The Transition From Egg Tempera to Oils
The Transition From Egg Tempera to Oils
It is difficult to place the origin of tempera painting into a specific timeframe. We know of examples that date as early as the first century AD, but due to the lack of accurate or methodical historical records at the time, we are unable to establish a progression of its emergence as a consistent painting technique. The earliest written account we know of is that of Pliny, who lived from 23-79 AD. His account speaks of egg tempera as a technique that—when varnished— has a high durability; this implies that there had been much experimentation beforehand, which sets the technique’s origin to a time earlier than Christ. We also know that Zeuxis, Parrhasius, and Apelles were all in support of tempera painting. In Pliny, we also find an account of atramentum (synonymous for black). Jacques Maroger will also speak of this black oil in accordance with the techniques of artists such as Antonello da Messina, Leonardo da Vinci, Giorgione, Titian, Tintoretto, Rembrandt, Rubens, and Velazquez.
If we jump forward to the next written account of drying oils, we come to the fifth century Greek writer Aetius. He speaks of cicinum (castor) oil, linseed oil, and walnut oil as siccative oils. The first two are associated with medical writings while only walnut oils are associated to art at this point. There are plenty of references to drying oils within medical and technical manuscripts ranging throughout the post-Christ era. Pliny, Aetius, Dioscorides, Hippocrates, the “Mappae Clavicula [Key to Drawing]," da Vinci, van Eyck, all speak of consistent research of drying oils throughout history while Muratori, the Manuscript at Lucca, Eraclius, Theophilus, and the Byzantyne manuscript (lately edited by M.M. Didron and Duranol) speak only of glutinous mordants.
There is general consensus about how tempera came to be understood as a conventional technical means to achieve a satisfactory visual result: Cimabue adopted the technique (as established in the 12th and 13th century manuscripts) from the Greeks in 1250 (according to Vasari). He later taught the method to Giotto, who taught it to Agnolo Gaddi, who, in turn, was Cennino Cennini’s teacher. It is in Cennini’s “ Il Libro dell’Arte” that we can place the technical and conceptual development of Art emerging from the Middle Ages into the early Renaissance. He centralized the methodical deconstruction so representative of Western civilization. It is in his handbook where we understand the importance that tempera holds for the Italians, but it is also where we can see the first attempts of the Italian artists to conceptualize the technical discoveries which were happening in Flanders at the time. When seen in hindsight, it is easier to grasp the facility with which the Northern artists grasped the technical aspects of the craft much more efficiently than the Southern artists. One of the major concerns for tempera paintings was the excess humidity which complicated their siccative process and destroyed them in very short periods of time if not properly protected by varnishes. It is no surprise that these varnishes were refined to unsurpassable degrees by the Flemish and renounced by the Italians whose warm weather would allow proper drying and setting of the color surface.
Cennini writes about how to work in layers in order to exploit the properties of tempera paint through a 3-color system. We see a convention for painting (which can now be justified through optics) in the system of green-and-white modeling of the figure; a painting is begun with a green underpainting which will later be neutralized by the reds and modulated by the yellows to come. We are told to divide every color we will use into three plates and work them into three separate values: light, medium, and dark. These are then worked with on top of the green underpainting. We can understand the practical usefulness to the craftsman of such a convention for a technique which, almost exclusively, allows gradations through hatching. It becomes easier to compartmentalize the process of working shadows, mid tones, and lights, freeing the artist up to focus more energy on the creative impulse instead of focusing on the mechanical aspect of the craft. The only way to overcome the need for hatching in tempera is through an arduous system of soft, transparent staining (akin to glazing). The work has to be built up through a progressive set of interlocking stains which, through optical mixing and complex neutralizing and heightening of effects by one color on the other, creates a beautiful, softly transitioning and highly refined image. The artist in whose work we can most clearly see this system is Botticelli. If we study his figures closely and contrast them with his environments, we can detect both systems of tempera painting at play.
The glazing system in tempera becomes so demanding and has the danger of coming off the surface completely if not worked with the proper care and softness that we begin to grasp the reasoning behind the adoption of oil painting as a medium of choice by Renaissance artists. Oil painting allows for soft (almost imperceptible) transitions which are closer to the transitions we see in nature, with the only initial drawback of the time it takes to be ‘dry’ to the touch; this is only a relative drawback because it also allows the artist more time to refine the image. The opportunity to reenact the play of light on form more closely than was ever before possible accounts for the displacement of the tempera technique, although some of the most successful artists never fully removed it from their repertoire of techniques. We see artists such as Dürer, Rembrandt, Velazquez, Reynolds, da Vinci, and Rubens using a mixed technique for their works. I also have reason to believe that the Chardin paintings in the Metropolitan Museum of Art are executed with a mixed technique. I believe they exhibit marks that are reminiscent of a heightening, fast-drying medium (used for underpainting and final strokes) made of egg-yolk, oil, and lead white. The paint applied on top of this medium slides off it in a very peculiar way which is different to the lack of drag we see in an underpainting done completely in oil. I have successfully experimented with mixed technique in the past and, after keeping track of paintings done in between the time I executed these experiments and the present, have noticed that these have been the most stable ones in terms of color, structure, and brilliancy. Another aspect which calls for the use of this technique, is overcoming the necessity to varnish, which was another major reason for the transition from tempera into oil painting.
