Hue
Veneziano, Domenico. The Madonna and Child Enthroned with SS. Francis, John the Baptist, Zenobius and Lucy. 1445
Applying layers of different colors in oil glazing techniques result in hue variation. The original tempera painting has only a few elementary colors like red, blue, yellow, and teal. The limitation of the artists’ hue selection was caused by the canon which did not accept the practice of mixing colors. However, as the oil glazing technique was introduced, artists started to explore adding complementary colored layers. The second illustration above shows how certain colors could have been painted if they used the oil glazing technique of overlaying different colors. The most common mixture is applying green layers on red for a brown or olive green color, depending on the ratio of the complementary colors. This not only creates more variation in hue but also more naturalistic value modeling when painting shadows. Although Renaissance painters like Leonardo were aware of this layering technique, they seem to prefer maintaining uncorrupted pure pigments due to the constraints from the canon.
Saturation
Veneziano, Domenico. The Madonna and Child Enthroned with SS. Francis, John the Baptist, Zenobius and Lucy. 1445
The previous video illustrates how the oil glazing technique allows artists to express a higher level of color saturation. The original tempera painting in the beginning of the video demonstrates both methods of Cennini's up modeling technique and Alberti’s up and down modeling technique. However, these techniques hinder artists from maintaining jewel-like colors because of mixing the pure pigments with white for higher value (up modeling) and black for lower value (down modeling). Overcoming this limitation, later, the video demonstrates an application of the oil glazing technique in terms of increasing saturation level. The colors can be more saturated in all ranges of values. This occurs when the artists control the ratio of pigment to oil glaze. The more pigments they paint, the less underpainting shows through, and the darker value there can be expressed without dimming its saturation.
Value
Veneziano, Domenico. The Madonna and Child Enthroned with SS. Francis, John the Baptist, Zenobius and Lucy. 1445
Eyck, Jan Van. The Madonna with Canon van der Paele. 1436 (right).
Eyck, Jan Van. The Madonna with Canon van der Paele. 1436 (right).
Artists who apply up and down modeling techniques, either or both, for tempera paintings had to sacrifice expressing great ranges of value in order to maintain high levels of saturation. The tempera painting on the left is adjusted in value as if it were painted in oil. Unlike the original painting, contrast between light and dark (from low to high value) increases along with the saturation level. This portrays how the oil glazing technique creates transparency that reveals the value shifts in the underpainting, making smoother transitions in various value levels. Like the above Jan van Eyck painting, one can see the dramatically widened range of value. The lowest and the highest level of both paintings have approximately the same levels of value.