Al Fresco vs al Secco and Controversial Examples of Murals

Yet before I started my studies of art history I had got problems to accurately recognize a technique applied by artists in processes of mural painting. Although people generally describe wall paintings simply with the term of frescoes, it may not be technically correct for all of them (Jaspal 2007). Then I actually realized that even scholars may happen to misuse the term, especially in case of controversial examples, whose technique has been always strongly debated.

But let’s start from the beginning

When we talk about wall paintings or murals (Latin murus) we mean paintings done on the walls (Somathilake 2007:109). In the context of techniques of murals, we can specify:

AL FRESCO (It. ‘fresh’) True fresco (buon affresco, as distinct from fresco secco), is painting done with mineral or earth pigments upon wet lime or gypsum PLASTER. (Vegetable pigments cannot be used as they are attacked by the lime). The pigments are suspended in water, and unite with the plaster as they dry. The basis is a roughcast wall, covered with a layer of plaster (the arricciato), on which the composition (the synopia) is sketched out in charcoal and sinopia. Only enough wet plaster (the intonaco) is then applied for a day’s work. Any additional retouching must be done in fresco secco.

(Lucie-Smith 2003:96)

Michelangelo Buonarroti (1475-1564). ‘Sistine Chapel Ceiling, 1508-12 and ‘Last Judgement’ 1536-41 (fresco). True Fresco is a skill that dates back to Classical Antiquity but reached its peak as an art form during the Italian Renaissance. Photo source: Get Your Guide (2008-2020). “Private Early Morning Sistine Chapel Tour.” In: Get Your Guide.

And …

AL SECCO (It. ‘dry’), fresco secco (It. ‘dry fresco’) Painting which, unlike true FRESCO, is carried out on plaster which has already dried. It can be done in TEMPERA, or with PIGMENTS in a MEDIUM of lime-water. In the latter case, the surface is dampened before applying the paint. The results are less durable than true fresco.

Lucie-Smith (2003:195).
Cupola decoration Inv. No. 7118 Tempera; Bawit, Monastery of St. Apollo, 6th / 7th century (Coptic Museum, Cairo, tempera). Photo source: Emil Krén and Daniel Marx © Web Gallery of Art.from Web Gallery of Art (1996-2020).

Al Fresco – from the Antiquity to Renaissance

AL FRESCO (fresh in Italian) indicates fresh or wet ground, and FRESCO BUONO (true fresco) is made using a genuine wet ground (Somathilake 2007:109). Although al fresco had been already practiced by ancient civilisations, the technique called fresco buono (or buon fresco) was first perfected in Italy, around 1300, on the verge of Renaissance (Ibid.:110).

Michelangelo Buonarroti (1475-1564). ‘The Creation of Adam’ from the Sistine Chapel Ceiling, 1508 -1512 (fresco) The most iconic image from the Sistine Chapel ceiling, also referred to as ‘The Creation of Adam’. Public domain. Photo source: “Fresco” (2020) In: Wikipedia, the free Encyclopedia.

“The technique [actually] involves the most durable form of art known to Europe where a piece of painting must be completed on a wet and freshly laid stucco ground before another piece of plaster is prepared” (Somathilake 2007:113). In this method pigments are mixed with water only (Lucie-Smith 2003:96). In a fresco technique, “no binder is required to be added to the mineral pigments that are applied because the chemical reaction of the wet plaster with the carbon dioxide in the air creates a hard layer of calcium carbonate and the pigments are securely fixed in the calcium carbonate layer while drying” (Jaspal 2007).

Young Girl Gathering Saffron Crocus Flowers, detail of wall painting, Room 3 of House Xeste, Akrotiri, Thera. Second Palace period, c. 1700-1450 BC., Thera. Public domain. Source: “Wall Paintings of Thera” (2020) Wikipedia. The Free Encyclopedia.

Accordingly, the method “consists of painting with lime-resistant pigments (only pigments which do not suffer from lime can be used) on damp lime plaster, which has not yet set. In this process as the plaster can only be painted on once it is wet, the painter divides his work in the so-called ‘day-pieces’, each piece day being the area, which he can finish [daily]” (Somathilake 2007:113). “In this rapid process, the parts of the plastered portion that have not been painted yet need to be cut away at the end of [work]” (Dhanapala:65). When the artists comes back to painting, the surface is plastered to keep it damp (Ibid.). “Thus in true fresco nothing can be added or altered after the plaster has set. This time factor gives fresco painting an extraordinary vitality as it means that the brushwork must be quick, the forms monumental and the range of colours limited”(Somathilake 2007:113).

