that Prud’hon used this mixture in his painting. Painting with this mixture in combination with certain dark pigments probably led to cracks in the paint layer at an early stage. However, Mérimée rests the blame for cracks in Prud’hon’s paintings as the result of not allowing paintings to sufficiently dry before applying the final picture varnish. 
The combination of oil and varnish as a painting medium remained popular among classical revivalists.  In the 1870s, the Italian artist Cesare Mussini developed recipes for such a combination, which he sold to the German company Schmincke. Even today, Schmincke’s ‘Mussini colours’ are described as ‘based on the Old Masters’ formulations.’ 
While researching oil painting mediums, Giorgio de Chirico found Mérimée’s recipe for Italian Varnish, which he called olio emplastico (emplastic oil) based on Mérimée’s French term “l’huile emplastique” to describe Italian Varnish. Sarsfield Taylor translated it into English as “strong oil.” The term emplastic, which can be found in both French and Italian vocabulary, comes from the Greek emplastikos (“suitable for shaping”) and refers to a material with the characteristics of a plaster, which adheres easily to the surfaces on which it is applied. [1573, 142] The definition of “emplastic oil” for a paint binder is not found in the literature on artistic techniques, apart from its use by Mérimée and de Chirico. The recipe used by de Chirico to make the varnish consisted of seven parts of raw linseed oil and one of litharge mixed over low heat. According to de Chirico, the advantages of this emplastic oil are that brushstrokes of diluted color do not run and can be applied immediately over another without lifting or disturbing underlying paint. The painting remembered by de Chirico as “the most complete painting I have ever executed so far,” made with this “emplastic oil,” is the Nude Self-Portrait. 
* Terebine is a siccative of various compositions, but in the late nineteenth century, it typically consisted of kauri gum melted into linseed oil, then cooked with red lead, litharge, and manganese dioxide, and finally thinned with turpentine.
Problems with Varnish Painting Mediums
Not everyone believed that Italian Renaissance painters employed a medium of oil and varnish in their pictures. A review of Sarsfield Taylor’s English translation of The art of painting in oil states:
“He lays much stress upon an “Italian varnish,” prepared, as he says, in Italy, from a very remote period: the ingredients are, nut oil, wax, and mastic. To say nothing of the wax, we conceive the mastic to be one of the worst substances that can be mixed with paint, and that it never becomes really hard, and that it is subject to continual changes; and to the use of mastic do we ascribe that separation of the paint which will perhaps pretty clearly distinguish the era of the work.” 
George Field, the nineteenth-century pigment manufacturer, was of the opposite opinion shared by other “eminent judges” that the Venetians only employed varnishes as protective coatings on their finished works and not as vehicles.  The different opinions on the Italians’ use of varnish and oil medium were lamented as a severe lack of precise information on the subject and no written records of such use during the Renaissance.
In his works, Eugene Delacroix practiced Mérimée’s method of employing a medium of oil and varnish. However, Delacroix expressed concern when working on his picture, The Women of Algiers, “of preventing the varnish underneath from being attacked when the top coat of varnish is removed at some later date.” 
From the literature on artist techniques, it is easy to see that the addition of varnish to oil paint or as isolation layers permitted the artist to construct the coveted enamel-like finishes of Neoclassical painting. However, conservation scientists caution against using varnish in paint layers, making them highly vulnerable to restorer’s cleaning solutions. 
In The Graphic Arts, Hamerton remarked that students taught by Paul Delarochre used a medium called huile grasse (fat oil), which consisted of linseed oil heated with litharge, which he said is “a hazardous vehicle, as pictures painted with it have cracked terribly.” Evidence shows Delaroche may have used a medium described by Mérimée. In a red glaze in his painting, The Execution of Lady Jane Grey, heat-polymerized linseed oil and mastic resin were found. Jo Kirby and Ashok Roy believe this indicates the use of English Varnish described by Mérimée, although this may also be attributed to Italian Vanish. The presence of resin in the painting is also suggested by the whitish fluorescence exhibited by the glaze layer in ultraviolet illumination under the microscope. 
Mérimée followed the belief of seventeenth- and eighteenth-century artists that Renaissance and, particularly, van Eyck and later Italian artists used a medium of combined oil and varnish. While artists of this period used varnish in specific passages of their paintings, such as glazes, they did not use it as a painting medium throughout their pictures. They also did not interleave layers of varnishes in their paintings, which Mérimée and his contemporaries endorsed.
Biography of Jean-François-Léonor Mérimée
According to the 1839 English translation of the treatise, Mérimée was Secretary to the Royal Academy of Fine Arts in Paris. He trained as a painter with Doyen and Vincent, traveled to Rome, and became a professor of design at the École Polytechnique. Mérimée’s treatise shows interest in the history of painting, chemistry, and color theory. It discusses the materials and techniques of earlier painters (Van Eyck, Veronese, Rubens, Reynolds, etc.) and provides practical advice and recipes for contemporary painters. The treatise contains an elaborate discussion of preparatory layers employed historically and around Mérimées time. He includes his ideas on what types of grounds painters should use.
