Jan van Eyck and the Flemish Technique of Oil Painting in the Fifteenth-Century
The Flemish artist, Jan van Eyck, was the most influential in oil painting technique. In fact, he introduced different oil painting techniques in Europe and exploited the versatile benefits of oil paint through different types of mediums. The Flemish artists are also remembered for realistic observations and descriptive effects created by oil paint. We will focus here on how the pigments were mixed with oil, how the main colours were used in the painting, and wood as a medium for oil in respect to the fifteenth century Flemish art. We also discuss here how the oil painting technique was used in two masterpieces of Jan van Eyck. The Arnolfini Portrait and Adoration of the Mystic Lamb.
In the painting, the Adoration of the Mystic Lamb (Figure 1), the four groups of saints, prophets, popes, martyrs, and virgins are converging to the central altar, where the lamb is being sacrificed. The lamb is adored by the angels. This short essay will focus on how the pigments were mixed with oil, how the main colours were used in the painting, and wood as a medium for oil in respect to the fifteenth century Flemish art.
The Flemish painters used different pigments for different colours. The pigments were mixed with oil. Oil paint was transparent and can
be used through layers. The artists used azurite for red, orpiment for yellow, and ultramarine for blues. The lower layer painted first with white or grey. Jan van Eyck’s Arnolfini Portrait was done in this technique. It can be assumed the same thing happened with the Adoration of the Mystic Lamb. Probably, they did the same with red portions of the painting. Red colour used in the robes of the papal saints (Figure 2), the altar, and the standing prophet (Figure 4). In the fifteenth century, artists used vermillion in the lower layer, then red lakes on the upper layers. Sometimes they used red lakes over vermillion or azurite to produce different red. The red lakes were fully translucent with oil and could produce more variations. Van Eyck used red lakes over azurite to make purple of the popes. Red lakes were not gritty so the painter easily used red lakes in a lot of places. Other saints were drawn with much cheaper earth brown pigments in that time.
The Flemish painters used copper green to paint green. In the background of the Mystic Lamb, the field, hills and trees were painted in glowing green. It was translucent within oil as red lakes. Some other pigments like yellow and orpiment were opaque. Golden-yellow is used at the top of the painting on the rays of the Holy Spirit. This also used in the inner wings of the angels and in the brocades on the robes of the popes. The shining gold brocades were painted by lead tin yellow pigments.
Looking more closely at the Adoration of the Mystic Lamb, we discover a number of details about the colour of the artwork. Each and every gemstone is shining like real jewels in their papal crowns. The popes are holding their majestic sticks which are also reflecting sunlight. The same thing happens with the chalice. Golden lights are emitting at the top and bottom of the chalice. Oil paint helped Jan van Eyck to maintain more or less luminance by adding more brushstrokes. Oil paint dried slowly, but it was possible to work upon the painting as many times as the artist wanted. The reflections on the chalice were possible by adding oil paint into a couple of layers. The same thing was very hard with egg tempera. Egg tempera was another method of painting used in the Renaissances times mainly in the Italian provinces. The egg yolk was blend with colour pigments but dried very quickly. Using oil paint instead of egg tempera, helped Jan van Eyck to pay close attention to detail. Every windowpane of the buildings, every leaf of the trees were rendered. Probably, for all of the descriptive effects made by oil, Jan van Eyck was sometimes called incorrectly, the inventor of oil painting.
Probably, the Northern Renaissance artists were most proficient
with blue. By the fifteenth century, blue was the most expensive colour. The pigments were called ultramarine. The best quality blue came across today’s Afghanistan. The route was from Afghanistan to Iraq then Antwerp, today's Belgium. So blue was expensive. It was so expensive that by that time artists used very little of it. On the contrary, Germany produced azurite to make red. So it was much cheaper comparatively than blue. Both ultramarine and azurite were produced and sold in different qualities. By the fifteenth century, one ounce of ultramarine was equivalent to 8 pounds of vermillion or 16 pounds of lead white. Even azurite was ten times cheaper than ultramarine. So, it’s no exception that blue is the rarest colour in the painting. In this painting, Van Eyck made his final glazes with most costly ultramarine. It was only used in the robes of the standing prophet and the male martyrs. In the Arnolfini Portrait, blue is used in the robes of the bride only.
The Ghent Altarpiece was painted on a wood panel, oil on oak, possibly Baltic oak. Baltic oak was very straight, long and superior surface compared to English Oak, Spanish poplar or pine. Baltic Oaks were collected from dense forests and the planks were tall and flat. Because of these two reasons, Baltic wood was suitable for oil painting. It was of the utmost important to find quality wood. The Flemish painters did not use green or sap wood at all. According to the Antwerp regulations, they only used oven dried wood. Both of the opened and closed panels of the Ghent Altarpieces used dried Baltic oak. It was
the maximum size planks found that time, nearly 12 feet each. After selecting the planks, painters in the lower countries also used pine resin on the surface of the wood to make the colour glazy. Oil on dry oak was sustainable and after long time it only made some craquelure. Nearly after six hundred years, the colours are bright, though a couple of theft and restorations were attempted.
The Flemish artists were the pioneers in the field of oil paint. Not only the northern painters were masters of colour and iconography, but also in the use of different mediums with oil. Jan van Eyck was the master of the masters. The detailed observation of nature and contemporary life can be seen in his painting. The Ghent Altarpiece: The Adoration of the Mystic Lamb and the Arnolfini Protrait both are unprecedented masterpiece of work of art by the combination of colour, oil and medium.
 Susan Jones, “Painting in Oil in the Low Countries and Its Spread to Southern Europe.” In Heilbrunn Timeline of Art History. New York: The Metropolitan Museum of Art, 2000–.<https://www.metmuseum.org/toah/hd/optg/hd_optg.htm>(October 2002).
 Susie Nash, Northern Renaissance Art (Oxford: Oxford University Press, 2008), 206-8.
 Nash, Northern Renaissance Art, 206-8.
 Jones, Heilbrunn Timeline of Art History, October 2002.
 Nash, Northern Renaissance Art, 199-200.