“In addition, when the plaster sets, the particles of colours crystallise into the wall and remain permanently fused in it. They cannot flake off. […] The fresco can only be damaged if the wall decays. (…) The relevant plaster layers must therefore be very carefully built up” (Ibid.).

The Minoans decorated their temple (known as palaces) complexes and homes with the so-called true fresco painting (buon fresco). Bull-leaping fresco from the east wing of the palace of Knossos (reconstructed), c. 1400 BC, fresco. Archaeological Museum of Heraklion, photo: Jebulon, CC0. Public domain. Photo and caption source: Dr Santa German, (2020). “Bull-leaping fresco from the palace of Knossos”. In: Khan Academy (2020).

The technique of Al Secco and Tempera

Fresco secco actually indicates any dry technique of murals, including tempera. Here, “the whole wall or rock surface may be completely plastered and allowed to dry” (Dhanapala:65). The main aspect of this method, involves then painting on lime plaster which already has set (Somathilake 2007:113). The technique al secco was commonly applied in antiquity (Somathilake 2007:113). In its process, “the pigments were ground in an aqueous binding medium. The completely dry lime plaster wall is usually thoroughly saturated with lime water (or baryta water) and left overnight. The painting then takes place on a moist surface as in fresco, except that the colours are mixed with a solution of casein glue or egg yolk [- tempera], instead of being ground in water only” (Ibid.). Painting in fresco secco “are also quite stable, but susceptible to damage by moisture and dampness. Yet, as they are done on dry plaster, there is no stress of the time deadline” (Jaspal 2007). This technique has always complemented the fresco method, when alterations were needed. These are usually referred to as superficial, upper layers (ibid.).

TEMPERA (It. fr. Lat. temperare, ‘to mix in due proportion’). An EMULSION used as a MEDIUM for PIGMENT. Traditionally, tempera is made with whole eggs or egg-yolk, but milk, various kinds of glue or gum or even dandelion juice or the sap of the fig-tree can be used.

Lucie-Smith (2003:213).

In other words, the pigment used is mixed with some liquid vehicle, such as egg-yolk, diluted glue or gum, chalk, clay, gelatine, etc. (Somathilake 2007:109-110,112,120). Next it is laid on a dry surface. After Somathilake (2007:120), however, true tempera is when the colours are ground with egg yolk only. Another characteristics typical of tempera are rather opaque colours in paintings, whereas in the true fresco technique, colours are subdued and their choice is limited (Dhanapala:67).

It is important to note that tempera in al secco technique is exclusively used in wall paintings, when a painting is applied directly on plaster (the latter is applied first on the wall or rock’s surface). Tempera, however, can also be executed on the wood (e.g. fayum portraits), vellum (e.g. The Beautiful Hours of Jean de France, Duc de Berry), paper (Funerary Equipment, Tomb Of Userhat), canvas (paintings in the Church of Debre Berhan Selassie in Gondar), etc.

Wall painting flourished in Faras in the tenth and eleventh centuries. The finest monumental composition is the Nativity, once in the northern aisle … Photo source: the shot from the documentary by Jurkow, W., Manowski, R. ((2014). FARAS 3D. “Katedra nad Nilem”. [“Cathedral by the Nile”]. National Museum of Warsaw. In: Youtube.
…. and the Three Youths in the Fiery Furnace in the narthex. The paintings were executed in the tempera technique on dry mud plaster, using natural pigments found on the desert fringes of the Nile Valley. Photo source: the shot from the documentary by Jurkow, W., Manowski, R. (2014). FARAS 3D. “Katedra nad Nilem”. [“Cathedral by the Nile”]. National Museum of Warsaw. In: Youtube.

Major difference between the techniques

Accordingly, the main difference in these two methods is that in the fresco the pigments are strongly bound within the plaster and so are united with the surface, while in al secco the pigments are applied as layers on top of the plaster surface (Dhanapala:65; Somathilake 2007:114).

