Gold leaf
Van Eyck's superb oil painting technique is evident throughout. Gold leaf is only used for the seven rays coming in from the left; paint is used for all the gold on Gabriel, often worked wet-on-wet to achieve the textural effects of his brocaded clothes. In a shadowy area behind the stool van Eyck worked a glaze with his fingers. The play of light over the many different textures in the painting is brilliantly rendered, and the illusionistic detail, especially in Gabriel's rich costume, is exceptional.