The varnishes used to coat paintings were most commonly composed of hard resins cooked at high temperatures into siccative oils. The first instances of these varnishes were seen in Greece: the Greek army’s fleets were protected from water by encaustic (resin and wax) and varnishes. The Greek marble sculptures, which we have come to accept as cold stone images, were in fact painted with encaustic and turned into colorful icons. We know from early writings that the only movable pictures produced by Greek artists were done in encaustic and tended to be either polished or varnished in order to achieve the glossy surface. The only logical explanation of why the oleo-resinous vehicle wasn’t pushed further in its technical evolution within Greek society is the advent of egg-tempera painting. This technique offers a very versatile range of effects built up through hatching; once a tempera painting was completed (usually at a brighter tonal range than was intended for the final image), it was varnished with a reddish/brownish varnish (a variation of the original atramentum), giving the picture a unifying effect in the harmonization of hues. We can observe a carry-over of this technical necessity within the painting of the Flemish school (more so in the Baroque than in the Renaissance). By the time the Renaissance was in its full strength, artists had discovered how to purify and clarify oils and resinous vehicles to a higher degree, which allowed them to use tempera as a simple, hatched underpainting (or drawing), and apply very complex varnishing coats with a mixture of varnishes and opaque or transparent overpasses without affecting the brilliancy of the underpainting or the hues of subtle colors or tints. This allowed for an optically complex and highly planned layout of color, tone, value, and form. The high gloss (smooth) finish became a convention for quality because artists in Northern Europe associated the tightly packed hydrofuge surfaces with durability and stability. Another factor which played an important role in the use of oleo-resinous vehicles was the “locking up” of light-sensitive/atmosphere-sensitive colors. If a lake tint or a fugitive color is locked up inside a high quantity of resin, it becomes protected from external influences, effectually turning it more permanent.
It was Antonio da Messina who moved from Italy to Flanders in search of the “new knowledge”. He went searching for the “inventor” of the new technique: Hubert van Eyck, a well-respected, admired, accomplished artist in Flanders and, once he learned everything he could from van Eyck, he returned to Italy to produce work in the new technique. He soon realized the resinous ingredients weren’t needed in a climate like Italy’s which was milder and more stable. It was only in Northern Italy where it remained necessary to incorporate such materials into the paintings or to give them a final coating with varnish. This accounts for the matte look of Southern Italian paintings when compared to the high gloss of Northern Italian or Flemish paintings.
The new technique was adopted rather slowly by the Italians. Tempera had been held up in such high esteem throughout the centuries that artists were not willing to let go of such a prized and proven technique. As we know, tempera was in itself a medium fit for complex expression. Frescos were touched up with tempera in order to be able to bring wall paintings into a higher level of finish as well as allowing the use of colors which were chemically incompatible with limestone. We know of many samples of casein tempera used for this purpose. The Italians would not easily let go of a technique which yielded such beautiful results. A clear example of this refusal to fully accept the new technique is Ghirlandaio: he has two pictures in the Berlin Gallery which are executed in a combination of tempera and oil (one figure done in oil and the rest in tempera). These pictures are demonstrations on the technical transition between both artistic worlds. They were most likely technical experiments performed by the artist in order to test both materials alongside one another. Even Raphael’s training consisted of tempera painting: if one looks closely at his early works, we can identify a hatching technique which is invariably consistent with painters trained in this medium.
The van Eyck brothers are generally attributed with the invention of oil painting, but this is a gross oversimplification of a complex technical development caused by the pressures of history and climate. We can safely say that it was they who used the material in a way which had never been applied before and refined the formulas to a level which would yield beautiful transitions while retaining full chroma, allowing transparency and opacity, different styles of blending, and superseding the need for a final varnish. This conceptual and technical development allowed them to bring oleo-resinous coats into the painting earlier (and with a higher level of complexity) than had ever before been possible. This development also eliminated the need to varnish a painting in the full force of sunlight (the only way to make their thick varnishes malleable) which would sometimes cause the panels to split at the unions. This is said to have happened to Hubert van Eyck and to have been the reason for his research into oleo-resins to take the turn it did.