Controversy in the matter of the Technique of Murals in South Asia

Controversy regarding a recognition of a correct technique of murals mainly appears in an analysis of paintings from South Asia, precisely Ajanta (India) and Sigiriya (Sri Lanka). Let’s call them simply paintings. The paintings of Ajanta Caves and of Sigiriya rock are said to have been created between the fifth and seventh centuries (Dalrymple 2014; De Silva 2019). Most of experts have already reached a consensus that the so-called Ajanta ‘frescoes’ are actually paintings made by means of some kind of tempera, which actually amounted to the title of al secco as their pigments had been applied to dried plaster (Somathilake 2007:120). Nevertheless, the case of Sigiriya still keeps the scholars awake.

Dancer with her attendants and musicians around her, mural painting in Ajanta caves. Photo and caption source: Baani Sekhon (2020). “Shades of Indian Women in the Art World”. In: Baani’s Art Point.

Differences between murals of Ajanta and Sigiriya

One of Sri Lankan authors, D.B Dhanapala heatedly states that even “most authorities incline to the opinion that [Sigiriya paintings] are tempera in technique, [their] reasoning seems to be this wise: ‘[the] Sigiriya pictures bear a close affinity to those at Ajanta. [As the latter] have been proved to be tempera paintings, therefore the Sigiriya figures are tempera [too]!” (Ibid.:64).

There are several aspects of murals that can be actually examined in order to decide on a technique applied: characteristics of the ground (plaster), the presence of medium and its nature (Somathilake 2007:119).

Women in the Clouds in Sigiriya: true freso or tempera? Photo by Agnieszka Szkarłat. Copyright©Archaeotravel.


As it is discussed above, a medium binder has been ultimately used in al secco technique, usually by means of tempera. The universally accepted classification of paintings, such as oil, watercolour, tempera, fresco etc. is generally formulated based on the medium (binder) used (Ibid.). Unfortunately, the binding medium in India and Sri Lanka is said to have largely perished due to autoxidation and the depredations by insect-pests (Ibid.:119-120). Hence there is an issue of identifying the presence of the binder even through chemical analysis, which factually stands in the way of coming to a definite conclusion (Ibid.:120).

One of the most iconic Sigiriya’s murals ; the so-called Apsara or a court lady. Photo by Agnieszka Szkarłat. Copyright©Archaeotravel.

Dr. Somathilake (2007:120,123), however, underlines that “in many murals [vegetable glue or gum] was the only organic binding medium that held the pigments firmly to the ground unlike in the fresco method. Thus, all these facts would definitely point to a tempera technique at Ajanta and elsewhere.” The binding components of the Sigiriya pigments are said to be a vegetable gum and a drying oil, which is insoluble in water (Ibid.:124). Probably, this is why the murals, which were exposed to the elements for centuries, have eventually survived to our times (Ibid.). From literary documents, we also know that ancient artists of Sri Lanka were familiar with a technique of using an oil medium for wall paintings (Ibid.)“and there was an apparent reason for using [it] since almost all of the murals were located outdoor, unlike the painting sites of India” (Ibid.).

Ground for the murals

In further examination, Dhanapala also analyses the ground for the murals in both cases, Ajanta and Sigiriya. The proper thickness and composition of the plaster at Sigiriya, unlike Ajanta’s thin surface, was actually more prepared for the technique of true fresco (Dhanapala:65-66). Moreover, artists working in Ajanta Caves must have worked in dimly-lit halls (Ibid.:66)(the way they actually let the light in is another mystery) and so they probably were not able to complete such intricate compositions, as Ajanta boasts, before the plaster got dry (Ibid.). Sigiriya’s painting have got more simple compositions and they are located in the open rock pocket, where strong sunlight has been available (Ibid.) (a separate question is how the artists actually managed to paint on the rock surface, while being suspended at the height of over 50 meters above the ground (Kovalsky, V. 2013).

The proper thickness and composition of the plaster at Sigiriya was more prepared for the technique of true fresco. Photo by Artur Maltsau (2015) Free images at Pixabay.