- Mérimée, J.F.L. (1839) The art of painting in oil and in fresco: Being a history of the various processes and materials employed (translated from the French by W. B. Sarsfield Taylor. London: Whittaker & Co. (Online) See also Mérimée, J.F.L. (1830) De la peinture à l’huile, ou, Des procédés matériels employés dans ce genre de peinture, depuis Hubert et Jean Van-Eyck jusqu’à nos jours. Paris, Mme Huzard. (Online)
- Williams, W. (1787) An essay on the mechanic of oil colour. Bath, England: W. Williams. 48–49.
- Swicklik, Michael (1993) “French painting and the use of varnish, 1750-1900.” Studies in the history of art. Washington, D.C. Vol. 41. 157–174.
- Hamerton, Philip Gilbert (1882) The Graphic Arts; A Treatise on the Varieties of Drawing, Painting, and Engraving in Comparison With Each Other and With Nature. Boston: Roberts Brothers. 272–273.
- Van Zuien, Eva. (2012) “A Family Portrait in Silver Grey: The Intriguing Painting Technique of Pierre-Paul Prud’hon Revealed by the Restoration of the Portrait of ‘Rutger Jan Schimmelpenninck with His Wife and Children’ (1801-02).” The Rijksmuseum Bulletin 60, no. 3 (2012): 194–211. http://www.jstor.org/stable/41703570. 205.
- Grand Larousse de la Langue Française in six volumes, volume II, Librairie Larousse, Paris 1972, 1573; S. Battaglia, Great Dictionary of the Italian Language, vol. V, UTET, Turin 2004. 142.
- Knirim, F. (1839) Die Harzmalerei der Alten. Berlin: Fleischer. 168–186.
- Cesare Mussini—famous painter and guardian of the old masters’ formulations. Schminke Company Website (Online) (accessed December 2022).
- Vacanti, Salvatore (2010) “Dalla Pittura Murale All’olio Emplastico: Sviluppo E Diffusione Delle Ricerche Tecniche Di De Chirico Tra Anni Trenta E Quaranta.” Metafisica 2010 No. 9/10. 181–182.
- Mérimée on Oil Painting. Blackwood’s Edinburgh Magazine, Vol. XLV, June 1839. 748.
- Delacroix, Eugene (1932) Journal de Eugene Delacroix, ed. Andre Joubin, 3 vols. (Paris, 1932), 27 June 1854, Vol. 2:206.
- Schroder, Anne and Cox, Ruth Barach (2008) “A Newly Discovered Early Painting by François Gérard.” AIC Paintings Specialty Group Postprints. Vol. 20 (2008). 50.
- Kirby, Jo, and Roy, Ashok (1995) “Paul Delaroche: A Case Study of Academic Painting. Historical Painting Techniques, Materials, and Studio Practice.” Preprints of a Symposium, University of Leiden, the Netherlands, 26-29 June, 1995. 172.
- Manguta, Cristian (2010) “The XVII-TH Century’s Thixotropic Painting Medium—II The Old Flemish School Gels and Their Reconstruction Following Rubens and Van Dyck’s Recipes.” Journal of Science and Arts Year 10, No. 1(12). 191–198.
Rublev Colours Italian Varnish
In 2010, we reconstructed mediums described by Mérimée in The art of oil painting. We did this to understand the properties of the mediums used by so many artists of the nineteenth century and presumably earlier. We also examined reconstructions made by Leslie Carlyle and other researchers.  We found resinous varnishes in paint layers, such as mastic and dammar, make the painting more susceptible to solvents used to apply a final varnish to the painting and later to clean the painting. Wax also does not form hard paint films because it is a soft solid readily soluble in common solvents used to clean pictures.
The varnishes described by Mérimée result in transparent and smooth paint films highly desired by French academic painters. How do we achieve these properties in a medium without the disadvantages of resinous varnishes? By 2013, we recreated Italian Varnish with significant improvements to the method and materials given in the recipe by Mérimée. The amber gel medium of Rublev Colours Italian Varnish has the same properties as Mérimée’s Italian Varnish without incorporating mastic resin and beeswax. Instead, Rublev Colours Italian Varnish used hydrogenated castor wax and fumed silica in small amounts to provide a thicker painting consistency and faster drying time to linseed oil.
Like Mérimée’s Italian Varnish, Rublev Colours Italian Varnish consists of linseed oil heated with litharge. Many nineteenth-century “black oil” recipes contain excessive amounts of lead oxide. We made ladder tests of various amounts of lead oxide in oil and found an amount that provides the best properties without precipitating lead oxide.
Rublev Colours Italian Varnish sets quickly while providing transparency and firmer consistency to oil colors when mixed with them in glazes. In addition to the soft sheen of the medium, the artist now also has the means of more rapid execution. Artists can add Italian Varnish to their colors to add transparency without increasing the flow of colors added to passages in paintings.
Where to Buy Italian Varnish
William Winsor first patented the paint tube syringe in 1840 (Patent No. 8394) to replace bladders for storing paint.
Limited historical edition of Rublev Colours Italian Varnish in a glass syringe.
Natural Pigments introduces a new oil painting medium called.