Two of the major technical developments for the adoption of oil were: 1) the addition of litharge as a siccative and chemical stabilizer for the coats; 2) the understanding of refining oils in order to reduce the mucilage and the sun-thickening of these oils (which begins the process of polymerization). This allowed for a cooking of the (purified) resins into the oil with less carbonization of organic matter happening, therefore reducing the darkness of the oleo-resinous vehicle produced. Once these two elements were combined, it was only a matter of slight modifications to the formula that allowed a wide range of materials to be produced, e.g.,: use of walnut oil for the lights, blues, and greens; use of linseed oil for shadows and mid tones. The Italians defined the different varnishes as: ‘vernice liquida’ (sandarac varnish), ‘vernice d’ambra’ or ‘vernice liquida gentile’ (amber varnish), and ‘vernice chiara’ (mastic or bleached fir resin— sometimes both— and nut oil). As the use of oils was assimilated and Italian technique developed, we encounter a paint which becomes leaner through refining processes. We see it especially in da Vinci: he refined walnut oil to its leanest possible version in order to obtain a clear medium which would dry fast, retain brilliancy, allow for multiple layerings and still maintain the flexibility of oil painting.
It’s interesting to study how the highest levels of Italian Renaissance painting sought to return to a faster-drying, lean liquid (closer to their esteemed tempera painting) that would retain the high viscosity of a semi-polymerized oil without the drawback of excess mucilage. This seems to be a natural progression of the technique due to the necessity of raw linseed oil (with its full load of mucilage and higher acidity) for grinding pigments. It is essential to have the higher pH of this oil in order to maximize its pigment-wetting property while mulling one’s own colors. It is also interesting to note that neither the Flemish nor the Italians completely moved away from tempera. It was discovered that a methodical layering of tempera, then oil, then oil or resin tempera, then more oil, etc, allowed for a brilliance to happen from within the layers of paint. The refraction of incoming light is stopped at various levels within the coats of oil by the white tempera used to bring back the lights between oil glazes. We see the same progression and discoveries happening in Spain and England, though with different aesthetic aims. The most flamboyant examples of the use of this technique happen in England, France and Spain in the hands of artists such as Velazquez, Reynolds, and Chardin.
Art technique and aesthetic values are inseparable from History. The human condition, the contextual values, and technological advances define the path taken by artists and researchers in the search for a fuller mode of expression. Humans are afraid and distrustful of the new, we glorify the old, and inevitably end up with a chimera of both worlds, most of the time creating greatness and carving out History itself from the foundations of this chimera. This is the closest we can come to an explanation (short of a painting demonstration) for the results of this vibrant time within the History of Painting. Our understanding and knowledge of the art and craft of painting must keep developing and the search for an ever-improving technique and mode of representation must be sought relentlessly if we are to leave a mark (which should last far into the future) in the in the arts of our times. Perfection of craft and concept; balance of context and History: this is the crux where artists must operate from and from which they will develop a marked fluency within their language. It has always been a love for knowledge and craft which has marked the greatest artists in History, and it should be the minimum requirement in today’s world, especially with the booming impact of the Information Revolution on the exchange of knowledge among peers. We artists would be glad to feel an increase in the fluency of information pertinent to our crafts.
Works Cited
Cennini, Cennino. The Craftman’s Handbook (Il Libro dell’Arte). New York, New York: Dover Publications, Inc, 1954. Print.
Doerner, Max. The Materials of the Artist & Their Use in Painting. New York, New York: Harcourt, Brace and Company, Inc, 1934. Print.
Eastlake, Sir Charles Lock. Methods and Materials of the Great Schools and Masters, Two Volumes Bound as One. Mineola, New York: Dover Publications, Inc, 2001. Print.
Maroger, Jacques. The Secret Formulas and Techniques of the Masters. New York and London: The Studio Publications, Inc, 1948. Print.
Mayer, Ralph. The Artist’s Handbook of Materials and Techniques. New York, New York: The Viking Press, 1962. Print.
The Metropolitan Museum of Art, New York, New York. Chardin, Jean-Baptiste-Siméon. Soap Bubbles. New York, New York. 15-07-2011
The Metropolitan Museum of Art, New York, New York. Chardin, Jean-Baptiste-Siméon. The Silver Tureen. New York, New York. 15-07-2011
Wehlte, Kurt. The Materials & Techniques of Painting, With a Supplement on Color Theory. New York, New York: Van Nostrand Reinhold Company, 1982. Print.
Vasari, Giorgio. Lives of the Artists, Volume I. New York, New York: Penguin Group, 1987. Print.