Pigments used

Furthermore, the author observes that in case of Ajanta, the scenes are overpainted in many scenes, whereas at Sigiriya, there are only few examples of overcoating (Dhanapala:67). In comparison to Ajanta, where colours are deeper and their palette wider, at Sigiriya the pigments are much thinner and so subdued, and they are restricted to mainly red, yellow, green and black (Dhanapala:67; Somathilake 2007:121,123). Although there are small areas of more intense green and blue, the author suggests, they may have been later additions completed in tempera (Dhanapala:67). Dr. Somathilake (2007:121), however, argues that although the blue pigment was not actually used as much as the other colours, it is evident that the green was originally applied in Sigiriya murals and so it was not a later addition. He also underlines that all the pigments used were of natural origins. In a fact, organic pigments were typical of both, fresco and tempera techniques.

Ajanta caves Mural paintings- Flying Apsara (Left), Queen Sivali begin tended to by her maids (Right) . Photo and caption source: Baani Sekhon (2020) . “Shades of Indian Women in the Art World”. In: Baani’s Art Point.

Besides, Dhanapala points out to the fact that the pigments in tempera have got a tendency to peel off on the plaster, which happens at Ajanta but does not occur at Sigiriya (Dhanapala:67). Even though the plaster comes off in Sigiriya murals, the pigments stay strongly incorporated in its structure (Ibid.:68). And if paint peels off, it appears only on surfaces, which were later altered in tempera (Ibid.).

Sigiriya woman with two hands

Dhanapala then puts forward another argument to support his thesis. In the figure no. 8 of the pocket B, behind the woman’s right hand, which was altered, there is an outline of the original hand visible in the plaster (Dhanapala:67).

Mural showing the woman with the outline of the original hand and the altered one below. The artist must have changed his mind … (Image modified from the original – the size reduced). Photo source: Jenny Rainbow (2020). In: Fineartamerica.

Dhanapala came to the conclusion that the artist changed his mind about how the woman’s hand should be actually depicted “but before he had time to erase the original hand the plaster dried” (Ibid.). Dr. Somathilake responds to Dhanapala’s argument claiming that an examination of the painting does not show any attempts to erase the contour of the original hand (Somathilake 2007:120-121). Moreover, if the plaster had dried before the artist had time to erase the hand, he would not have enough time to finish the hand in the altered position (Ibid.). Simultaneously, the scholar assumes that both: the original version and its alteration would have been done in fresco. There is another option though. The original woman’s hand may have been made in a true fresco technique, and later her hand was altered with a tempera technique. That would actually explain how the artist had enough time to finish the altered version and also why his original idea was still visible in the plaster.

Compromise ?

In his conclusion, Dhanapala sustains his arguments and claims Sigiriya murals were originally made as real frescoes (Ibid.:68). On the other side, such authorities, as Dr. Somathilake, strongly disagree with that opinion and argue that using the term ‘frescoes’ in terms of Ajanta or Sigiriya murals “is a misnomer in every sense” (Somathilake 2007:124). Further, they emphasize that there is no evidence that the Asian wall paintings are real frescoes (Ibid.), and “the general technique of the murals of India and Sri Lanka has always been some kind of tempera” (Ibid.). On the other side, there are scholars who have reached the compromise in that hotly debate and they believe that a technique applied in Ajanta and Sigiriya may be actually a combination of real fresco with tempera (see Somathilake 2007).

Notable Mural painting in Ajanta caves called Black Princess . Photo and caption source Baani Sekhon (2020). “Shades of Indian Women in the Art World”. In: Baani’s Art Point.

“No known process …”

Finally, it is also worth to quote another scholar, Havel (1905) whose words have become prominent for many researchers investigating the matter of Sigiriya’s murals (Dhanapala:66).

“There is no known process of tempera or oil painting which would stand to exposure of tropical weather for nearly fifteen hundred years as the Sigiriya paintings have done.”

Havel (1905). In: Dhanapala:66.

We can also conclude that, like many aspects of Sigiriya site (see: In the Realm of Demon Ravana), also the question of its paintings (aka frescoes) still remains unsolved, not only in terms of their technique of painting but also regarding the way they were executed, iconographically represented, and the purpose they were made for at all.

Featured image: Dancer with her attendants and musicians around her, mural painting in Ajanta caves. Photo and caption source: Baani Sekhon (2020). “Shades of Indian Women in the Art World”. In: Baani’s Art Point.


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