These flat representations are emphasized by the splendor of the gold leafing. Though age and the photographed version of the altarpiece has caused the glossy effect of the tempera paint to fade, the high gloss of the paint paired with the brightness of the gold leaf would have highlighted the enactments of Jesus' life immensely, as the painting was meant to do. In all, tempera was likely a favorite in 14th century religious art because of its ability to reflect and portray a spiritual message. .
According to Kleiner, oil paint has been used as far back as the 8th century. However, oil painting medium did not become popular, or well known, until the 15th century, where it was favored by many Northern European painters. The use of oil medium may have risen in popularity because of the growing use of natural Humanism in late medieval art. As Kleiner explains, the use and availability of richer dyes and the ability to use heavier layers of paint without the risk of premature cracking – like in tempera paint – gave artists the ability to create deep tones, detailed shadows, and exquisite senses of space within their artwork, without the need of expansive and glaring gold leaf. Hubert and Jan van Eyck's Ghent Altarpiece in the Saint Bavo Cathedral in Belgium, circa 1427, displays a remarkable example of oil medium in Northern European art. Not only is there an amazing sense of naturalism and light, but the deep depth of the painting creates the illusion that one is peeing through a window and into the room in which the angel and the virgin are standing. This painting also ties in secular trends, as the donors of the painting are depicted in the smaller frames on the bottom left and right of the altarpiece. Additionally, the virgin's balcony depicts a background of a 15th century Belgium cityscape, indicating the importance of Christendom in every day life in 15th century Belgium.
